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recipes-devtools: fix segfault in lib32-gcc with "." multilib_dir 

When enabling a lib32-gcc in a 64 bit build, without doing any
other configuration, the mutilib dir is unspecified, which is
represented internally in gcc as "." and as such uncovers an
invalid free on a non-malloc'd pointer.

As suggested by the gcc folks, simply make sure the "." case
is also stored in a malloc'd pointer, so that the intended
runtime behaviour of the code remains unchanged.

Patch has been accepted by upstream maintainers of gcc.

(From OE-Core rev: bf1473d0c1b099b8d919835cc430b99606134aab)

Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
This commit is contained in:
Paul Gortmaker 2014-06-26 15:08:47 -04:00 committed by Richard Purdie
parent 184dddfb9a
commit 0ae5aadc6b
2 changed files with 67 additions and 0 deletions
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1
meta/recipes-devtools/gcc/gcc-4.9.inc
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@ -66,6 +66,7 @@ SRC_URI = "${GNU_MIRROR}/gcc/gcc-${PV}/gcc-${PV}.tar.bz2 \
file://0050-Revert-Use-dbx_reg_number-for-spanning-registers.patch \
file://0051-eabispe.patch \
file://0052-Fix-GCC-targeting-E500-SPE-errors-with-the-_Decimal64-type.patch \
file://0053-gcc-fix-segfault-from-calling-free-on-non-malloc-d-a.patch \
"
SRC_URI[md5sum] = "9709b49ae0e904cbb0a6a1b62853b556"
SRC_URI[sha256sum] = "b9b047a97bade9c1c89970bc8e211ff57b7b8998a1730a80a653d329f8ed1257"

66
meta/recipes-devtools/gcc/gcc-4.9/0053-gcc-fix-segfault-from-calling-free-on-non-malloc-d-a.patch Normal file
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@ -0,0 +1,66 @@
From a22a222c8f9299f6c07a0274388ade7d4ab8c28d Mon Sep 17 00:00:00 2001
From: Paul Gortmaker <paul.gortmaker@windriver.com>
Date: Fri, 20 Jun 2014 16:41:08 -0400
Subject: [PATCH] gcc: fix segfault from calling free on non-malloc'd area
We see the following on a 32bit gcc installed on 64 bit host:
Reading symbols from ./i586-pokymllib32-linux-gcc...done.
(gdb) run
Starting program: x86-pokymllib32-linux/lib32-gcc/4.9.0-r0/image/usr/bin/i586-pokymllib32-linux-gcc
Program received signal SIGSEGV, Segmentation fault.
0xf7e957e0 in free () from /lib/i386-linux-gnu/libc.so.6
(gdb) bt
#0 0xf7e957e0 in free () from /lib/i386-linux-gnu/libc.so.6
#1 0x0804b73c in set_multilib_dir () at gcc-4.9.0/gcc/gcc.c:7827
#2 main (argc=1, argv=0xffffd504) at gcc-4.9.0/gcc/gcc.c:6688
(gdb)
The problem arises because we conditionally assign the pointer we
eventually free, and the conditional may assign the pointer to the
non-malloc'd internal string "." which fails when we free it here:
if (multilib_dir == NULL && multilib_os_dir != NULL
&& strcmp (multilib_os_dir, ".") == 0)
{
free (CONST_CAST (char *, multilib_os_dir));
...
As suggested by Jakub, ensure the "." case is also malloc'd via
xstrdup() and hence the pointer for the "." case can be freed.
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Jeff Law <law@redhat.com>
Cc: Matthias Klose <doko@ubuntu.com>
CC: Tobias Burnus <burnus@net-b.de>
Upstream-Status: Accepted [ https://gcc.gnu.org/ml/gcc-patches/2014-06/msg02069.html ]
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
diff --git a/gcc/gcc.c b/gcc/gcc.c
index 9ac18e60d801..168acf7eb0c9 100644
--- a/gcc/gcc.c
+++ b/gcc/gcc.c
@@ -7790,10 +7790,15 @@ set_multilib_dir (void)
q2++;
if (*q2 == ':')
ml_end = q2;
- new_multilib_os_dir = XNEWVEC (char, ml_end - q);
- memcpy (new_multilib_os_dir, q + 1, ml_end - q - 1);
- new_multilib_os_dir[ml_end - q - 1] = '\0';
- multilib_os_dir = *new_multilib_os_dir ? new_multilib_os_dir : ".";
+ if (ml_end - q == 1)
+ multilib_os_dir = xstrdup (".");
+ else
+ {
+ new_multilib_os_dir = XNEWVEC (char, ml_end - q);
+ memcpy (new_multilib_os_dir, q + 1, ml_end - q - 1);
+ new_multilib_os_dir[ml_end - q - 1] = '\0';
+ multilib_os_dir = new_multilib_os_dir;
+ }
if (q2 < end && *q2 == ':')
{
--
1.9.2