git: d0b7445904f5 - main - include: ssp: fortify <stdlib.h>
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Date: Sat, 13 Jul 2024 05:23:03 UTC
The branch main has been updated by kevans:
URL: https://cgit.FreeBSD.org/src/commit/?id=d0b7445904f592bf379d64932fb6f1fdc29c4aa7
commit d0b7445904f592bf379d64932fb6f1fdc29c4aa7
Author: Kyle Evans <kevans@FreeBSD.org>
AuthorDate: 2024-07-13 05:16:11 +0000
Commit: Kyle Evans <kevans@FreeBSD.org>
CommitDate: 2024-07-13 05:16:24 +0000
include: ssp: fortify <stdlib.h>
The immediately obvious and attractive targets from <stdlib.h> are
arc4random_buf(3) and realpath(3) -- scraping the header didn't reveal
much else of interest.
Reviewed by: markj
Sponsored by: Klara, Inc.
Sponsored by: Stormshield
Differential Revision: https://reviews.freebsd.org/D45681
---
include/ssp/Makefile | 2 +-
include/ssp/stdlib.h | 53 ++++
include/stdlib.h | 4 +
lib/libc/gen/arc4random.c | 3 +-
lib/libc/stdlib/realpath.c | 3 +-
lib/libc/tests/secure/Makefile | 1 +
lib/libc/tests/secure/fortify_stdlib_test.c | 383 +++++++++++++++++++++++
lib/libc/tests/secure/generate-fortify-tests.lua | 20 ++
8 files changed, 466 insertions(+), 3 deletions(-)
diff --git a/include/ssp/Makefile b/include/ssp/Makefile
index a97139e75c7b..2bbbc2eab705 100644
--- a/include/ssp/Makefile
+++ b/include/ssp/Makefile
@@ -1,4 +1,4 @@
-INCS= poll.h ssp.h stdio.h string.h strings.h unistd.h
+INCS= poll.h ssp.h stdio.h stdlib.h string.h strings.h unistd.h
INCSDIR= ${INCLUDEDIR}/ssp
.include <bsd.prog.mk>
diff --git a/include/ssp/stdlib.h b/include/ssp/stdlib.h
new file mode 100644
index 000000000000..f595ecbcbc0a
--- /dev/null
+++ b/include/ssp/stdlib.h
@@ -0,0 +1,53 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024, Klara, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#ifndef _SSP_STDLIB_H_
+#define _SSP_STDLIB_H_
+
+#include <ssp/ssp.h>
+
+#if __SSP_FORTIFY_LEVEL > 0
+
+#include <limits.h>
+
+__BEGIN_DECLS
+
+__ssp_redirect(void, arc4random_buf, (void *__buf, size_t __len),
+ (__buf, __len));
+
+__ssp_redirect_raw_impl(char *, realpath, realpath,
+ (const char *__restrict path, char *__restrict buf))
+{
+ if (__ssp_bos(buf) < PATH_MAX)
+ __chk_fail();
+
+ return (__ssp_real(realpath)(path, buf));
+}
+
+__END_DECLS
+
+#endif /* __SSP_FORTIFY_LEVEL > 0 */
+#endif /* _SSP_STDLIB_H_ */
diff --git a/include/stdlib.h b/include/stdlib.h
index db339688cb78..162031ab393d 100644
--- a/include/stdlib.h
+++ b/include/stdlib.h
@@ -69,6 +69,10 @@ typedef struct {
*/
#define RAND_MAX 0x7fffffff
+#if !defined(_STANDALONE) && defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0
+#include <ssp/stdlib.h>
+#endif
+
__BEGIN_DECLS
#ifdef _XLOCALE_H_
#include <xlocale/_stdlib.h>
diff --git a/lib/libc/gen/arc4random.c b/lib/libc/gen/arc4random.c
index fdb1688cfe9c..cc65e0131970 100644
--- a/lib/libc/gen/arc4random.c
+++ b/lib/libc/gen/arc4random.c
@@ -35,6 +35,7 @@
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
+#include <ssp/ssp.h>
#include <sys/types.h>
#include <sys/time.h>
@@ -243,7 +244,7 @@ arc4random(void)
}
void
-arc4random_buf(void *buf, size_t n)
+__ssp_real(arc4random_buf)(void *buf, size_t n)
{
_ARC4_LOCK();
_rs_random_buf(buf, n);
diff --git a/lib/libc/stdlib/realpath.c b/lib/libc/stdlib/realpath.c
index 992d14302fe0..554d70b43a29 100644
--- a/lib/libc/stdlib/realpath.c
+++ b/lib/libc/stdlib/realpath.c
@@ -37,6 +37,7 @@
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
+#include <ssp/ssp.h>
#include "un-namespace.h"
#include "libc_private.h"
@@ -203,7 +204,7 @@ realpath1(const char *path, char *resolved)
}
char *
-realpath(const char * __restrict path, char * __restrict resolved)
+__ssp_real(realpath)(const char * __restrict path, char * __restrict resolved)
{
char *m, *res;
diff --git a/lib/libc/tests/secure/Makefile b/lib/libc/tests/secure/Makefile
index 2e98b5f2ed35..63fe4cb96f02 100644
--- a/lib/libc/tests/secure/Makefile
+++ b/lib/libc/tests/secure/Makefile
@@ -3,6 +3,7 @@
TESTSDIR:= ${TESTSBASE}/${RELDIR:C/libc\/tests/libc/}
FORTIFY_TCATS+= poll
+FORTIFY_TCATS+= stdlib
FORTIFY_TCATS+= stdio
FORTIFY_TCATS+= string
FORTIFY_TCATS+= strings
diff --git a/lib/libc/tests/secure/fortify_stdlib_test.c b/lib/libc/tests/secure/fortify_stdlib_test.c
new file mode 100644
index 000000000000..e00983a58aa4
--- /dev/null
+++ b/lib/libc/tests/secure/fortify_stdlib_test.c
@@ -0,0 +1,383 @@
+/* @generated by `generate-fortify-tests.lua "stdlib"` */
+
+#define _FORTIFY_SOURCE 2
+#define TMPFILE_SIZE (1024 * 32)
+
+#include <sys/param.h>
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <sys/wait.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <poll.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <sysexits.h>
+#include <unistd.h>
+#include <atf-c.h>
+
+static FILE * __unused
+new_fp(size_t __len)
+{
+ static char fpbuf[LINE_MAX];
+ FILE *fp;
+
+ ATF_REQUIRE(__len <= sizeof(fpbuf));
+
+ memset(fpbuf, 'A', sizeof(fpbuf) - 1);
+ fpbuf[sizeof(fpbuf) - 1] = '\0';
+
+ fp = fmemopen(fpbuf, sizeof(fpbuf), "rb");
+ ATF_REQUIRE(fp != NULL);
+
+ return (fp);
+}
+
+/*
+ * Create a new symlink to use for readlink(2) style tests, we'll just use a
+ * random target name to have something interesting to look at.
+ */
+static const char * __unused
+new_symlink(size_t __len)
+{
+ static const char linkname[] = "link";
+ char target[MAXNAMLEN];
+ int error;
+
+ ATF_REQUIRE(__len <= sizeof(target));
+
+ arc4random_buf(target, sizeof(target));
+
+ error = unlink(linkname);
+ ATF_REQUIRE(error == 0 || errno == ENOENT);
+
+ error = symlink(target, linkname);
+ ATF_REQUIRE(error == 0);
+
+ return (linkname);
+}
+
+/*
+ * Constructs a tmpfile that we can use for testing read(2) and friends.
+ */
+static int __unused
+new_tmpfile(void)
+{
+ char buf[1024];
+ ssize_t rv;
+ size_t written;
+ int fd;
+
+ fd = open("tmpfile", O_RDWR | O_CREAT | O_TRUNC, 0644);
+ ATF_REQUIRE(fd >= 0);
+
+ written = 0;
+ while (written < TMPFILE_SIZE) {
+ rv = write(fd, buf, sizeof(buf));
+ ATF_REQUIRE(rv > 0);
+
+ written += rv;
+ }
+
+ ATF_REQUIRE_EQ(0, lseek(fd, 0, SEEK_SET));
+ return (fd);
+}
+
+static void
+disable_coredumps(void)
+{
+ struct rlimit rl = { 0 };
+
+ if (setrlimit(RLIMIT_CORE, &rl) == -1)
+ _exit(EX_OSERR);
+}
+
+/*
+ * Replaces stdin with a file that we can actually read from, for tests where
+ * we want a FILE * or fd that we can get data from.
+ */
+static void __unused
+replace_stdin(void)
+{
+ int fd;
+
+ fd = new_tmpfile();
+
+ (void)dup2(fd, STDIN_FILENO);
+ if (fd != STDIN_FILENO)
+ close(fd);
+}
+
+ATF_TC_WITHOUT_HEAD(arc4random_buf_before_end);
+ATF_TC_BODY(arc4random_buf_before_end, tc)
+{
+#define BUF &__stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char __buf[42];
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(__stack.__buf);
+ const size_t __len = 42 - 1;
+ const size_t __idx __unused = __len - 1;
+
+ arc4random_buf(__stack.__buf, __len);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(arc4random_buf_end);
+ATF_TC_BODY(arc4random_buf_end, tc)
+{
+#define BUF &__stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char __buf[42];
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(__stack.__buf);
+ const size_t __len = 42;
+ const size_t __idx __unused = __len - 1;
+
+ arc4random_buf(__stack.__buf, __len);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(arc4random_buf_heap_before_end);
+ATF_TC_BODY(arc4random_buf_heap_before_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (42);
+ const size_t __len = 42 - 1;
+ const size_t __idx __unused = __len - 1;
+
+ __stack.__buf = malloc(__bufsz);
+
+ arc4random_buf(__stack.__buf, __len);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(arc4random_buf_heap_end);
+ATF_TC_BODY(arc4random_buf_heap_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (42);
+ const size_t __len = 42;
+ const size_t __idx __unused = __len - 1;
+
+ __stack.__buf = malloc(__bufsz);
+
+ arc4random_buf(__stack.__buf, __len);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(arc4random_buf_heap_after_end);
+ATF_TC_BODY(arc4random_buf_heap_after_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (42);
+ const size_t __len = 42 + 1;
+ const size_t __idx __unused = __len - 1;
+ pid_t __child;
+ int __status;
+
+ __child = fork();
+ ATF_REQUIRE(__child >= 0);
+ if (__child > 0)
+ goto monitor;
+
+ /* Child */
+ disable_coredumps();
+ __stack.__buf = malloc(__bufsz);
+
+ arc4random_buf(__stack.__buf, __len);
+ _exit(EX_SOFTWARE); /* Should have aborted. */
+
+monitor:
+ while (waitpid(__child, &__status, 0) != __child) {
+ ATF_REQUIRE_EQ(EINTR, errno);
+ }
+
+ if (!WIFSIGNALED(__status)) {
+ switch (WEXITSTATUS(__status)) {
+ case EX_SOFTWARE:
+ atf_tc_fail("FORTIFY_SOURCE failed to abort");
+ break;
+ case EX_OSERR:
+ atf_tc_fail("setrlimit(2) failed");
+ break;
+ default:
+ atf_tc_fail("child exited with status %d",
+ WEXITSTATUS(__status));
+ }
+ } else {
+ ATF_REQUIRE_EQ(SIGABRT, WTERMSIG(__status));
+ }
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(realpath_before_end);
+ATF_TC_BODY(realpath_before_end, tc)
+{
+#define BUF &__stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char __buf[PATH_MAX + 1];
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(__stack.__buf);
+ const size_t __len = PATH_MAX + 1;
+ const size_t __idx __unused = __len - 1;
+
+ realpath(".", __stack.__buf);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(realpath_end);
+ATF_TC_BODY(realpath_end, tc)
+{
+#define BUF &__stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char __buf[PATH_MAX];
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(__stack.__buf);
+ const size_t __len = PATH_MAX;
+ const size_t __idx __unused = __len - 1;
+
+ realpath(".", __stack.__buf);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(realpath_heap_before_end);
+ATF_TC_BODY(realpath_heap_before_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (PATH_MAX + 1);
+ const size_t __len = PATH_MAX + 1;
+ const size_t __idx __unused = __len - 1;
+
+ __stack.__buf = malloc(__bufsz);
+
+ realpath(".", __stack.__buf);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(realpath_heap_end);
+ATF_TC_BODY(realpath_heap_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (PATH_MAX);
+ const size_t __len = PATH_MAX;
+ const size_t __idx __unused = __len - 1;
+
+ __stack.__buf = malloc(__bufsz);
+
+ realpath(".", __stack.__buf);
+#undef BUF
+
+}
+
+ATF_TC_WITHOUT_HEAD(realpath_heap_after_end);
+ATF_TC_BODY(realpath_heap_after_end, tc)
+{
+#define BUF __stack.__buf
+ struct {
+ uint8_t padding_l;
+ unsigned char * __buf;
+ uint8_t padding_r;
+ } __stack;
+ const size_t __bufsz __unused = sizeof(*__stack.__buf) * (PATH_MAX - 1);
+ const size_t __len = PATH_MAX - 1;
+ const size_t __idx __unused = __len - 1;
+ pid_t __child;
+ int __status;
+
+ __child = fork();
+ ATF_REQUIRE(__child >= 0);
+ if (__child > 0)
+ goto monitor;
+
+ /* Child */
+ disable_coredumps();
+ __stack.__buf = malloc(__bufsz);
+
+ realpath(".", __stack.__buf);
+ _exit(EX_SOFTWARE); /* Should have aborted. */
+
+monitor:
+ while (waitpid(__child, &__status, 0) != __child) {
+ ATF_REQUIRE_EQ(EINTR, errno);
+ }
+
+ if (!WIFSIGNALED(__status)) {
+ switch (WEXITSTATUS(__status)) {
+ case EX_SOFTWARE:
+ atf_tc_fail("FORTIFY_SOURCE failed to abort");
+ break;
+ case EX_OSERR:
+ atf_tc_fail("setrlimit(2) failed");
+ break;
+ default:
+ atf_tc_fail("child exited with status %d",
+ WEXITSTATUS(__status));
+ }
+ } else {
+ ATF_REQUIRE_EQ(SIGABRT, WTERMSIG(__status));
+ }
+#undef BUF
+
+}
+
+ATF_TP_ADD_TCS(tp)
+{
+ ATF_TP_ADD_TC(tp, arc4random_buf_before_end);
+ ATF_TP_ADD_TC(tp, arc4random_buf_end);
+ ATF_TP_ADD_TC(tp, arc4random_buf_heap_before_end);
+ ATF_TP_ADD_TC(tp, arc4random_buf_heap_end);
+ ATF_TP_ADD_TC(tp, arc4random_buf_heap_after_end);
+ ATF_TP_ADD_TC(tp, realpath_before_end);
+ ATF_TP_ADD_TC(tp, realpath_end);
+ ATF_TP_ADD_TC(tp, realpath_heap_before_end);
+ ATF_TP_ADD_TC(tp, realpath_heap_end);
+ ATF_TP_ADD_TC(tp, realpath_heap_after_end);
+ return (atf_no_error());
+}
diff --git a/lib/libc/tests/secure/generate-fortify-tests.lua b/lib/libc/tests/secure/generate-fortify-tests.lua
index bb654bbf2f71..b559fbded070 100755
--- a/lib/libc/tests/secure/generate-fortify-tests.lua
+++ b/lib/libc/tests/secure/generate-fortify-tests.lua
@@ -262,6 +262,26 @@ local all_tests = {
]],
},
},
+ stdlib = {
+ -- <stdlib.h>
+ {
+ func = "arc4random_buf",
+ arguments = {
+ "__buf",
+ "__len",
+ },
+ exclude = excludes_stack_overflow,
+ },
+ {
+ func = "realpath",
+ bufsize = "PATH_MAX",
+ arguments = {
+ "\".\"",
+ "__buf",
+ },
+ exclude = excludes_stack_overflow,
+ },
+ },
string = {
-- <string.h>
{