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| author | H.J. Lu <hjl.tools@gmail.com> | 2019-02-01 12:17:09 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2019-02-01 15:32:53 -0800 |
| commit | bff8346b0184b15fbb80863112133f48a7bd62a9 (patch) | |
| tree | b0dcd6025eba0540bfb2019ab2a6b116a1bc8cc3 /sysdeps/x86_64/memchr.S | |
| parent | 7ab39c6a3cd4a61a2be3d2e6a2a56f4dccca9750 (diff) | |
| download | glibc-bff8346b0184b15fbb80863112133f48a7bd62a9.tar.gz glibc-bff8346b0184b15fbb80863112133f48a7bd62a9.tar.xz glibc-bff8346b0184b15fbb80863112133f48a7bd62a9.zip | |
x86-64 memchr/wmemchr: 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 memchr/wmemchr 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/memchr.S: Use RDX_LP for length. Clear the upper 32 bits of RDX register. * sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memchr and tst-size_t-wmemchr. * sysdeps/x86_64/x32/test-size_t.h: New file. * sysdeps/x86_64/x32/tst-size_t-memchr.c: Likewise. * sysdeps/x86_64/x32/tst-size_t-wmemchr.c: Likewise. (cherry picked from commit 97700a34f36721b11a754cf37a1cc40695ece1fd)
Diffstat (limited to 'sysdeps/x86_64/memchr.S')
| -rw-r--r-- | sysdeps/x86_64/memchr.S | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/sysdeps/x86_64/memchr.S b/sysdeps/x86_64/memchr.S index f5f05f6c8c..fd20f64f9b 100644 --- a/sysdeps/x86_64/memchr.S +++ b/sysdeps/x86_64/memchr.S @@ -34,12 +34,16 @@ ENTRY(MEMCHR) mov %edi, %ecx #ifdef USE_AS_WMEMCHR - test %rdx, %rdx + test %RDX_LP, %RDX_LP jz L(return_null) - shl $2, %rdx + shl $2, %RDX_LP #else +# ifdef __ILP32__ + /* Clear the upper 32 bits. */ + movl %edx, %edx +# endif punpcklbw %xmm1, %xmm1 - test %rdx, %rdx + test %RDX_LP, %RDX_LP jz L(return_null) punpcklbw %xmm1, %xmm1 #endif |