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| author | H.J. Lu <hjl.tools@gmail.com> | 2019-01-21 11:25:56 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2019-01-21 11:26:07 -0800 |
| commit | b304fc201d2f6baf52ea790df8643e99772243cd (patch) | |
| tree | 502227813e790ba46c8f6e4ee826cb3f36ffb9bb /sysdeps/x86_64/multiarch/memcmp-sse4.S | |
| parent | 97700a34f36721b11a754cf37a1cc40695ece1fd (diff) | |
| download | glibc-b304fc201d2f6baf52ea790df8643e99772243cd.tar.gz glibc-b304fc201d2f6baf52ea790df8643e99772243cd.tar.xz glibc-b304fc201d2f6baf52ea790df8643e99772243cd.zip | |
x86-64 memcmp/wmemcmp: Properly handle the length parameter [BZ# 24097]
On x32, the size_t parameter may be passed in the lower 32 bits of a 64-bit register with the non-zero upper 32 bits. The string/memory functions written in assembly can only use the lower 32 bits of a 64-bit register as length or must clear the upper 32 bits before using the full 64-bit register for length. This pach fixes memcmp/wmemcmp for x32. Tested on x86-64 and x32. On x86-64, libc.so is the same with and withou the fix. [BZ# 24097] CVE-2019-6488 * sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S: Use RDX_LP for length. Clear the upper 32 bits of RDX register. * sysdeps/x86_64/multiarch/memcmp-sse4.S: Likewise. * sysdeps/x86_64/multiarch/memcmp-ssse3.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memcmp and tst-size_t-wmemcmp. * sysdeps/x86_64/x32/tst-size_t-memcmp.c: New file. * sysdeps/x86_64/x32/tst-size_t-wmemcmp.c: Likewise.
Diffstat (limited to 'sysdeps/x86_64/multiarch/memcmp-sse4.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/memcmp-sse4.S | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S index 789ff15e2c..c8f67318a4 100644 --- a/sysdeps/x86_64/multiarch/memcmp-sse4.S +++ b/sysdeps/x86_64/multiarch/memcmp-sse4.S @@ -42,13 +42,16 @@ .section .text.sse4.1,"ax",@progbits ENTRY (MEMCMP) # ifdef USE_AS_WMEMCMP - shl $2, %rdx + shl $2, %RDX_LP +# elif defined __ILP32__ + /* Clear the upper 32 bits. */ + mov %edx, %edx # endif pxor %xmm0, %xmm0 - cmp $79, %rdx + cmp $79, %RDX_LP ja L(79bytesormore) # ifndef USE_AS_WMEMCMP - cmp $1, %rdx + cmp $1, %RDX_LP je L(firstbyte) # endif add %rdx, %rsi |