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open5gs/lib/asn1c/common/per_support.c

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/*
* Copyright (c) 2005-2017 Lev Walkin <vlm@lionet.info>. All rights reserved.
* Redistribution and modifications are permitted subject to BSD license.
*/
#include <asn_system.h>
#include <asn_internal.h>
#include <per_support.h>
/*
* X.691-201508 #10.9 General rules for encoding a length determinant.
* Get the optionally constrained length "n" from the stream.
*/
ssize_t
uper_get_length(asn_per_data_t *pd, int ebits, size_t lower_bound,
int *repeat) {
ssize_t value;
*repeat = 0;
/* #11.9.4.1 Encoding if constrained (according to effective bits) */
if(ebits >= 0 && ebits <= 16) {
value = per_get_few_bits(pd, ebits);
if(value >= 0) value += lower_bound;
return value;
}
value = per_get_few_bits(pd, 8);
if((value & 0x80) == 0) { /* #11.9.3.6 */
return (value & 0x7F);
} else if((value & 0x40) == 0) { /* #11.9.3.7 */
/* bit 8 ... set to 1 and bit 7 ... set to zero */
value = ((value & 0x3f) << 8) | per_get_few_bits(pd, 8);
return value; /* potential -1 from per_get_few_bits passes through. */
} else if(value < 0) {
ASN_DEBUG("END of stream reached for PER");
return -1;
}
value &= 0x3f; /* this is "m" from X.691, #11.9.3.8 */
if(value < 1 || value > 4) {
return -1; /* Prohibited by #11.9.3.8 */
}
*repeat = 1;
return (16384 * value);
}
/*
* Get the normally small length "n".
* This procedure used to decode length of extensions bit-maps
* for SET and SEQUENCE types.
*/
ssize_t
uper_get_nslength(asn_per_data_t *pd) {
ssize_t length;
ASN_DEBUG("Getting normally small length");
if(per_get_few_bits(pd, 1) == 0) {
length = per_get_few_bits(pd, 6) + 1;
if(length <= 0) return -1;
ASN_DEBUG("l=%d", (int)length);
return length;
} else {
int repeat;
length = uper_get_length(pd, -1, 0, &repeat);
if(length >= 0 && !repeat) return length;
return -1; /* Error, or do not support >16K extensions */
}
}
/*
* Get the normally small non-negative whole number.
* X.691, #10.6
*/
ssize_t
uper_get_nsnnwn(asn_per_data_t *pd) {
ssize_t value;
value = per_get_few_bits(pd, 7);
if(value & 64) { /* implicit (value < 0) */
value &= 63;
value <<= 2;
value |= per_get_few_bits(pd, 2);
if(value & 128) /* implicit (value < 0) */
return -1;
if(value == 0)
return 0;
if(value >= 3)
return -1;
value = per_get_few_bits(pd, 8 * value);
return value;
}
return value;
}
/*
* X.691-11/2008, #11.6
* Encoding of a normally small non-negative whole number
*/
int
uper_put_nsnnwn(asn_per_outp_t *po, int n) {
int bytes;
if(n <= 63) {
if(n < 0) return -1;
return per_put_few_bits(po, n, 7);
}
if(n < 256)
bytes = 1;
else if(n < 65536)
bytes = 2;
else if(n < 256 * 65536)
bytes = 3;
else
return -1; /* This is not a "normally small" value */
if(per_put_few_bits(po, bytes, 8))
return -1;
return per_put_few_bits(po, n, 8 * bytes);
}
/* X.691-2008/11, #11.5.6 -> #11.3 */
int uper_get_constrained_whole_number(asn_per_data_t *pd, uintmax_t *out_value, int nbits) {
uintmax_t lhalf; /* Lower half of the number*/
intmax_t half;
if(nbits <= 31) {
half = per_get_few_bits(pd, nbits);
if(half < 0) return -1;
*out_value = half;
return 0;
}
if((size_t)nbits > 8 * sizeof(*out_value))
return -1; /* RANGE */
half = per_get_few_bits(pd, 31);
if(half < 0) return -1;
if(uper_get_constrained_whole_number(pd, &lhalf, nbits - 31))
return -1;
*out_value = ((uintmax_t)half << (nbits - 31)) | lhalf;
return 0;
}
/* X.691-2008/11, #11.5.6 -> #11.3 */
int
uper_put_constrained_whole_number_u(asn_per_outp_t *po, unsigned long v,
int nbits) {
if(nbits <= 31) {
return per_put_few_bits(po, v, nbits);
} else {
/* Put higher portion first, followed by lower 31-bit */
if(uper_put_constrained_whole_number_u(po, v >> 31, nbits - 31))
return -1;
return per_put_few_bits(po, v, 31);
}
}
/*
* X.691 (08/2015) #11.9 "General rules for encoding a length determinant"
* Put the length "n" (or part of it) into the stream.
*/
ssize_t
uper_put_length(asn_per_outp_t *po, size_t length, int *need_eom) {
int dummy = 0;
if(!need_eom) need_eom = &dummy;
if(length <= 127) { /* #11.9.3.6 */
*need_eom = 0;
return per_put_few_bits(po, length, 8)
? -1 : (ssize_t)length;
} else if(length < 16384) { /* #10.9.3.7 */
*need_eom = 0;
return per_put_few_bits(po, length|0x8000, 16)
? -1 : (ssize_t)length;
}
*need_eom = 0 == (length & 16383);
length >>= 14;
if(length > 4) {
*need_eom = 0;
length = 4;
}
return per_put_few_bits(po, 0xC0 | length, 8)
? -1 : (ssize_t)(length << 14);
}
/*
* Put the normally small length "n" into the stream.
* This procedure used to encode length of extensions bit-maps
* for SET and SEQUENCE types.
*/
int
uper_put_nslength(asn_per_outp_t *po, size_t length) {
if(length <= 64) {
/* #11.9.3.4 */
if(length == 0) return -1;
return per_put_few_bits(po, length - 1, 7) ? -1 : 0;
} else {
int need_eom = 0;
if(uper_put_length(po, length, &need_eom) != (ssize_t)length
|| need_eom) {
/* This might happen in case of >16K extensions */
return -1;
}
}
return 0;
}
static int
per__imax_range(intmax_t lb, intmax_t ub, uintmax_t *range_r) {
uintmax_t bounds_range;
if((ub < 0) == (lb < 0)) {
bounds_range = ub - lb;
} else if(lb < 0) {
assert(ub >= 0);
bounds_range = 1 + ((uintmax_t)ub + (uintmax_t)-(lb + 1));
} else {
assert(!"Unreachable");
return -1;
}
*range_r = bounds_range;
return 0;
}
int
per_imax_range_rebase(intmax_t v, intmax_t lb, intmax_t ub, uintmax_t *output) {
uintmax_t range;
assert(lb <= ub);
if(v < lb || v > ub || per__imax_range(lb, ub, &range) < 0) {
/* Range error. */
return -1;
}
/*
* Fundamentally what we're doing is returning (v-lb).
* However, this triggers undefined behavior when the word width
* of signed (v) is the same as the size of unsigned (*output).
* In practice, it triggers the UndefinedSanitizer. Therefore we shall
* compute the ranges accurately to avoid C's undefined behavior.
*/
if((v < 0) == (lb < 0)) {
*output = v-lb;
return 0;
} else if(v < 0) {
uintmax_t rebased = 1 + (uintmax_t)-(v+1) + (uintmax_t)lb;
assert(rebased <= range); /* By construction */
*output = rebased;
return 0;
} else if(lb < 0) {
uintmax_t rebased = 1 + (uintmax_t)-(lb+1) + (uintmax_t)v;
assert(rebased <= range); /* By construction */
*output = rebased;
return 0;
} else {
assert(!"Unreachable");
return -1;
}
}
int
per_long_range_rebase(long v, intmax_t lb, intmax_t ub, unsigned long *output) {
uintmax_t tmp = *output;
int rc = per_imax_range_rebase((intmax_t)v, lb, ub, &tmp);
*output = tmp;
return rc;
}
int
per_imax_range_unrebase(uintmax_t inp, intmax_t lb, intmax_t ub, intmax_t *outp) {
uintmax_t range;
if(per__imax_range(lb, ub, &range) != 0) {
return -1;
}
if(inp > range) {
/*
* We can encode something in the given number of bits that technically
* exceeds the range. This is an avenue for security errors,
* so we don't allow that.
*/
return -1;
}
if(inp <= INTMAX_MAX) {
*outp = (long)inp + lb;
} else {
*outp = (lb + INTMAX_MAX + 1) + (intmax_t)((inp - INTMAX_MAX) - 1);
}
return 0;
}
int
per_long_range_unrebase(unsigned long inp, intmax_t lb, intmax_t ub, long *outp) {
intmax_t tmp = *outp;
int rc = per_imax_range_unrebase((uintmax_t)inp, lb, ub, &tmp);
*outp = tmp;
return rc;
}
int32_t
aper_get_align(asn_per_data_t *pd) {
if(pd->nboff & 0x7) {
ASN_DEBUG("Aligning %ld bits", 8 - ((unsigned long)pd->nboff & 0x7));
return per_get_few_bits(pd, 8 - (pd->nboff & 0x7));
}
return 0;
}
ssize_t
aper_get_length(asn_per_data_t *pd, int range, int ebits, int *repeat) {
ssize_t value;
*repeat = 0;
if (range <= 65536 && range >= 0)
return aper_get_nsnnwn(pd, range);
if (aper_get_align(pd) < 0)
return -1;
if(ebits >= 0) return per_get_few_bits(pd, ebits);
value = per_get_few_bits(pd, 8);
if(value < 0) return -1;
if((value & 128) == 0) /* #10.9.3.6 */
return (value & 0x7F);
if((value & 64) == 0) { /* #10.9.3.7 */
value = ((value & 63) << 8) | per_get_few_bits(pd, 8);
if(value < 0) return -1;
return value;
}
value &= 63; /* this is "m" from X.691, #10.9.3.8 */
if(value < 1 || value > 4)
return -1;
*repeat = 1;
return (16384 * value);
}
ssize_t
aper_get_nslength(asn_per_data_t *pd) {
ssize_t length;
ASN_DEBUG("Getting normally small length");
if(per_get_few_bits(pd, 1) == 0) {
length = per_get_few_bits(pd, 6) + 1;
if(length <= 0) return -1;
ASN_DEBUG("l=%ld", length);
return length;
} else {
int repeat;
length = aper_get_length(pd, -1, -1, &repeat);
if(length >= 0 && !repeat) return length;
return -1; /* Error, or do not support >16K extensions */
}
}
#if !defined(USE_OLDER_APER_NSNNWN)
ssize_t
aper_get_nsnnwn(asn_per_data_t *pd, int range) {
ssize_t value;
int bytes = 0;
ASN_DEBUG("getting nsnnwn with range %d", range);
if(range <= 255) {
int i;
if (range < 0) return -1;
/* 1 -> 8 bits */
for (i = 1; i <= 8; i++) {
int upper = 1 << i;
if (upper >= range)
break;
}
value = per_get_few_bits(pd, i);
return value;
} else if (range == 256){
/* 1 byte */
bytes = 1;
} else if (range <= 65536) {
/* 2 bytes */
bytes = 2;
} else {
//return -1;
int length;
/* handle indefinite range */
length = per_get_few_bits(pd, 1);
if (length == 0)
return per_get_few_bits(pd, 6);
if (aper_get_align(pd) < 0)
return -1;
length = per_get_few_bits(pd, 8);
/* the length is not likely to be that big */
if (length > 4)
return -1;
value = 0;
if (per_get_many_bits(pd, (uint8_t *)&value, 0, length * 8) < 0)
return -1;
return value;
}
if (aper_get_align(pd) < 0)
return -1;
value = per_get_few_bits(pd, 8 * bytes);
return value;
}
#else /* old APER codec */
ssize_t
aper_get_nsnnwn(asn_per_data_t *pd, int dummy_range) {
ssize_t value;
ASN_DEBUG("Get the normally small non-negative whole number APER");
value = per_get_few_bits(pd, 7);
if(value & 64) { /* implicit (value < 0) */
value &= 63;
value <<= 2;
value |= per_get_few_bits(pd, 2);
if(value & 128) /* implicit (value < 0) */
return -1;
if(value == 0)
return 0;
if(value >= 3)
return -1;
value = per_get_few_bits(pd, 8 * value);
return value;
}
return value;
}
#endif /* don't use old APER */
int aper_put_align(asn_per_outp_t *po) {
if(po->nboff & 0x7) {
ASN_DEBUG("Aligning %ld bits", 8 - ((unsigned long)po->nboff & 0x7));
if(per_put_few_bits(po, 0x00, (8 - (po->nboff & 0x7))))
return -1;
}
return 0;
}
ssize_t
aper_put_length(asn_per_outp_t *po, int range, size_t length, int *need_eom) {
int dummy = 0;
if(!need_eom) need_eom = &dummy;
*need_eom = 0;
ASN_DEBUG("APER put length %zu with range %d", length, range);
/* 10.9 X.691 Note 2 */
if (range <= 65536 && range >= 0)
return aper_put_nsnnwn(po, range, length);
if (aper_put_align(po) < 0)
return -1;
if(length <= 127) /* #10.9.3.6 */{
return per_put_few_bits(po, length, 8)
? -1 : (ssize_t)length;
}
else if(length < 16384) /* #10.9.3.7 */
return per_put_few_bits(po, length|0x8000, 16)
? -1 : (ssize_t)length;
*need_eom = 0 == (length & 16383);
length >>= 14;
if(length > 4) {
*need_eom = 0;
length = 4;
}
return per_put_few_bits(po, 0xC0 | length, 8)
? -1 : (ssize_t)(length << 14);
}
int
aper_put_nslength(asn_per_outp_t *po, size_t length) {
if(length <= 64) {
/* #10.9.3.4 */
if(length == 0) return -1;
return per_put_few_bits(po, length-1, 7) ? -1 : 0;
} else {
if(aper_put_length(po, -1, length, 0) != (ssize_t)length) {
/* This might happen in case of >16K extensions */
return -1;
}
}
return 0;
}
#if !defined(USE_OLDER_APER_NSNNWN)
int
aper_put_nsnnwn(asn_per_outp_t *po, int range, int number) {
int bytes;
ASN_DEBUG("aper put nsnnwn %d with range %d", number, range);
/* 10.5.7.1 X.691 */
if(range < 0) {
int i;
for (i = 1; ; i++) {
int bits = 1 << (8 * i);
if (number <= bits)
break;
}
bytes = i;
assert(i <= 4);
}
if(range <= 255) {
int i;
for (i = 1; i <= 8; i++) {
int bits = 1 << i;
if (range <= bits)
break;
}
return per_put_few_bits(po, number, i);
} else if(range == 256) {
bytes = 1;
} else if(range <= 65536) {
bytes = 2;
} else { /* Ranges > 64K */
int i;
for (i = 1; ; i++) {
int bits = 1 << (8 * i);
if (range <= bits)
break;
}
assert(i <= 4);
bytes = i;
}
if(aper_put_align(po) < 0) /* Aligning on octet */
return -1;
/* if(per_put_few_bits(po, bytes, 8))
return -1;
*/
return per_put_few_bits(po, number, 8 * bytes);
}
#else /* preserve old code base in case */
int
aper_put_nsnnwn(asn_per_outp_t *po, int dummy_range, int n) {
int bytes;
ASN_DEBUG("aper_put_nsnnwn");
if(n <= 63) {
if(n < 0) return -1;
return per_put_few_bits(po, n, 7);
}
if(n < 256)
bytes = 1;
else if(n < 65536)
bytes = 2;
else if(n < 256 * 65536)
bytes = 3;
else
return -1; /* This is not a "normally small" value */
if(per_put_few_bits(po, bytes, 8))
return -1;
return per_put_few_bits(po, n, 8 * bytes);
}
#endif /* which aper_put_nsnnwn() */
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