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debug: make __read_chk a cancellation point (bug 29274) 

The __read_chk function, as the implementation behind the fortified read
function, must be a cancellation point, thus it cannot use INLINE_SYSCALL.
This commit is contained in:
Andreas Schwab 2022-06-22 13:16:30 +02:00
parent 2249ec60a9
commit dc30acf20b
3 changed files with 57 additions and 10 deletions
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7
debug/Makefile
View File

@ -110,6 +110,7 @@ CPPFLAGS-tst-longjmp_chk2.c += -D_FORTIFY_SOURCE=1
CFLAGS-tst-longjmp_chk3.c += -fexceptions -fasynchronous-unwind-tables
CPPFLAGS-tst-longjmp_chk3.c += -D_FORTIFY_SOURCE=1
CPPFLAGS-tst-realpath-chk.c += -D_FORTIFY_SOURCE=2
CPPFLAGS-tst-read-chk-cancel.c += -D_FORTIFY_SOURCE=2
# _FORTIFY_SOURCE tests.
# Auto-generate tests for _FORTIFY_SOURCE for different levels, compilers and
@ -204,6 +205,10 @@ ifeq ($(have-ssp),yes)
tests += tst-ssp-1
endif
ifeq ($(have-thread-library), yes)
tests += tst-read-chk-cancel
endif
ifeq (,$(CXX))
tests-unsupported = $(tests-cc-chk)
endif
@ -242,3 +247,5 @@ $(objpfx)xtrace: xtrace.sh
-e 's|@BINDIR@|$(bindir)|' -e 's|@PKGVERSION@|$(PKGVERSION)|' \
-e 's|@REPORT_BUGS_TO@|$(REPORT_BUGS_TO)|' $^ > $@.new \
&& rm -f $@ && mv $@.new $@ && chmod +x $@
$(objpfx)tst-read-chk-cancel: $(shared-thread-library)

10
debug/read_chk.c
View File

@ -16,12 +16,6 @@
<https://www.gnu.org/licenses/>. */
#include <unistd.h>
#include <sys/param.h>
#ifdef HAVE_INLINED_SYSCALLS
# include <errno.h>
# include <sysdep.h>
#endif
ssize_t
__read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
@ -29,9 +23,5 @@ __read_chk (int fd, void *buf, size_t nbytes, size_t buflen)
if (nbytes > buflen)
__chk_fail ();
#ifdef HAVE_INLINED_SYSCALLS
return INLINE_SYSCALL (read, 3, fd, buf, nbytes);
#else
return __read (fd, buf, nbytes);
#endif
}

50
debug/tst-read-chk-cancel.c Normal file
View File

@ -0,0 +1,50 @@
/* Test that __read_chk is a cancellation point (BZ #29274)
Copyright (C) 2022 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
<https://www.gnu.org/licenses/>. */
#include <stdint.h>
#include <support/xunistd.h>
#include <support/xthread.h>
static int pipe_fds[2];
static pthread_barrier_t barrier;
static void *
read_thread (void *n)
{
xpthread_barrier_wait (&barrier);
char c;
/* This call should be forwarded to __read_chk because the buffer size
is known, but the read length is non-constant. */
if (read (pipe_fds[0], &c, (uintptr_t) n) != 1)
return (void *) -1L;
return 0;
}
static int
do_test (void)
{
xpthread_barrier_init (&barrier, 0, 2);
xpipe (pipe_fds);
pthread_t thr = xpthread_create (0, read_thread, (void *) 1L);
xpthread_barrier_wait (&barrier);
xpthread_cancel (thr);
xpthread_join (thr);
return 0;
}
#include <support/test-driver.c>