From ed421fca42fd9b4cab7c66e77894b8dd7ca57ed0 Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Tue, 11 Jul 2017 07:44:01 -0700 Subject: Avoid backtrace from __stack_chk_fail [BZ #12189] __stack_chk_fail is called on corrupted stack. Stack backtrace is very unreliable against corrupted stack. __libc_message is changed to accept enum __libc_message_action and call BEFORE_ABORT only if action includes do_backtrace. __fortify_fail_abort is added to avoid backtrace from __stack_chk_fail. [BZ #12189] * debug/Makefile (CFLAGS-tst-ssp-1.c): New. (tests): Add tst-ssp-1 if -fstack-protector works. * debug/fortify_fail.c: Include . (_fortify_fail_abort): New function. (__fortify_fail): Call _fortify_fail_abort. (__fortify_fail_abort): Add a hidden definition. * debug/stack_chk_fail.c: Include . (__stack_chk_fail): Call __fortify_fail_abort, instead of __fortify_fail. * debug/tst-ssp-1.c: New file. * include/stdio.h (__libc_message_action): New enum. (__libc_message): Replace int with enum __libc_message_action. (__fortify_fail_abort): New hidden prototype. * malloc/malloc.c (malloc_printerr): Update __libc_message calls. * sysdeps/posix/libc_fatal.c (__libc_message): Replace int with enum __libc_message_action. Call BEFORE_ABORT only if action includes do_backtrace. (__libc_fatal): Update __libc_message call. --- debug/Makefile | 6 ++++++ debug/fortify_fail.c | 15 +++++++++++++-- debug/stack_chk_fail.c | 3 ++- debug/tst-ssp-1.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 66 insertions(+), 3 deletions(-) create mode 100644 debug/tst-ssp-1.c (limited to 'debug') diff --git a/debug/Makefile b/debug/Makefile index cd4975c..c6d7872 100644 --- a/debug/Makefile +++ b/debug/Makefile @@ -139,12 +139,18 @@ LDFLAGS-tst-backtrace4 = -rdynamic LDFLAGS-tst-backtrace5 = -rdynamic LDFLAGS-tst-backtrace6 = -rdynamic +CFLAGS-tst-ssp-1.c = -fstack-protector + tests = backtrace-tst tst-longjmp_chk tst-chk1 tst-chk2 tst-chk3 \ tst-lfschk1 tst-lfschk2 tst-lfschk3 test-strcpy_chk test-stpcpy_chk \ tst-chk4 tst-chk5 tst-chk6 tst-lfschk4 tst-lfschk5 tst-lfschk6 \ tst-longjmp_chk2 tst-backtrace2 tst-backtrace3 tst-backtrace4 \ tst-backtrace5 tst-backtrace6 +ifeq ($(have-ssp),yes) +tests += tst-ssp-1 +endif + ifeq (,$(CXX)) tests-unsupported = tst-chk4 tst-chk5 tst-chk6 \ tst-lfschk4 tst-lfschk5 tst-lfschk6 diff --git a/debug/fortify_fail.c b/debug/fortify_fail.c index a31977a..c90d384 100644 --- a/debug/fortify_fail.c +++ b/debug/fortify_fail.c @@ -17,17 +17,28 @@ #include #include +#include extern char **__libc_argv attribute_hidden; void __attribute__ ((noreturn)) internal_function -__fortify_fail (const char *msg) +__fortify_fail_abort (_Bool do_backtrace, const char *msg) { /* The loop is added only to keep gcc happy. */ while (1) - __libc_message (2, "*** %s ***: %s terminated\n", + __libc_message (do_backtrace ? (do_abort | do_backtrace) : do_abort, + "*** %s ***: %s terminated\n", msg, __libc_argv[0] ?: ""); } + +void +__attribute__ ((noreturn)) internal_function +__fortify_fail (const char *msg) +{ + __fortify_fail_abort (true, msg); +} + libc_hidden_def (__fortify_fail) +libc_hidden_def (__fortify_fail_abort) diff --git a/debug/stack_chk_fail.c b/debug/stack_chk_fail.c index 4f73464..9ab9bc7 100644 --- a/debug/stack_chk_fail.c +++ b/debug/stack_chk_fail.c @@ -17,6 +17,7 @@ #include #include +#include extern char **__libc_argv attribute_hidden; @@ -25,7 +26,7 @@ void __attribute__ ((noreturn)) __stack_chk_fail (void) { - __fortify_fail ("stack smashing detected"); + __fortify_fail_abort (false, "stack smashing detected"); } strong_alias (__stack_chk_fail, __stack_chk_fail_local) diff --git a/debug/tst-ssp-1.c b/debug/tst-ssp-1.c new file mode 100644 index 0000000..52c67e2 --- /dev/null +++ b/debug/tst-ssp-1.c @@ -0,0 +1,45 @@ +/* Verify that __stack_chk_fail won't segfault. + Copyright (C) 2017 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 + . */ + +/* Based on gcc.dg/ssp-1.c from GCC testsuite. */ + +#include + +static void +__attribute__ ((noinline, noclone)) +test (char *foo) +{ + int i; + + /* smash stack */ + for (i = 0; i <= 400; i++) + foo[i] = 42; +} + +static int +do_test (void) +{ + char foo[30]; + + test (foo); + + return 1; /* fail */ +} + +#define EXPECTED_SIGNAL SIGABRT +#include -- cgit v1.1