From: Yaakov Selkowitz <yselkowi@redhat.com>
To: newlib@sourceware.org
Subject: [PATCH v5 01/10] ssp: add APIs for Stack Smashing Protection
Date: Wed, 29 Nov 2017 09:43:00 -0000 [thread overview]
Message-ID: <20171129094300.20296-2-yselkowi@redhat.com> (raw)
In-Reply-To: <20171129094300.20296-1-yselkowi@redhat.com>
Compiling with any of the -fstack-protector* flags requires the
__stack_chk_guard data import (which needs to be initialized) and the
__stack_chk_fail{,_local} functions. While GCC's own libssp can provide
these, it is better that we provide these ourselves. The implementation
is custom due to being OS-specific.
Signed-off-by: Yaakov Selkowitz <yselkowi@redhat.com>
---
newlib/libc/ssp/stack_protector.c | 45 +++++++++++++++++++++++++++++++++++++++
1 file changed, 45 insertions(+)
create mode 100644 newlib/libc/ssp/stack_protector.c
diff --git a/newlib/libc/ssp/stack_protector.c b/newlib/libc/ssp/stack_protector.c
new file mode 100644
index 000000000..ee014b69d
--- /dev/null
+++ b/newlib/libc/ssp/stack_protector.c
@@ -0,0 +1,45 @@
+#include <sys/cdefs.h>
+#include <sys/param.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+uintptr_t __stack_chk_guard = 0;
+
+void
+__attribute__((__constructor__))
+__stack_chk_init (void)
+{
+ if (__stack_chk_guard != 0)
+ return;
+
+#if defined(__CYGWIN__) || defined(__rtems__)
+ arc4random_buf(&__stack_chk_guard, sizeof(__stack_chk_guard));
+#else
+ /* If getentropy is not available, use the "terminator canary". */
+ ((unsigned char *)&__stack_chk_guard)[0] = 0;
+ ((unsigned char *)&__stack_chk_guard)[1] = 0;
+ ((unsigned char *)&__stack_chk_guard)[2] = '\n';
+ ((unsigned char *)&__stack_chk_guard)[3] = 255;
+#endif
+}
+
+void
+__attribute__((__noreturn__))
+__stack_chk_fail (void)
+{
+ char msg[] = "*** stack smashing detected ***: terminated\n";
+ write (2, msg, strlen (msg));
+ raise (SIGABRT);
+ _exit (127);
+}
+
+#ifdef __ELF__
+void
+__attribute__((visibility ("hidden")))
+__stack_chk_fail_local (void)
+{
+ __stack_chk_fail();
+}
+#endif
--
2.15.0
next prev parent reply other threads:[~2017-11-29 9:43 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-29 9:49 [PATCH v5 00/10] Add Stack Smashing Protection and Object Size Checking Yaakov Selkowitz
2017-11-29 9:43 ` Yaakov Selkowitz [this message]
2017-11-29 9:43 ` [PATCH v5 02/10] ssp: add Object Size Checking common code Yaakov Selkowitz
2017-11-29 9:43 ` [PATCH v5 07/10] ssp: add documentation Yaakov Selkowitz
2017-11-29 9:43 ` [PATCH v5 05/10] ssp: add Object Size Checking for stdio.h, part 1 Yaakov Selkowitz
2017-11-29 9:43 ` [PATCH v5 03/10] ssp: add Object Size Checking for string.h Yaakov Selkowitz
2017-11-29 9:51 ` [PATCH v5 09/10] cygwin: export SSP functions Yaakov Selkowitz
2017-11-29 9:51 ` [PATCH v5 10/10] cygwin: create libssp compatibility import library Yaakov Selkowitz
2017-11-29 9:51 ` [PATCH v5 06/10] ssp: add Object Size Checking for unistd.h, part 1 Yaakov Selkowitz
2017-11-29 9:53 ` [PATCH v5 08/10] ssp: add build infrastructure Yaakov Selkowitz
2017-11-29 17:22 ` [PATCH v5 04/10] ssp: add Object Size Checking for strings.h Yaakov Selkowitz
2017-11-30 1:43 ` [PATCH v5 00/10] Add Stack Smashing Protection and Object Size Checking Corinna Vinschen
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