From ecd8b842cf37ea112e59cd9085ff1f1b6e208ae0 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 21 Jan 2019 11:29:58 -0800 Subject: x86-64 memrchr: 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 memrchr 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/memrchr.S: Use RDX_LP for length. * sysdeps/x86_64/multiarch/memrchr-avx2.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memrchr. * sysdeps/x86_64/x32/tst-size_t-memrchr.c: New file. --- sysdeps/x86_64/multiarch/memrchr-avx2.S | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'sysdeps/x86_64/multiarch') diff --git a/sysdeps/x86_64/multiarch/memrchr-avx2.S b/sysdeps/x86_64/multiarch/memrchr-avx2.S index 3c23bad7dd..e19a732396 100644 --- a/sysdeps/x86_64/multiarch/memrchr-avx2.S +++ b/sysdeps/x86_64/multiarch/memrchr-avx2.S @@ -32,10 +32,10 @@ ENTRY (__memrchr_avx2) vmovd %esi, %xmm0 vpbroadcastb %xmm0, %ymm0 - subq $VEC_SIZE, %rdx + sub $VEC_SIZE, %RDX_LP jbe L(last_vec_or_less) - addq %rdx, %rdi + add %RDX_LP, %RDI_LP /* Check the last VEC_SIZE bytes. */ vpcmpeqb (%rdi), %ymm0, %ymm1 -- cgit 1.4.1