From a107bd201f836b1d82e1a9086a2a48625ac1c0dd Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Wed, 2 Mar 2022 13:52:42 -0800 Subject: [PATCH] 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. (cherry picked from commit b304fc201d2f6baf52ea790df8643e99772243cd) --- sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S | 7 +- sysdeps/x86_64/multiarch/memcmp-sse4.S | 9 ++- sysdeps/x86_64/multiarch/memcmp-ssse3.S | 7 +- sysdeps/x86_64/x32/Makefile | 4 +- sysdeps/x86_64/x32/tst-size_t-memcmp.c | 76 ++++++++++++++++++++ sysdeps/x86_64/x32/tst-size_t-wmemcmp.c | 20 ++++++ 6 files changed, 114 insertions(+), 9 deletions(-) create mode 100644 sysdeps/x86_64/x32/tst-size_t-memcmp.c create mode 100644 sysdeps/x86_64/x32/tst-size_t-wmemcmp.c diff --git a/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S b/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S index 30f764c3..e3a35b89 100644 --- a/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S +++ b/sysdeps/x86_64/multiarch/memcmp-avx2-movbe.S @@ -58,9 +58,12 @@ .section .text.avx,"ax",@progbits ENTRY (MEMCMP) # ifdef USE_AS_WMEMCMP - shl $2, %rdx + shl $2, %RDX_LP +# elif defined __ILP32__ + /* Clear the upper 32 bits. */ + movl %edx, %edx # endif - cmpq $VEC_SIZE, %rdx + cmp $VEC_SIZE, %RDX_LP jb L(less_vec) /* From VEC to 2 * VEC. No branch when size == VEC_SIZE. */ diff --git a/sysdeps/x86_64/multiarch/memcmp-sse4.S b/sysdeps/x86_64/multiarch/memcmp-sse4.S index 8e164f2c..302900f5 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 diff --git a/sysdeps/x86_64/multiarch/memcmp-ssse3.S b/sysdeps/x86_64/multiarch/memcmp-ssse3.S index 6f76c641..69d030fc 100644 --- a/sysdeps/x86_64/multiarch/memcmp-ssse3.S +++ b/sysdeps/x86_64/multiarch/memcmp-ssse3.S @@ -33,9 +33,12 @@ atom_text_section ENTRY (MEMCMP) # ifdef USE_AS_WMEMCMP - shl $2, %rdx - test %rdx, %rdx + shl $2, %RDX_LP + test %RDX_LP, %RDX_LP jz L(equal) +# elif defined __ILP32__ + /* Clear the upper 32 bits. */ + mov %edx, %edx # endif mov %rdx, %rcx mov %rdi, %rdx diff --git a/sysdeps/x86_64/x32/Makefile b/sysdeps/x86_64/x32/Makefile index 7d528889..ddec7f04 100644 --- a/sysdeps/x86_64/x32/Makefile +++ b/sysdeps/x86_64/x32/Makefile @@ -6,9 +6,9 @@ CFLAGS-s_llround.c += -fno-builtin-lround endif ifeq ($(subdir),string) -tests += tst-size_t-memchr +tests += tst-size_t-memchr tst-size_t-memcmp endif ifeq ($(subdir),wcsmbs) -tests += tst-size_t-wmemchr +tests += tst-size_t-wmemchr tst-size_t-wmemcmp endif diff --git a/sysdeps/x86_64/x32/tst-size_t-memcmp.c b/sysdeps/x86_64/x32/tst-size_t-memcmp.c new file mode 100644 index 00000000..9bd6fdb4 --- /dev/null +++ b/sysdeps/x86_64/x32/tst-size_t-memcmp.c @@ -0,0 +1,76 @@ +/* Test memcmp with size_t in the lower 32 bits of 64-bit register. + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#define TEST_MAIN +#ifdef WIDE +# define TEST_NAME "wmemcmp" +#else +# define TEST_NAME "memcmp" +#endif + +#include "test-size_t.h" + +#ifdef WIDE +# include +# include + +# define MEMCMP wmemcmp +# define CHAR wchar_t +#else +# define MEMCMP memcmp +# define CHAR char +#endif + +IMPL (MEMCMP, 1) + +typedef int (*proto_t) (const CHAR *, const CHAR *, size_t); + +static int +__attribute__ ((noinline, noclone)) +do_memcmp (parameter_t a, parameter_t b) +{ + return CALL (&b, a.p, b.p, a.len); +} + +static int +test_main (void) +{ + test_init (); + + parameter_t dest = { { page_size / sizeof (CHAR) }, buf1 }; + parameter_t src = { { 0 }, buf2 }; + + memcpy (buf1, buf2, page_size); + + int ret = 0; + FOR_EACH_IMPL (impl, 0) + { + src.fn = impl->fn; + int res = do_memcmp (dest, src); + if (res) + { + error (0, 0, "Wrong result in function %s: %i != 0", + impl->name, res); + ret = 1; + } + } + + return ret ? EXIT_FAILURE : EXIT_SUCCESS; +} + +#include diff --git a/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c b/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c new file mode 100644 index 00000000..e8b5ffd0 --- /dev/null +++ b/sysdeps/x86_64/x32/tst-size_t-wmemcmp.c @@ -0,0 +1,20 @@ +/* Test wmemcmp with size_t in the lower 32 bits of 64-bit register. + Copyright (C) 2019 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#define WIDE 1 +#include "tst-size_t-memcmp.c" -- GitLab