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Avoid accessing corrupted stack from __stack_chk_fail [BZ #21752] 

__libc_argv[0] points to address on stack and __libc_secure_getenv
accesses environment variables which are on stack.  We should avoid
accessing stack when stack is corrupted.

This patch also renames function argument in __fortify_fail_abort
from do_backtrace to need_backtrace to avoid confusion with do_backtrace
from enum __libc_message_action.

	[BZ #21752]
	* debug/fortify_fail.c (__fortify_fail_abort): Don't pass down
	__libc_argv[0] if we aren't doing backtrace.  Rename do_backtrace
	to need_backtrace.
	* sysdeps/posix/libc_fatal.c (__libc_message): Don't call
	__libc_secure_getenv if we aren't doing backtrace.
This commit is contained in:
H.J. Lu 2017-07-24 06:06:08 -07:00
parent 55703fcace
commit 422ff87c24
3 changed files with 27 additions and 9 deletions
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9
ChangeLog
View File

@ -1,3 +1,12 @@
2017-07-24 H.J. Lu <hongjiu.lu@intel.com>
[BZ #21752]
* debug/fortify_fail.c (__fortify_fail_abort): Don't pass down
__libc_argv[0] if we aren't doing backtrace. Rename do_backtrace
to need_backtrace.
* sysdeps/posix/libc_fatal.c (__libc_message): Don't call
__libc_secure_getenv if we aren't doing backtrace.
2017-07-24 Andreas Schwab <schwab@suse.de>
[BZ #21804]

12
debug/fortify_fail.c
View File

@ -24,13 +24,17 @@ extern char **__libc_argv attribute_hidden;
void
__attribute__ ((noreturn)) internal_function
__fortify_fail_abort (_Bool do_backtrace, const char *msg)
__fortify_fail_abort (_Bool need_backtrace, const char *msg)
{
/* The loop is added only to keep gcc happy. */
/* The loop is added only to keep gcc happy. Don't pass down
__libc_argv[0] if we aren't doing backtrace since __libc_argv[0]
may point to the corrupted stack. */
while (1)
__libc_message (do_backtrace ? (do_abort | do_backtrace) : do_abort,
__libc_message (need_backtrace ? (do_abort | do_backtrace) : do_abort,
"*** %s ***: %s terminated\n",
msg, __libc_argv[0] ?: "<unknown>");
msg,
(need_backtrace && __libc_argv[0] != NULL
? __libc_argv[0] : "<unknown>"));
}
void

15
sysdeps/posix/libc_fatal.c
View File

@ -75,11 +75,16 @@ __libc_message (enum __libc_message_action action, const char *fmt, ...)
FATAL_PREPARE;
#endif
/* Open a descriptor for /dev/tty unless the user explicitly
requests errors on standard error. */
const char *on_2 = __libc_secure_getenv ("LIBC_FATAL_STDERR_");
if (on_2 == NULL || *on_2 == '\0')
fd = open_not_cancel_2 (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
/* Don't call __libc_secure_getenv if we aren't doing backtrace, which
may access the corrupted stack. */
if ((action & do_backtrace))
{
/* Open a descriptor for /dev/tty unless the user explicitly
requests errors on standard error. */
const char *on_2 = __libc_secure_getenv ("LIBC_FATAL_STDERR_");
if (on_2 == NULL || *on_2 == '\0')
fd = open_not_cancel_2 (_PATH_TTY, O_RDWR | O_NOCTTY | O_NDELAY);
}
if (fd == -1)
fd = STDERR_FILENO;