Message ID | 20170711132509.GA3054@gmail.com |
---|---|
State | New |
Headers | show |
On 11/07/2017 10:25, H.J. Lu wrote: > On Tue, Jul 11, 2017 at 10:49:04AM +0200, Florian Weimer wrote: >> * H. J. Lu: >> >>> __stack_chk_fail is called on corrupted stack. __stack_chk_fail should >>> use as little stack as possible. __libc_message is extended to avoid >>> calling BEFORE_ABORT when do_abort >= 3 and __fortify_fail_abort is >>> added to avoid backtrace from __stack_chk_fail. >>> >>> OK for master? >> >> I think you should use an enum for do_abort and avoid the magic >> numbers. > > Done. > >> >> Could you post an example of the new output? > > [hjl@gnu-tools-1 debug]$ ./tst-ssp-1 > *** stack smashing detected ***: ./tst-ssp-1 terminated > (gdb) r --direct > Starting program: /export/build/gnu/glibc/build-x86_64-linux/debug/tst-ssp-1 --direct > *** stack smashing detected ***: /export/build/gnu/glibc/build-x86_64-linux/debug/tst-ssp-1 terminated > > Program received signal SIGABRT, Aborted. > __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 > 51 } > (gdb) bt > #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51 > #1 0x00007ffff7a5e4e5 in __GI_abort () at abort.c:90 > #2 0x00007ffff7a9db98 in __libc_message (action=action@entry=do_abort, > fmt=fmt@entry=0x7ffff7b9d0c2 "*** %s ***: %s terminated\n") > at ../sysdeps/posix/libc_fatal.c:176 > #3 0x00007ffff7b29a57 in __GI___fortify_fail_abort ( > do_backtrace=do_backtrace@entry=false, > msg=msg@entry=0x7ffff7b9d0aa "stack smashing detected") > at fortify_fail.c:31 > #4 0x00007ffff7b29a12 in __stack_chk_fail () at stack_chk_fail.c:29 > #5 0x000000000040138b in do_test () at tst-ssp-1.c:42 > #6 0x2a2a2a2a2a2a2a2a in ?? () <<<< Stack is corrupted > #7 0x2a2a2a2a2a2a2a2a in ?? () > #8 0x2a2a2a2a2a2a2a2a in ?? () > #9 0x2a2a2a2a2a2a2a2a in ?? () > > > Here is the updated patch. OK for master? LGTM. > > > H.J. > --- > __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 <stdbool.h>. > (_fortify_fail_abort): New function. > (__fortify_fail): Call _fortify_fail_abort. > (__fortify_fail_abort): Add a hidden definition. > * debug/stack_chk_fail.c: Include <stdbool.h>. > (__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 +++++++++++++++++++++++++++++++++++++++++++++ > include/stdio.h | 13 ++++++++++++- > malloc/malloc.c | 6 ++++-- > sysdeps/posix/libc_fatal.c | 11 ++++++----- > 7 files changed, 88 insertions(+), 11 deletions(-) > create mode 100644 debug/tst-ssp-1.c > > 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 <stdio.h> > #include <stdlib.h> > +#include <stdbool.h> > > > 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] ?: "<unknown>"); > } > + > +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 120d269..4b099b5 100644 > --- a/debug/stack_chk_fail.c > +++ b/debug/stack_chk_fail.c > @@ -17,6 +17,7 @@ > > #include <stdio.h> > #include <stdlib.h> > +#include <stdbool.h> > > > 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"); > } > > #ifdef SHARED > 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 > + <http://www.gnu.org/licenses/>. */ > + > +/* Based on gcc.dg/ssp-1.c from GCC testsuite. */ > + > +#include <signal.h> > + > +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 <support/test-driver.c> > diff --git a/include/stdio.h b/include/stdio.h > index f68f633..215f919 100644 > --- a/include/stdio.h > +++ b/include/stdio.h > @@ -86,13 +86,24 @@ extern int __gen_tempname (char *__tmpl, int __suffixlen, int __flags, > # define __GT_DIR 1 /* create a directory */ > # define __GT_NOCREATE 2 /* just find a name not currently in use */ > > +enum __libc_message_action > +{ > + do_message = 0, /* Print message. */ > + do_abort = 1 << 0, /* Abort. */ > + do_backtrace = 1 << 1 /* Backtrace. */ > +}; > + > /* Print out MESSAGE on the error output and abort. */ > extern void __libc_fatal (const char *__message) > __attribute__ ((__noreturn__)); > -extern void __libc_message (int do_abort, const char *__fnt, ...); > +extern void __libc_message (enum __libc_message_action action, > + const char *__fnt, ...); > extern void __fortify_fail (const char *msg) > __attribute__ ((__noreturn__)) internal_function; > +extern void __fortify_fail_abort (_Bool, const char *msg) > + __attribute__ ((__noreturn__)) internal_function; > libc_hidden_proto (__fortify_fail) > +libc_hidden_proto (__fortify_fail_abort) > > /* Acquire ownership of STREAM. */ > extern void __flockfile (FILE *__stream); > diff --git a/malloc/malloc.c b/malloc/malloc.c > index 2527e25..54e406b 100644 > --- a/malloc/malloc.c > +++ b/malloc/malloc.c > @@ -5397,7 +5397,8 @@ malloc_printerr (int action, const char *str, void *ptr, mstate ar_ptr) > set_arena_corrupt (ar_ptr); > > if ((action & 5) == 5) > - __libc_message (action & 2, "%s\n", str); > + __libc_message ((action & 2) ? (do_abort | do_backtrace) : do_message, > + "%s\n", str); > else if (action & 1) > { > char buf[2 * sizeof (uintptr_t) + 1]; > @@ -5407,7 +5408,8 @@ malloc_printerr (int action, const char *str, void *ptr, mstate ar_ptr) > while (cp > buf) > *--cp = '0'; > > - __libc_message (action & 2, "*** Error in `%s': %s: 0x%s ***\n", > + __libc_message ((action & 2) ? (do_abort | do_backtrace) : do_message, > + "*** Error in `%s': %s: 0x%s ***\n", > __libc_argv[0] ? : "<unknown>", str, cp); > } > else if (action & 2) > diff --git a/sysdeps/posix/libc_fatal.c b/sysdeps/posix/libc_fatal.c > index b261963..25af8bd 100644 > --- a/sysdeps/posix/libc_fatal.c > +++ b/sysdeps/posix/libc_fatal.c > @@ -64,7 +64,7 @@ struct str_list > > /* Abort with an error message. */ > void > -__libc_message (int do_abort, const char *fmt, ...) > +__libc_message (enum __libc_message_action action, const char *fmt, ...) > { > va_list ap; > int fd = -1; > @@ -140,7 +140,7 @@ __libc_message (int do_abort, const char *fmt, ...) > > written = WRITEV_FOR_FATAL (fd, iov, nlist, total); > > - if (do_abort) > + if ((action & do_abort)) > { > total = ((total + 1 + GLRO(dl_pagesize) - 1) > & ~(GLRO(dl_pagesize) - 1)); > @@ -167,9 +167,10 @@ __libc_message (int do_abort, const char *fmt, ...) > > va_end (ap); > > - if (do_abort) > + if ((action & do_abort)) > { > - BEFORE_ABORT (do_abort, written, fd); > + if ((action & do_backtrace)) > + BEFORE_ABORT (do_abort, written, fd); > > /* Kill the application. */ > abort (); > @@ -182,6 +183,6 @@ __libc_fatal (const char *message) > { > /* The loop is added only to keep gcc happy. */ > while (1) > - __libc_message (1, "%s", message); > + __libc_message (do_abort | do_backtrace, "%s", message); > } > libc_hidden_def (__libc_fatal) >
* H. J. Lu:
> +CFLAGS-tst-ssp-1.c = -fstack-protector
This should be -fstack-protector-all, in case the the stack protector
heuristics do not instrument a thirty-byte array.
On Tue, Jul 11, 2017 at 12:39 PM, Florian Weimer <fw@deneb.enyo.de> wrote: > * H. J. Lu: > >> +CFLAGS-tst-ssp-1.c = -fstack-protector > > This should be -fstack-protector-all, in case the the stack protector > heuristics do not instrument a thirty-byte array. Does GCC 4.9 support -fstack-protector-all?
* H. J. Lu: > On Tue, Jul 11, 2017 at 12:39 PM, Florian Weimer <fw@deneb.enyo.de> wrote: >> * H. J. Lu: >> >>> +CFLAGS-tst-ssp-1.c = -fstack-protector >> >> This should be -fstack-protector-all, in case the the stack protector >> heuristics do not instrument a thirty-byte array. > > Does GCC 4.9 support -fstack-protector-all? It's mentioned in <https://gcc.gnu.org/onlinedocs/gcc-4.4.2/gcc/Optimize-Options.html> so I assume it does. (-fstack-protector-strong is the recent addition.)
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 <stdio.h> #include <stdlib.h> +#include <stdbool.h> 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] ?: "<unknown>"); } + +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 120d269..4b099b5 100644 --- a/debug/stack_chk_fail.c +++ b/debug/stack_chk_fail.c @@ -17,6 +17,7 @@ #include <stdio.h> #include <stdlib.h> +#include <stdbool.h> 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"); } #ifdef SHARED 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 + <http://www.gnu.org/licenses/>. */ + +/* Based on gcc.dg/ssp-1.c from GCC testsuite. */ + +#include <signal.h> + +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 <support/test-driver.c> diff --git a/include/stdio.h b/include/stdio.h index f68f633..215f919 100644 --- a/include/stdio.h +++ b/include/stdio.h @@ -86,13 +86,24 @@ extern int __gen_tempname (char *__tmpl, int __suffixlen, int __flags, # define __GT_DIR 1 /* create a directory */ # define __GT_NOCREATE 2 /* just find a name not currently in use */ +enum __libc_message_action +{ + do_message = 0, /* Print message. */ + do_abort = 1 << 0, /* Abort. */ + do_backtrace = 1 << 1 /* Backtrace. */ +}; + /* Print out MESSAGE on the error output and abort. */ extern void __libc_fatal (const char *__message) __attribute__ ((__noreturn__)); -extern void __libc_message (int do_abort, const char *__fnt, ...); +extern void __libc_message (enum __libc_message_action action, + const char *__fnt, ...); extern void __fortify_fail (const char *msg) __attribute__ ((__noreturn__)) internal_function; +extern void __fortify_fail_abort (_Bool, const char *msg) + __attribute__ ((__noreturn__)) internal_function; libc_hidden_proto (__fortify_fail) +libc_hidden_proto (__fortify_fail_abort) /* Acquire ownership of STREAM. */ extern void __flockfile (FILE *__stream); diff --git a/malloc/malloc.c b/malloc/malloc.c index 2527e25..54e406b 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -5397,7 +5397,8 @@ malloc_printerr (int action, const char *str, void *ptr, mstate ar_ptr) set_arena_corrupt (ar_ptr); if ((action & 5) == 5) - __libc_message (action & 2, "%s\n", str); + __libc_message ((action & 2) ? (do_abort | do_backtrace) : do_message, + "%s\n", str); else if (action & 1) { char buf[2 * sizeof (uintptr_t) + 1]; @@ -5407,7 +5408,8 @@ malloc_printerr (int action, const char *str, void *ptr, mstate ar_ptr) while (cp > buf) *--cp = '0'; - __libc_message (action & 2, "*** Error in `%s': %s: 0x%s ***\n", + __libc_message ((action & 2) ? (do_abort | do_backtrace) : do_message, + "*** Error in `%s': %s: 0x%s ***\n", __libc_argv[0] ? : "<unknown>", str, cp); } else if (action & 2) diff --git a/sysdeps/posix/libc_fatal.c b/sysdeps/posix/libc_fatal.c index b261963..25af8bd 100644 --- a/sysdeps/posix/libc_fatal.c +++ b/sysdeps/posix/libc_fatal.c @@ -64,7 +64,7 @@ struct str_list /* Abort with an error message. */ void -__libc_message (int do_abort, const char *fmt, ...) +__libc_message (enum __libc_message_action action, const char *fmt, ...) { va_list ap; int fd = -1; @@ -140,7 +140,7 @@ __libc_message (int do_abort, const char *fmt, ...) written = WRITEV_FOR_FATAL (fd, iov, nlist, total); - if (do_abort) + if ((action & do_abort)) { total = ((total + 1 + GLRO(dl_pagesize) - 1) & ~(GLRO(dl_pagesize) - 1)); @@ -167,9 +167,10 @@ __libc_message (int do_abort, const char *fmt, ...) va_end (ap); - if (do_abort) + if ((action & do_abort)) { - BEFORE_ABORT (do_abort, written, fd); + if ((action & do_backtrace)) + BEFORE_ABORT (do_abort, written, fd); /* Kill the application. */ abort (); @@ -182,6 +183,6 @@ __libc_fatal (const char *message) { /* The loop is added only to keep gcc happy. */ while (1) - __libc_message (1, "%s", message); + __libc_message (do_abort | do_backtrace, "%s", message); } libc_hidden_def (__libc_fatal)