u-boot/fs/fat/fat.c

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/*
* fat.c
*
* R/O (V)FAT 12/16/32 filesystem implementation by Marcus Sundberg
*
* 2002-07-28 - rjones@nexus-tech.net - ported to ppcboot v1.1.6
* 2003-03-10 - kharris@nexus-tech.net - ported to uboot
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <common.h>
#include <config.h>
#include <exports.h>
#include <fat.h>
#include <asm/byteorder.h>
#include <part.h>
#include <malloc.h>
#include <linux/compiler.h>
#include <linux/ctype.h>
#ifdef CONFIG_SUPPORT_VFAT
static const int vfat_enabled = 1;
#else
static const int vfat_enabled = 0;
#endif
/*
* Convert a string to lowercase.
*/
static void downcase(char *str)
{
while (*str != '\0') {
*str = tolower(*str);
str++;
}
}
static block_dev_desc_t *cur_dev;
static disk_partition_t cur_part_info;
#define DOS_BOOT_MAGIC_OFFSET 0x1fe
#define DOS_FS_TYPE_OFFSET 0x36
#define DOS_FS32_TYPE_OFFSET 0x52
static int disk_read(__u32 block, __u32 nr_blocks, void *buf)
{
if (!cur_dev || !cur_dev->block_read)
return -1;
return cur_dev->block_read(cur_dev->dev,
cur_part_info.start + block, nr_blocks, buf);
}
int fat_set_blk_dev(block_dev_desc_t *dev_desc, disk_partition_t *info)
{
ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
cur_dev = dev_desc;
cur_part_info = *info;
/* Make sure it has a valid FAT header */
if (disk_read(0, 1, buffer) != 1) {
cur_dev = NULL;
return -1;
}
/* Check if it's actually a DOS volume */
if (memcmp(buffer + DOS_BOOT_MAGIC_OFFSET, "\x55\xAA", 2)) {
cur_dev = NULL;
return -1;
}
/* Check for FAT12/FAT16/FAT32 filesystem */
if (!memcmp(buffer + DOS_FS_TYPE_OFFSET, "FAT", 3))
return 0;
if (!memcmp(buffer + DOS_FS32_TYPE_OFFSET, "FAT32", 5))
return 0;
cur_dev = NULL;
return -1;
}
int fat_register_device(block_dev_desc_t *dev_desc, int part_no)
{
disk_partition_t info;
/* First close any currently found FAT filesystem */
cur_dev = NULL;
/* Read the partition table, if present */
if (get_partition_info(dev_desc, part_no, &info)) {
if (part_no != 0) {
printf("** Partition %d not valid on device %d **\n",
part_no, dev_desc->dev);
return -1;
}
info.start = 0;
info.size = dev_desc->lba;
info.blksz = dev_desc->blksz;
info.name[0] = 0;
info.type[0] = 0;
info.bootable = 0;
#ifdef CONFIG_PARTITION_UUIDS
info.uuid[0] = 0;
#endif
}
return fat_set_blk_dev(dev_desc, &info);
}
/*
* Get the first occurence of a directory delimiter ('/' or '\') in a string.
* Return index into string if found, -1 otherwise.
*/
static int dirdelim(char *str)
{
char *start = str;
while (*str != '\0') {
if (ISDIRDELIM(*str))
return str - start;
str++;
}
return -1;
}
/*
* Extract zero terminated short name from a directory entry.
*/
static void get_name(dir_entry *dirent, char *s_name)
{
char *ptr;
memcpy(s_name, dirent->name, 8);
s_name[8] = '\0';
ptr = s_name;
while (*ptr && *ptr != ' ')
ptr++;
if (dirent->ext[0] && dirent->ext[0] != ' ') {
*ptr = '.';
ptr++;
memcpy(ptr, dirent->ext, 3);
ptr[3] = '\0';
while (*ptr && *ptr != ' ')
ptr++;
}
*ptr = '\0';
if (*s_name == DELETED_FLAG)
*s_name = '\0';
else if (*s_name == aRING)
*s_name = DELETED_FLAG;
downcase(s_name);
}
/*
* Get the entry at index 'entry' in a FAT (12/16/32) table.
* On failure 0x00 is returned.
*/
static __u32 get_fatent(fsdata *mydata, __u32 entry)
{
__u32 bufnum;
__u32 off16, offset;
__u32 ret = 0x00;
__u16 val1, val2;
switch (mydata->fatsize) {
case 32:
bufnum = entry / FAT32BUFSIZE;
offset = entry - bufnum * FAT32BUFSIZE;
break;
case 16:
bufnum = entry / FAT16BUFSIZE;
offset = entry - bufnum * FAT16BUFSIZE;
break;
case 12:
bufnum = entry / FAT12BUFSIZE;
offset = entry - bufnum * FAT12BUFSIZE;
break;
default:
/* Unsupported FAT size */
return ret;
}
debug("FAT%d: entry: 0x%04x = %d, offset: 0x%04x = %d\n",
mydata->fatsize, entry, entry, offset, offset);
/* Read a new block of FAT entries into the cache. */
if (bufnum != mydata->fatbufnum) {
__u32 getsize = FATBUFBLOCKS;
__u8 *bufptr = mydata->fatbuf;
__u32 fatlength = mydata->fatlength;
__u32 startblock = bufnum * FATBUFBLOCKS;
if (startblock + getsize > fatlength)
getsize = fatlength - startblock;
startblock += mydata->fat_sect; /* Offset from start of disk */
if (disk_read(startblock, getsize, bufptr) < 0) {
debug("Error reading FAT blocks\n");
return ret;
}
mydata->fatbufnum = bufnum;
}
/* Get the actual entry from the table */
switch (mydata->fatsize) {
case 32:
ret = FAT2CPU32(((__u32 *) mydata->fatbuf)[offset]);
break;
case 16:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[offset]);
break;
case 12:
off16 = (offset * 3) / 4;
switch (offset & 0x3) {
case 0:
ret = FAT2CPU16(((__u16 *) mydata->fatbuf)[off16]);
ret &= 0xfff;
break;
case 1:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xf000;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x00ff;
ret = (val2 << 4) | (val1 >> 12);
break;
case 2:
val1 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
val1 &= 0xff00;
val2 = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16 + 1]);
val2 &= 0x000f;
ret = (val2 << 8) | (val1 >> 8);
break;
case 3:
ret = FAT2CPU16(((__u16 *)mydata->fatbuf)[off16]);
ret = (ret & 0xfff0) >> 4;
break;
default:
break;
}
break;
}
debug("FAT%d: ret: %08x, offset: %04x\n",
mydata->fatsize, ret, offset);
return ret;
}
/*
* Read at most 'size' bytes from the specified cluster into 'buffer'.
* Return 0 on success, -1 otherwise.
*/
static int
get_cluster(fsdata *mydata, __u32 clustnum, __u8 *buffer, unsigned long size)
{
__u32 idx = 0;
__u32 startsect;
int ret;
if (clustnum > 0) {
startsect = mydata->data_begin +
clustnum * mydata->clust_size;
} else {
startsect = mydata->rootdir_sect;
}
debug("gc - clustnum: %d, startsect: %d\n", clustnum, startsect);
if ((unsigned long)buffer & (ARCH_DMA_MINALIGN - 1)) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
printf("FAT: Misaligned buffer address (%p)\n", buffer);
while (size >= mydata->sect_size) {
ret = disk_read(startsect++, 1, tmpbuf);
if (ret != 1) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(buffer, tmpbuf, mydata->sect_size);
buffer += mydata->sect_size;
size -= mydata->sect_size;
}
} else {
idx = size / mydata->sect_size;
ret = disk_read(startsect, idx, buffer);
if (ret != idx) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
startsect += idx;
idx *= mydata->sect_size;
buffer += idx;
size -= idx;
}
if (size) {
ALLOC_CACHE_ALIGN_BUFFER(__u8, tmpbuf, mydata->sect_size);
ret = disk_read(startsect, 1, tmpbuf);
if (ret != 1) {
debug("Error reading data (got %d)\n", ret);
return -1;
}
memcpy(buffer, tmpbuf, size);
}
return 0;
}
/*
* Read at most 'maxsize' bytes from 'pos' in the file associated with 'dentptr'
* into 'buffer'.
* Update the number of bytes read in *gotsize or return -1 on fatal errors.
*/
__u8 get_contents_vfatname_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
static int get_contents(fsdata *mydata, dir_entry *dentptr, loff_t pos,
__u8 *buffer, loff_t maxsize, loff_t *gotsize)
{
loff_t filesize = FAT2CPU32(dentptr->size);
unsigned int bytesperclust = mydata->clust_size * mydata->sect_size;
__u32 curclust = START(dentptr);
__u32 endclust, newclust;
loff_t actsize;
*gotsize = 0;
debug("Filesize: %llu bytes\n", filesize);
if (pos >= filesize) {
debug("Read position past EOF: %llu\n", pos);
return 0;
}
if (maxsize > 0 && filesize > pos + maxsize)
filesize = pos + maxsize;
debug("%llu bytes\n", filesize);
actsize = bytesperclust;
/* go to cluster at pos */
while (actsize <= pos) {
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return 0;
}
actsize += bytesperclust;
}
/* actsize > pos */
actsize -= bytesperclust;
filesize -= actsize;
pos -= actsize;
/* align to beginning of next cluster if any */
if (pos) {
actsize = min(filesize, (loff_t)bytesperclust);
if (get_cluster(mydata, curclust, get_contents_vfatname_block,
(int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
filesize -= actsize;
actsize -= pos;
memcpy(buffer, get_contents_vfatname_block + pos, actsize);
*gotsize += actsize;
if (!filesize)
return 0;
buffer += actsize;
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
debug("Invalid FAT entry\n");
return 0;
}
}
actsize = bytesperclust;
endclust = curclust;
do {
/* search for consecutive clusters */
while (actsize < filesize) {
newclust = get_fatent(mydata, endclust);
if ((newclust - 1) != endclust)
goto getit;
if (CHECK_CLUST(newclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", newclust);
debug("Invalid FAT entry\n");
return 0;
}
endclust = newclust;
actsize += bytesperclust;
}
/* get remaining bytes */
actsize = filesize;
if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
*gotsize += actsize;
return 0;
getit:
if (get_cluster(mydata, curclust, buffer, (int)actsize) != 0) {
printf("Error reading cluster\n");
return -1;
}
*gotsize += (int)actsize;
filesize -= actsize;
buffer += actsize;
curclust = get_fatent(mydata, endclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return 0;
}
actsize = bytesperclust;
endclust = curclust;
} while (1);
}
/*
* Extract the file name information from 'slotptr' into 'l_name',
* starting at l_name[*idx].
* Return 1 if terminator (zero byte) is found, 0 otherwise.
*/
static int slot2str(dir_slot *slotptr, char *l_name, int *idx)
{
int j;
for (j = 0; j <= 8; j += 2) {
l_name[*idx] = slotptr->name0_4[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
for (j = 0; j <= 10; j += 2) {
l_name[*idx] = slotptr->name5_10[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
for (j = 0; j <= 2; j += 2) {
l_name[*idx] = slotptr->name11_12[j];
if (l_name[*idx] == 0x00)
return 1;
(*idx)++;
}
return 0;
}
/*
* Extract the full long filename starting at 'retdent' (which is really
* a slot) into 'l_name'. If successful also copy the real directory entry
* into 'retdent'
* Return 0 on success, -1 otherwise.
*/
static int
get_vfatname(fsdata *mydata, int curclust, __u8 *cluster,
dir_entry *retdent, char *l_name)
{
dir_entry *realdent;
dir_slot *slotptr = (dir_slot *)retdent;
__u8 *buflimit = cluster + mydata->sect_size * ((curclust == 0) ?
PREFETCH_BLOCKS :
mydata->clust_size);
__u8 counter = (slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff;
int idx = 0;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
if (counter > VFAT_MAXSEQ) {
debug("Error: VFAT name is too long\n");
return -1;
}
while ((__u8 *)slotptr < buflimit) {
if (counter == 0)
break;
if (((slotptr->id & ~LAST_LONG_ENTRY_MASK) & 0xff) != counter)
return -1;
slotptr++;
counter--;
}
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
if ((__u8 *)slotptr >= buflimit) {
dir_slot *slotptr2;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
if (curclust == 0)
return -1;
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return -1;
}
if (get_cluster(mydata, curclust, get_contents_vfatname_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return -1;
}
slotptr2 = (dir_slot *)get_contents_vfatname_block;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
while (counter > 0) {
if (((slotptr2->id & ~LAST_LONG_ENTRY_MASK)
& 0xff) != counter)
return -1;
slotptr2++;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
counter--;
}
/* Save the real directory entry */
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
realdent = (dir_entry *)slotptr2;
while ((__u8 *)slotptr2 > get_contents_vfatname_block) {
slotptr2--;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
slot2str(slotptr2, l_name, &idx);
}
} else {
/* Save the real directory entry */
realdent = (dir_entry *)slotptr;
}
do {
slotptr--;
if (slot2str(slotptr, l_name, &idx))
break;
} while (!(slotptr->id & LAST_LONG_ENTRY_MASK));
l_name[idx] = '\0';
if (*l_name == DELETED_FLAG)
*l_name = '\0';
else if (*l_name == aRING)
*l_name = DELETED_FLAG;
downcase(l_name);
/* Return the real directory entry */
memcpy(retdent, realdent, sizeof(dir_entry));
return 0;
}
/* Calculate short name checksum */
static __u8 mkcksum(const char name[8], const char ext[3])
{
int i;
__u8 ret = 0;
for (i = 0; i < 8; i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + name[i];
for (i = 0; i < 3; i++)
ret = (((ret & 1) << 7) | ((ret & 0xfe) >> 1)) + ext[i];
return ret;
}
/*
* Get the directory entry associated with 'filename' from the directory
* starting at 'startsect'
*/
__u8 get_dentfromdir_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
static dir_entry *get_dentfromdir(fsdata *mydata, int startsect,
char *filename, dir_entry *retdent,
int dols)
{
__u16 prevcksum = 0xffff;
__u32 curclust = START(retdent);
int files = 0, dirs = 0;
debug("get_dentfromdir: %s\n", filename);
while (1) {
dir_entry *dentptr;
int i;
if (get_cluster(mydata, curclust, get_dentfromdir_block,
mydata->clust_size * mydata->sect_size) != 0) {
debug("Error: reading directory block\n");
return NULL;
}
dentptr = (dir_entry *)get_dentfromdir_block;
for (i = 0; i < DIRENTSPERCLUST; i++) {
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
l_name[0] = '\0';
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if ((dentptr->attr & ATTR_VOLUME)) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum = ((dir_slot *)dentptr)->alias_checksum;
get_vfatname(mydata, curclust,
get_dentfromdir_block,
dentptr, l_name);
if (dols) {
int isdir;
char dirc;
int doit = 0;
isdir = (dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("vfatname: |%s|\n", l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
}
if (dentptr->name[0] == 0) {
if (dols) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
}
debug("Dentname == NULL - %d\n", i);
return NULL;
}
if (vfat_enabled) {
__u8 csum = mkcksum(dentptr->name, dentptr->ext);
if (dols && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
}
get_name(dentptr, s_name);
if (dols) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(filename, s_name)
&& strcmp(filename, l_name)) {
debug("Mismatch: |%s|%s|\n", s_name, l_name);
dentptr++;
continue;
}
memcpy(retdent, dentptr, sizeof(dir_entry));
debug("DentName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
(dentptr->attr & ATTR_DIR) ? "(DIR)" : "");
return retdent;
}
curclust = get_fatent(mydata, curclust);
if (CHECK_CLUST(curclust, mydata->fatsize)) {
debug("curclust: 0x%x\n", curclust);
printf("Invalid FAT entry\n");
return NULL;
}
}
return NULL;
}
/*
* Read boot sector and volume info from a FAT filesystem
*/
static int
read_bootsectandvi(boot_sector *bs, volume_info *volinfo, int *fatsize)
{
__u8 *block;
volume_info *vistart;
int ret = 0;
if (cur_dev == NULL) {
debug("Error: no device selected\n");
return -1;
}
block = memalign(ARCH_DMA_MINALIGN, cur_dev->blksz);
if (block == NULL) {
debug("Error: allocating block\n");
return -1;
}
if (disk_read(0, 1, block) < 0) {
debug("Error: reading block\n");
goto fail;
}
memcpy(bs, block, sizeof(boot_sector));
bs->reserved = FAT2CPU16(bs->reserved);
bs->fat_length = FAT2CPU16(bs->fat_length);
bs->secs_track = FAT2CPU16(bs->secs_track);
bs->heads = FAT2CPU16(bs->heads);
bs->total_sect = FAT2CPU32(bs->total_sect);
/* FAT32 entries */
if (bs->fat_length == 0) {
/* Assume FAT32 */
bs->fat32_length = FAT2CPU32(bs->fat32_length);
bs->flags = FAT2CPU16(bs->flags);
bs->root_cluster = FAT2CPU32(bs->root_cluster);
bs->info_sector = FAT2CPU16(bs->info_sector);
bs->backup_boot = FAT2CPU16(bs->backup_boot);
vistart = (volume_info *)(block + sizeof(boot_sector));
*fatsize = 32;
} else {
vistart = (volume_info *)&(bs->fat32_length);
*fatsize = 0;
}
memcpy(volinfo, vistart, sizeof(volume_info));
if (*fatsize == 32) {
if (strncmp(FAT32_SIGN, vistart->fs_type, SIGNLEN) == 0)
goto exit;
} else {
if (strncmp(FAT12_SIGN, vistart->fs_type, SIGNLEN) == 0) {
*fatsize = 12;
goto exit;
}
if (strncmp(FAT16_SIGN, vistart->fs_type, SIGNLEN) == 0) {
*fatsize = 16;
goto exit;
}
}
debug("Error: broken fs_type sign\n");
fail:
ret = -1;
exit:
free(block);
return ret;
}
__u8 do_fat_read_at_block[MAX_CLUSTSIZE]
__aligned(ARCH_DMA_MINALIGN);
int do_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, int dols, int dogetsize, loff_t *size)
{
char fnamecopy[2048];
boot_sector bs;
volume_info volinfo;
fsdata datablock;
fsdata *mydata = &datablock;
dir_entry *dentptr = NULL;
__u16 prevcksum = 0xffff;
char *subname = "";
__u32 cursect;
int idx, isdir = 0;
int files = 0, dirs = 0;
int ret = -1;
int firsttime;
__u32 root_cluster = 0;
__u32 read_blk;
int rootdir_size = 0;
int buffer_blk_cnt;
int do_read;
__u8 *dir_ptr;
if (read_bootsectandvi(&bs, &volinfo, &mydata->fatsize)) {
debug("Error: reading boot sector\n");
return -1;
}
if (mydata->fatsize == 32) {
root_cluster = bs.root_cluster;
mydata->fatlength = bs.fat32_length;
} else {
mydata->fatlength = bs.fat_length;
}
mydata->fat_sect = bs.reserved;
cursect = mydata->rootdir_sect
= mydata->fat_sect + mydata->fatlength * bs.fats;
mydata->sect_size = (bs.sector_size[1] << 8) + bs.sector_size[0];
mydata->clust_size = bs.cluster_size;
if (mydata->sect_size != cur_part_info.blksz) {
printf("Error: FAT sector size mismatch (fs=%hu, dev=%lu)\n",
mydata->sect_size, cur_part_info.blksz);
return -1;
}
if (mydata->fatsize == 32) {
mydata->data_begin = mydata->rootdir_sect -
(mydata->clust_size * 2);
} else {
rootdir_size = ((bs.dir_entries[1] * (int)256 +
bs.dir_entries[0]) *
sizeof(dir_entry)) /
mydata->sect_size;
mydata->data_begin = mydata->rootdir_sect +
rootdir_size -
(mydata->clust_size * 2);
}
mydata->fatbufnum = -1;
mydata->fatbuf = memalign(ARCH_DMA_MINALIGN, FATBUFSIZE);
if (mydata->fatbuf == NULL) {
debug("Error: allocating memory\n");
return -1;
}
if (vfat_enabled)
debug("VFAT Support enabled\n");
debug("FAT%d, fat_sect: %d, fatlength: %d\n",
mydata->fatsize, mydata->fat_sect, mydata->fatlength);
debug("Rootdir begins at cluster: %d, sector: %d, offset: %x\n"
"Data begins at: %d\n",
root_cluster,
mydata->rootdir_sect,
mydata->rootdir_sect * mydata->sect_size, mydata->data_begin);
debug("Sector size: %d, cluster size: %d\n", mydata->sect_size,
mydata->clust_size);
/* "cwd" is always the root... */
while (ISDIRDELIM(*filename))
filename++;
/* Make a copy of the filename and convert it to lowercase */
strcpy(fnamecopy, filename);
downcase(fnamecopy);
if (*fnamecopy == '\0') {
if (!dols)
goto exit;
dols = LS_ROOT;
} else if ((idx = dirdelim(fnamecopy)) >= 0) {
isdir = 1;
fnamecopy[idx] = '\0';
subname = fnamecopy + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*subname))
subname++;
} else if (dols) {
isdir = 1;
}
buffer_blk_cnt = 0;
firsttime = 1;
while (1) {
int i;
if (mydata->fatsize == 32 || firsttime) {
dir_ptr = do_fat_read_at_block;
firsttime = 0;
} else {
/**
* FAT16 sector buffer modification:
* Each loop, the second buffered block is moved to
* the buffer begin, and two next sectors are read
* next to the previously moved one. So the sector
* buffer keeps always 3 sectors for fat16.
* And the current sector is the buffer second sector
* beside the "firsttime" read, when it is the first one.
*
* PREFETCH_BLOCKS is 2 for FAT16 == loop[0:1]
* n = computed root dir sector
* loop | cursect-1 | cursect | cursect+1 |
* 0 | sector n+0 | sector n+1 | none |
* 1 | none | sector n+0 | sector n+1 |
* 0 | sector n+1 | sector n+2 | sector n+3 |
* 1 | sector n+3 | ...
*/
dir_ptr = (do_fat_read_at_block + mydata->sect_size);
memcpy(do_fat_read_at_block, dir_ptr, mydata->sect_size);
}
do_read = 1;
if (mydata->fatsize == 32 && buffer_blk_cnt)
do_read = 0;
if (do_read) {
read_blk = (mydata->fatsize == 32) ?
mydata->clust_size : PREFETCH_BLOCKS;
debug("FAT read(sect=%d, cnt:%d), clust_size=%d, DIRENTSPERBLOCK=%zd\n",
cursect, read_blk, mydata->clust_size, DIRENTSPERBLOCK);
if (disk_read(cursect, read_blk, dir_ptr) < 0) {
debug("Error: reading rootdir block\n");
goto exit;
}
dentptr = (dir_entry *)dir_ptr;
}
for (i = 0; i < DIRENTSPERBLOCK; i++) {
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
char s_name[14], l_name[VFAT_MAXLEN_BYTES];
__u8 csum;
l_name[0] = '\0';
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
if (dentptr->name[0] == DELETED_FLAG) {
dentptr++;
continue;
}
if (vfat_enabled)
csum = mkcksum(dentptr->name, dentptr->ext);
if (dentptr->attr & ATTR_VOLUME) {
if (vfat_enabled &&
(dentptr->attr & ATTR_VFAT) == ATTR_VFAT &&
(dentptr->name[0] & LAST_LONG_ENTRY_MASK)) {
prevcksum =
((dir_slot *)dentptr)->alias_checksum;
VFAT: fix processing of scattered long file name entries The U-Boot code has the following bugs related to the processing of Long File Name (LFN) entries scattered across several clusters/sectors : 1) get_vfatname() function is designed to gather scattered LFN entries by cluster chain processing - that doesn't work for FAT12/16 root directory. In other words, the function expects the following input data: 1.1) FAT32 directory (which is cluster chain based); OR 1.2) FAT12/16 non-root directory (which is also cluster chain based); OR 1.3) FAT12/16 root directory (allocated as contiguous sectors area), but all necessary information MUST be within the input buffer of filesystem cluster size (thus cluster-chain jump is never initiated). In order to accomplish the last condition, root directory parsing code in do_fat_read() uses the following trick: read-out cluster-size block, process only first sector (512 bytes), then shift 512 forward, read-out cluster-size block and so on. This works great unless cluster size is equal to 512 bytes (in a case you have a small partition), or long file name entries are scattered across three sectors, see 4) for details. 2) Despite of the fact that get_vfatname() supports FAT32 root directory browsing, do_fat_read() function doesn't send current cluster number correctly, so root directory look-up doesn't work correctly. 3) get_vfatname() doesn't gather scattered entries correctly also is the case when all LFN entries are located at the end of the source cluster, but real directory entry (which must be returned) is at the only beginning of the next one. No error detected, the resulting directory entry returned contains a semi-random information (wrong size, wrong start cluster number and so on) i.e. the entry is not accessible. 4) LFN (VFAT) allows up to 20 entries (slots) each containing 26 bytes (13 UTF-16 code units) to represent a single long file name i.e. up to 520 bytes. U-Boot allocates 256 bytes buffer instead, i.e. 10 or more LFN slots record may cause buffer overflow / memory corruption. Also, it's worth to mention that 20+1 slots occupy 672 bytes space which may take more than one cluster of 512 bytes (medium-size FAT32 or small FAT16 partition) - get_vfatname() function doesn't support such case as well. The patch attached fixes these problems in the following way: - keep using 256 bytes buffer for a long file name, but safely prevent a possible buffer overflow (skip LFN processing, if it contains 10 or more slots). - explicitly specify FAT12/16 root directory parsing buffer size, instead of relying on cluster size. The value used is a double sector size (to store current sector and the next one). This fixes the first problem and increases performance on big FAT12/16 partitions; - send current cluster number (FAT32) to get_vfatname() during root directory processing; - use LFN counter to seek the real directory entry in get_vfatname() - fixes the third problem; - skip deleted entries in the root directory (to prevent bogus buffer overflow detection and LFN counter steps). Note: it's not advised to split up the patch, because a separate part may operate incorrectly. Signed-off-by: Mikhail Zolotaryov <lebon@lebon.org.ua>
2010-09-08 14:06:03 +00:00
get_vfatname(mydata,
root_cluster,
dir_ptr,
dentptr, l_name);
if (dols == LS_ROOT) {
char dirc;
int doit = 0;
int isdir =
(dentptr->attr & ATTR_DIR);
if (isdir) {
dirs++;
dirc = '/';
doit = 1;
} else {
dirc = ' ';
if (l_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
l_name,
dirc);
} else {
printf(" %s%c\n",
l_name,
dirc);
}
}
dentptr++;
continue;
}
debug("Rootvfatname: |%s|\n",
l_name);
} else {
/* Volume label or VFAT entry */
dentptr++;
continue;
}
} else if (dentptr->name[0] == 0) {
debug("RootDentname == NULL - %d\n", i);
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
ret = 0;
}
goto exit;
}
else if (vfat_enabled &&
dols == LS_ROOT && csum == prevcksum) {
prevcksum = 0xffff;
dentptr++;
continue;
}
get_name(dentptr, s_name);
if (dols == LS_ROOT) {
int isdir = (dentptr->attr & ATTR_DIR);
char dirc;
int doit = 0;
if (isdir) {
dirc = '/';
if (s_name[0] != 0) {
dirs++;
doit = 1;
}
} else {
dirc = ' ';
if (s_name[0] != 0) {
files++;
doit = 1;
}
}
if (doit) {
if (dirc == ' ') {
printf(" %8u %s%c\n",
FAT2CPU32(dentptr->size),
s_name, dirc);
} else {
printf(" %s%c\n",
s_name, dirc);
}
}
dentptr++;
continue;
}
if (strcmp(fnamecopy, s_name)
&& strcmp(fnamecopy, l_name)) {
debug("RootMismatch: |%s|%s|\n", s_name,
l_name);
dentptr++;
continue;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
debug("RootName: %s", s_name);
debug(", start: 0x%x", START(dentptr));
debug(", size: 0x%x %s\n",
FAT2CPU32(dentptr->size),
isdir ? "(DIR)" : "");
goto rootdir_done; /* We got a match */
}
debug("END LOOP: buffer_blk_cnt=%d clust_size=%d\n", buffer_blk_cnt,
mydata->clust_size);
/*
* On FAT32 we must fetch the FAT entries for the next
* root directory clusters when a cluster has been
* completely processed.
*/
++buffer_blk_cnt;
int rootdir_end = 0;
if (mydata->fatsize == 32) {
if (buffer_blk_cnt == mydata->clust_size) {
int nxtsect = 0;
int nxt_clust = 0;
nxt_clust = get_fatent(mydata, root_cluster);
rootdir_end = CHECK_CLUST(nxt_clust, 32);
nxtsect = mydata->data_begin +
(nxt_clust * mydata->clust_size);
root_cluster = nxt_clust;
cursect = nxtsect;
buffer_blk_cnt = 0;
}
} else {
if (buffer_blk_cnt == PREFETCH_BLOCKS)
buffer_blk_cnt = 0;
rootdir_end = (++cursect - mydata->rootdir_sect >=
rootdir_size);
}
/* If end of rootdir reached */
if (rootdir_end) {
if (dols == LS_ROOT) {
printf("\n%d file(s), %d dir(s)\n\n",
files, dirs);
*size = 0;
}
goto exit;
}
}
rootdir_done:
firsttime = 1;
while (isdir) {
int startsect = mydata->data_begin
+ START(dentptr) * mydata->clust_size;
dir_entry dent;
char *nextname = NULL;
dent = *dentptr;
dentptr = &dent;
idx = dirdelim(subname);
if (idx >= 0) {
subname[idx] = '\0';
nextname = subname + idx + 1;
/* Handle multiple delimiters */
while (ISDIRDELIM(*nextname))
nextname++;
if (dols && *nextname == '\0')
firsttime = 0;
} else {
if (dols && firsttime) {
firsttime = 0;
} else {
isdir = 0;
}
}
if (get_dentfromdir(mydata, startsect, subname, dentptr,
isdir ? 0 : dols) == NULL) {
if (dols && !isdir)
*size = 0;
goto exit;
}
if (isdir && !(dentptr->attr & ATTR_DIR))
goto exit;
if (idx >= 0)
subname = nextname;
}
if (dogetsize) {
*size = FAT2CPU32(dentptr->size);
ret = 0;
} else {
ret = get_contents(mydata, dentptr, pos, buffer, maxsize, size);
}
debug("Size: %u, got: %llu\n", FAT2CPU32(dentptr->size), *size);
exit:
free(mydata->fatbuf);
return ret;
}
int do_fat_read(const char *filename, void *buffer, loff_t maxsize, int dols,
loff_t *actread)
{
return do_fat_read_at(filename, 0, buffer, maxsize, dols, 0, actread);
}
int file_fat_detectfs(void)
{
boot_sector bs;
volume_info volinfo;
int fatsize;
char vol_label[12];
if (cur_dev == NULL) {
printf("No current device\n");
return 1;
}
#if defined(CONFIG_CMD_IDE) || \
defined(CONFIG_CMD_SATA) || \
defined(CONFIG_CMD_SCSI) || \
defined(CONFIG_CMD_USB) || \
defined(CONFIG_MMC)
printf("Interface: ");
switch (cur_dev->if_type) {
case IF_TYPE_IDE:
printf("IDE");
break;
case IF_TYPE_SATA:
printf("SATA");
break;
case IF_TYPE_SCSI:
printf("SCSI");
break;
case IF_TYPE_ATAPI:
printf("ATAPI");
break;
case IF_TYPE_USB:
printf("USB");
break;
case IF_TYPE_DOC:
printf("DOC");
break;
case IF_TYPE_MMC:
printf("MMC");
break;
default:
printf("Unknown");
}
printf("\n Device %d: ", cur_dev->dev);
dev_print(cur_dev);
#endif
if (read_bootsectandvi(&bs, &volinfo, &fatsize)) {
printf("\nNo valid FAT fs found\n");
return 1;
}
memcpy(vol_label, volinfo.volume_label, 11);
vol_label[11] = '\0';
volinfo.fs_type[5] = '\0';
printf("Filesystem: %s \"%s\"\n", volinfo.fs_type, vol_label);
return 0;
}
int file_fat_ls(const char *dir)
{
loff_t size;
return do_fat_read(dir, NULL, 0, LS_YES, &size);
}
int fat_exists(const char *filename)
{
int ret;
loff_t size;
ret = do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, &size);
return ret == 0;
}
int fat_size(const char *filename, loff_t *size)
{
return do_fat_read_at(filename, 0, NULL, 0, LS_NO, 1, size);
}
int file_fat_read_at(const char *filename, loff_t pos, void *buffer,
loff_t maxsize, loff_t *actread)
{
printf("reading %s\n", filename);
return do_fat_read_at(filename, pos, buffer, maxsize, LS_NO, 0,
actread);
}
int file_fat_read(const char *filename, void *buffer, int maxsize)
{
loff_t actread;
int ret;
ret = file_fat_read_at(filename, 0, buffer, maxsize, &actread);
if (ret)
return ret;
else
return actread;
}
int fat_read_file(const char *filename, void *buf, loff_t offset, loff_t len,
loff_t *actread)
{
int ret;
ret = file_fat_read_at(filename, offset, buf, len, actread);
if (ret)
printf("** Unable to read file %s **\n", filename);
return ret;
}
void fat_close(void)
{
}