diff options
Diffstat (limited to 'gnu/packages/patches/glibc-memchr-overflow-i686.patch')
| -rw-r--r-- | gnu/packages/patches/glibc-memchr-overflow-i686.patch | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/gnu/packages/patches/glibc-memchr-overflow-i686.patch b/gnu/packages/patches/glibc-memchr-overflow-i686.patch new file mode 100644 index 0000000000..0b1b5b9f96 --- /dev/null +++ b/gnu/packages/patches/glibc-memchr-overflow-i686.patch @@ -0,0 +1,74 @@ +Extracted from glibc upstream git repository. Changes to the ChangeLog have +been removed. This patch is needed to fix spurious segmentation faults on +i686. + +From 3abeeec5f46ff036bd9df60bb096e20314ccd078 Mon Sep 17 00:00:00 2001 +From: Adhemerval Zanella <adhemerval.zanella@linaro.org> +Date: Tue, 14 Mar 2017 14:16:13 -0300 +Subject: [PATCH] Fix i686 memchr overflow calculation (BZ#21182) + +This patch fixes the regression added by 23d2770 for final address +overflow calculation. The subtraction of the considered size (16) +at line 120 is at wrong place, for sizes less than 16 subsequent +overflow check will not take in consideration an invalid size (since +the subtraction will be negative). Also, the lea instruction also +does not raise the carry flag (CF) that is used in subsequent jbe +to check for overflow. + +The fix is to follow x86_64 logic from 3daef2c where the overflow +is first check and a sub instruction is issued. In case of resulting +negative size, CF will be set by the sub instruction and a NULL +result will be returned. The patch also add similar tests reported +in bug report. + +Checked on i686-linux-gnu and x86_64-linux-gnu. + + * string/test-memchr.c (do_test): Add BZ#21182 checks for address + near end of a page. + * sysdeps/i386/i686/multiarch/memchr-sse2.S (__memchr): Fix + overflow calculation. +--- + string/test-memchr.c | 6 ++++++ + sysdeps/i386/i686/multiarch/memchr-sse2.S | 2 +- + 3 files changed, 15 insertions(+), 1 deletion(-) + +diff --git a/string/test-memchr.c b/string/test-memchr.c +index 2403c9242b..669e092e7d 100644 +--- a/string/test-memchr.c ++++ b/string/test-memchr.c +@@ -210,6 +210,12 @@ test_main (void) + do_test (0, i, i + 1, i + 1, 0); + } + ++ /* BZ#21182 - wrong overflow calculation for i686 implementation ++ with address near end of the page. */ ++ for (i = 2; i < 16; ++i) ++ /* page_size is in fact getpagesize() * 2. */ ++ do_test (page_size / 2 - i, i, i, 1, 0x9B); ++ + do_random_tests (); + return ret; + } +diff --git a/sysdeps/i386/i686/multiarch/memchr-sse2.S b/sysdeps/i386/i686/multiarch/memchr-sse2.S +index 910679cfc0..e41f324a77 100644 +--- a/sysdeps/i386/i686/multiarch/memchr-sse2.S ++++ b/sysdeps/i386/i686/multiarch/memchr-sse2.S +@@ -117,7 +117,6 @@ L(crosscache): + + # ifndef USE_AS_RAWMEMCHR + jnz L(match_case2_prolog1) +- lea -16(%edx), %edx + /* Calculate the last acceptable address and check for possible + addition overflow by using satured math: + edx = ecx + edx +@@ -125,6 +124,7 @@ L(crosscache): + add %ecx, %edx + sbb %eax, %eax + or %eax, %edx ++ sub $16, %edx + jbe L(return_null) + lea 16(%edi), %edi + # else +-- +2.12.2 + |