From 65dcbd36711d15756289471b680fd46af4221f6f Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 21 Jan 2019 11:33:52 -0800 Subject: [PATCH 6/8] x86-64 strncmp family: 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 the strncmp family 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/strcmp-avx2.S: Use RDX_LP for length. * sysdeps/x86_64/multiarch/strcmp-sse42.S: Likewise. * sysdeps/x86_64/strcmp.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-strncasecmp, tst-size_t-strncmp and tst-size_t-wcsncmp. * sysdeps/x86_64/x32/tst-size_t-strncasecmp.c: New file. * sysdeps/x86_64/x32/tst-size_t-strncmp.c: Likewise. * sysdeps/x86_64/x32/tst-size_t-wcsncmp.c: Likewise. (cherry picked from commit ee915088a0231cd421054dbd8abab7aadf331153) --- sysdeps/x86_64/multiarch/strcmp-avx2.S | 6 +- sysdeps/x86_64/multiarch/strcmp-sse42.S | 6 +- sysdeps/x86_64/strcmp.S | 6 +- sysdeps/x86_64/x32/Makefile | 6 +- sysdeps/x86_64/x32/tst-size_t-strncasecmp.c | 59 ++++++++++++++++ sysdeps/x86_64/x32/tst-size_t-strncmp.c | 78 +++++++++++++++++++++ sysdeps/x86_64/x32/tst-size_t-wcsncmp.c | 20 ++++++ 7 files changed, 170 insertions(+), 11 deletions(-) create mode 100644 sysdeps/x86_64/x32/tst-size_t-strncasecmp.c create mode 100644 sysdeps/x86_64/x32/tst-size_t-strncmp.c create mode 100644 sysdeps/x86_64/x32/tst-size_t-wcsncmp.c diff --git a/sysdeps/x86_64/multiarch/strcmp-avx2.S b/sysdeps/x86_64/multiarch/strcmp-avx2.S index e8397f3b05..78fc116877 100644 --- a/sysdeps/x86_64/multiarch/strcmp-avx2.S +++ b/sysdeps/x86_64/multiarch/strcmp-avx2.S @@ -79,15 +79,15 @@ ENTRY (STRCMP) # ifdef USE_AS_STRNCMP /* Check for simple cases (0 or 1) in offset. */ - cmp $1, %rdx + cmp $1, %RDX_LP je L(char0) jb L(zero) # ifdef USE_AS_WCSCMP /* Convert units: from wide to byte char. */ - shl $2, %rdx + shl $2, %RDX_LP # endif /* Register %r11 tracks the maximum offset. */ - movq %rdx, %r11 + mov %RDX_LP, %R11_LP # endif movl %edi, %eax xorl %edx, %edx diff --git a/sysdeps/x86_64/multiarch/strcmp-sse42.S b/sysdeps/x86_64/multiarch/strcmp-sse42.S index d3c07bd292..a1ebea46fe 100644 --- a/sysdeps/x86_64/multiarch/strcmp-sse42.S +++ b/sysdeps/x86_64/multiarch/strcmp-sse42.S @@ -156,11 +156,11 @@ STRCMP_SSE42: #endif #if defined USE_AS_STRNCMP || defined USE_AS_STRNCASECMP_L - test %rdx, %rdx + test %RDX_LP, %RDX_LP je LABEL(strcmp_exitz) - cmp $1, %rdx + cmp $1, %RDX_LP je LABEL(Byte0) - mov %rdx, %r11 + mov %RDX_LP, %R11_LP #endif mov %esi, %ecx mov %edi, %eax diff --git a/sysdeps/x86_64/strcmp.S b/sysdeps/x86_64/strcmp.S index e16945b961..f47c8ad45c 100644 --- a/sysdeps/x86_64/strcmp.S +++ b/sysdeps/x86_64/strcmp.S @@ -135,11 +135,11 @@ ENTRY (STRCMP) * This implementation uses SSE to compare up to 16 bytes at a time. */ #if defined USE_AS_STRNCMP || defined USE_AS_STRNCASECMP_L - test %rdx, %rdx + test %RDX_LP, %RDX_LP je LABEL(strcmp_exitz) - cmp $1, %rdx + cmp $1, %RDX_LP je LABEL(Byte0) - mov %rdx, %r11 + mov %RDX_LP, %R11_LP #endif mov %esi, %ecx mov %edi, %eax diff --git a/sysdeps/x86_64/x32/Makefile b/sysdeps/x86_64/x32/Makefile index 98bd9ae9cd..db30283977 100644 --- a/sysdeps/x86_64/x32/Makefile +++ b/sysdeps/x86_64/x32/Makefile @@ -7,9 +7,11 @@ endif ifeq ($(subdir),string) tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \ - tst-size_t-memrchr tst-size_t-memset + tst-size_t-memrchr tst-size_t-memset tst-size_t-strncasecmp \ + tst-size_t-strncmp endif ifeq ($(subdir),wcsmbs) -tests += tst-size_t-wmemchr tst-size_t-wmemcmp tst-size_t-wmemset +tests += tst-size_t-wmemchr tst-size_t-wmemcmp tst-size_t-wmemset \ + tst-size_t-wcsncmp endif diff --git a/sysdeps/x86_64/x32/tst-size_t-strncasecmp.c b/sysdeps/x86_64/x32/tst-size_t-strncasecmp.c new file mode 100644 index 0000000000..862335937b --- /dev/null +++ b/sysdeps/x86_64/x32/tst-size_t-strncasecmp.c @@ -0,0 +1,59 @@ +/* Test strncaecmp 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_NAME "strncasecmp" +#include "test-size_t.h" + +IMPL (strncasecmp, 1) + +typedef int (*proto_t) (const char *, const char *, size_t); + +static int +__attribute__ ((noinline, noclone)) +do_strncasecmp (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 }, buf1 }; + parameter_t src = { { 0 }, buf2 }; + + strncpy ((char *) buf1, (const char *) buf2, page_size); + + int ret = 0; + FOR_EACH_IMPL (impl, 0) + { + src.fn = impl->fn; + int res = do_strncasecmp (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-strncmp.c b/sysdeps/x86_64/x32/tst-size_t-strncmp.c new file mode 100644 index 0000000000..54e6bd83ef --- /dev/null +++ b/sysdeps/x86_64/x32/tst-size_t-strncmp.c @@ -0,0 +1,78 @@ +/* Test strncmp 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 + . */ + +#ifdef WIDE +# define TEST_NAME "wcsncmp" +#else +# define TEST_NAME "strncmp" +#endif + +#include "test-size_t.h" + +#ifdef WIDE +# include + +# define STRNCMP wcsncmp +# define STRNCPY wcsncpy +# define CHAR wchar_t +#else +# define STRNCMP strncmp +# define STRNCPY strncpy +# define CHAR char +#endif + +IMPL (STRNCMP, 1) + +typedef int (*proto_t) (const CHAR *, const CHAR *, size_t); + + +static int +__attribute__ ((noinline, noclone)) +do_strncmp (parameter_t a, parameter_t b) +{ + return CALL (&b, a.p, b.p, a.len); +} + +static int +test_main (void) +{ + test_init (); + + size_t size = page_size / sizeof (CHAR); + parameter_t dest = { { size }, buf1 }; + parameter_t src = { { 0 }, buf2 }; + + STRNCPY ((CHAR *) buf1, (const CHAR *) buf2, size); + + int ret = 0; + FOR_EACH_IMPL (impl, 0) + { + src.fn = impl->fn; + int res = do_strncmp (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-wcsncmp.c b/sysdeps/x86_64/x32/tst-size_t-wcsncmp.c new file mode 100644 index 0000000000..4829647c19 --- /dev/null +++ b/sysdeps/x86_64/x32/tst-size_t-wcsncmp.c @@ -0,0 +1,20 @@ +/* Test wcsncmp 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-strncmp.c" -- 2.20.1