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authorFlorian Weimer <fweimer@redhat.com>2018-01-04 18:00:05 +0100
committerFlorian Weimer <fweimer@redhat.com>2018-01-04 18:47:35 +0100
commit8a5df95ffa83f525a4f638ead743f4fa2b7fe45a (patch)
treee31a8752224edc6c29d9017685dbea5c215d3254
parent82eef55f8fad3e00c53050de5d6ebea08df488b3 (diff)
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i386: In makecontext, align the stack before calling exit [BZ #22667]
Before this change, if glibc was compiled with SSE instructions and a sufficiently recent GCC, an unaligned stack access in __run_exit_handlers would cause stdlib/tst-makecontext to crash.
-rw-r--r--ChangeLog8
-rw-r--r--stdlib/Makefile3
-rw-r--r--stdlib/tst-makecontext-align.c241
-rw-r--r--sysdeps/unix/sysv/linux/i386/makecontext.S14
4 files changed, 263 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog
index 7f0c2ebb0e..5be91cf978 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,13 @@
2018-01-04 Florian Weimer <fweimer@redhat.com>
+ [BZ #22667]
+ * sysdeps/unix/sysv/linux/i386/makecontext.S (__makecontext):
+ Align the stack before calling exit.
+ * stdlib/tst-makecontext-align.c: New file.
+ * stdlib/Makefile (tests): Add tst-makecontext-align.
+
+2018-01-04 Florian Weimer <fweimer@redhat.com>
+
Add support for calling dlvsym from libc.so.
* include/dlfcn.h (__libc_dlvsym): Declare.
* elf/Makefile (tests-static-internal): Add
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 691325b91b..7c363a6e4d 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -83,7 +83,8 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
tst-getrandom tst-atexit tst-at_quick_exit \
tst-cxa_atexit tst-on_exit test-atexit-race \
test-at_quick_exit-race test-cxa_atexit-race \
- test-on_exit-race test-dlclose-exit-race
+ test-on_exit-race test-dlclose-exit-race \
+ tst-makecontext-align
tests-internal := tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \
tst-tls-atexit tst-tls-atexit-nodelete
diff --git a/stdlib/tst-makecontext-align.c b/stdlib/tst-makecontext-align.c
new file mode 100644
index 0000000000..82394b4f6b
--- /dev/null
+++ b/stdlib/tst-makecontext-align.c
@@ -0,0 +1,241 @@
+/* Check stack alignment provided by makecontext.
+ Copyright (C) 2018 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/>. */
+
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <support/check.h>
+#include <support/namespace.h>
+#include <support/xunistd.h>
+#include <sys/mman.h>
+#include <ucontext.h>
+
+/* Used for error reporting. */
+static const char *context;
+
+/* Check that ADDRESS is aligned to ALIGNMENT bytes, behind a compiler
+ barrier. */
+__attribute__ ((noinline, noclone, weak))
+void
+check_align (void *address, size_t alignment)
+{
+ uintptr_t uaddress = (uintptr_t) address;
+ if ((uaddress % alignment) != 0)
+ {
+ support_record_failure ();
+ printf ("error: %s: object at address %p is not aligned to %zu bytes\n",
+ context, address, alignment);
+ }
+}
+
+/* Various alignment checking functions. */
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_int (void)
+{
+ int a;
+ check_align (&a, __alignof__ (a));
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_long (void)
+{
+ long a;
+ check_align (&a, __alignof__ (a));
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_long_long (void)
+{
+ long long a;
+ check_align (&a, __alignof__ (a));
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_double (void)
+{
+ double a;
+ check_align (&a, __alignof__ (a));
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_4 (void)
+{
+ int a __attribute__ ((aligned (4)));
+ check_align (&a, 4);
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_8 (void)
+{
+ double a __attribute__ ((aligned (8)));
+ check_align (&a, 8);
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_16 (void)
+{
+ struct aligned
+ {
+ double x0 __attribute__ ((aligned (16)));
+ double x1;
+ } a;
+ check_align (&a, 16);
+}
+
+__attribute__ ((noinline, noclone, weak))
+void
+check_align_32 (void)
+{
+ struct aligned
+ {
+ double x0 __attribute__ ((aligned (32)));
+ double x1;
+ double x2;
+ double x3;
+ } a;
+ check_align (&a, 32);
+}
+
+/* Call all the alignment checking functions. */
+__attribute__ ((noinline, noclone, weak))
+void
+check_alignments (void)
+{
+ check_align_int ();
+ check_align_long ();
+ check_align_long_long ();
+ check_align_double ();
+ check_align_4 ();
+ check_align_8 ();
+ check_align_16 ();
+ check_align_32 ();
+}
+
+/* Callback functions for makecontext and their invokers (to be used
+ with support_isolate_in_subprocess). */
+
+static ucontext_t ucp;
+
+static void
+callback_0 (void)
+{
+ context = "callback_0";
+ check_alignments ();
+ context = "after return from callback_0";
+}
+
+static void
+invoke_callback_0 (void *closure)
+{
+ makecontext (&ucp, (void *) callback_0, 0);
+ if (setcontext (&ucp) != 0)
+ FAIL_EXIT1 ("setcontext");
+ FAIL_EXIT1 ("setcontext returned");
+}
+
+static void
+callback_1 (int arg1)
+{
+ context = "callback_1";
+ check_alignments ();
+ TEST_COMPARE (arg1, 101);
+ context = "after return from callback_1";
+}
+
+static void
+invoke_callback_1 (void *closure)
+{
+ makecontext (&ucp, (void *) callback_1, 1, 101);
+ if (setcontext (&ucp) != 0)
+ FAIL_EXIT1 ("setcontext");
+ FAIL_EXIT1 ("setcontext returned");
+}
+
+static void
+callback_2 (int arg1, int arg2)
+{
+ context = "callback_2";
+ check_alignments ();
+ TEST_COMPARE (arg1, 201);
+ TEST_COMPARE (arg2, 202);
+ context = "after return from callback_2";
+}
+
+static void
+invoke_callback_2 (void *closure)
+{
+ makecontext (&ucp, (void *) callback_2, 2, 201, 202);
+ if (setcontext (&ucp) != 0)
+ FAIL_EXIT1 ("setcontext");
+ FAIL_EXIT1 ("setcontext returned");
+}
+
+static void
+callback_3 (int arg1, int arg2, int arg3)
+{
+ context = "callback_3";
+ check_alignments ();
+ TEST_COMPARE (arg1, 301);
+ TEST_COMPARE (arg2, 302);
+ TEST_COMPARE (arg3, 303);
+ context = "after return from callback_3";
+}
+
+static void
+invoke_callback_3 (void *closure)
+{
+ makecontext (&ucp, (void *) callback_3, 3, 301, 302, 303);
+ if (setcontext (&ucp) != 0)
+ FAIL_EXIT1 ("setcontext");
+ FAIL_EXIT1 ("setcontext returned");
+}
+
+static int
+do_test (void)
+{
+ context = "direct call";
+ check_alignments ();
+
+ atexit (check_alignments);
+
+ if (getcontext (&ucp) != 0)
+ FAIL_UNSUPPORTED ("getcontext");
+
+ ucp.uc_link = NULL;
+ ucp.uc_stack.ss_size = 512 * 1024;
+ ucp.uc_stack.ss_sp = xmmap (NULL, ucp.uc_stack.ss_size,
+ PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1);
+
+ support_isolate_in_subprocess (invoke_callback_0, NULL);
+ support_isolate_in_subprocess (invoke_callback_1, NULL);
+ support_isolate_in_subprocess (invoke_callback_2, NULL);
+ support_isolate_in_subprocess (invoke_callback_3, NULL);
+
+ return 0;
+}
+
+#include <support/test-driver.c>
diff --git a/sysdeps/unix/sysv/linux/i386/makecontext.S b/sysdeps/unix/sysv/linux/i386/makecontext.S
index efa4955033..e3ca3dc0d5 100644
--- a/sysdeps/unix/sysv/linux/i386/makecontext.S
+++ b/sysdeps/unix/sysv/linux/i386/makecontext.S
@@ -108,9 +108,19 @@ L(exitcode):
call HIDDEN_JUMPTARGET(__setcontext)
/* If this returns (which can happen if the syscall fails) we'll
exit the program with the return error value (-1). */
+ jmp L(call_exit)
- movl %eax, (%esp)
-2: call HIDDEN_JUMPTARGET(exit)
+2:
+ /* Exit with status 0. */
+ xorl %eax, %eax
+
+L(call_exit):
+ /* Align the stack and pass the exit code (from %eax). */
+ andl $0xfffffff0, %esp
+ subl $12, %esp
+ pushl %eax
+
+ call HIDDEN_JUMPTARGET(exit)
/* The 'exit' call should never return. In case it does cause
the process to terminate. */
hlt