Attachment 2563 Details for Bug 2142 – libseccomp patch v2

[patch] libseccomp patch v2

openssh-6.7p1-x32-seccomp.patch (text/plain), 7.69 KB, created by Steven Noonan on 2015-03-07 01:26:29 AEDT

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Creator: Steven Noonan

Created: 2015-03-07 01:26:29 AEDT

Size: 7.69 KB

patch

obsolete

>diff --git a/Makefile.in b/Makefile.in
>index 06be3d5..b1f0931 100644
>--- a/Makefile.in
>+++ b/Makefile.in
>@@ -106,7 +106,7 @@ SSHDOBJS=sshd.o auth-rhosts.o auth-passwd.o auth-rsa.o auth-rh-rsa.o \
> 	sftp-server.o sftp-common.o \
> 	roaming_common.o roaming_serv.o \
> 	sandbox-null.o sandbox-rlimit.o sandbox-systrace.o sandbox-darwin.o \
>-	sandbox-seccomp-filter.o sandbox-capsicum.o
>+	sandbox-seccomp-filter.o sandbox-libseccomp-filter.o sandbox-capsicum.o
> 
> MANPAGES	= moduli.5.out scp.1.out ssh-add.1.out ssh-agent.1.out ssh-keygen.1.out ssh-keyscan.1.out ssh.1.out sshd.8.out sftp-server.8.out sftp.1.out ssh-keysign.8.out ssh-pkcs11-helper.8.out sshd_config.5.out ssh_config.5.out
> MANPAGES_IN	= moduli.5 scp.1 ssh-add.1 ssh-agent.1 ssh-keygen.1 ssh-keyscan.1 ssh.1 sshd.8 sftp-server.8 sftp.1 ssh-keysign.8 ssh-pkcs11-helper.8 sshd_config.5 ssh_config.5
>diff --git a/configure.ac b/configure.ac
>index 67c4486..ddaf7c0 100644
>--- a/configure.ac
>+++ b/configure.ac
>@@ -2867,11 +2867,22 @@ else
> fi
> AC_SUBST([SSH_PRIVSEP_USER])
> 
>+AC_CHECK_DECL([SCMP_ARCH_NATIVE], [have_libseccomp_filter=1], , [
>+	#include <sys/types.h>
>+	#include <seccomp.h>
>+])
>+if test "x$have_libseccomp_filter" = "x1" ; then
>+	AC_CHECK_LIB([seccomp], [seccomp_init],
>+				 [LIBS="$LIBS -lseccomp"],
>+				 [have_libseccomp_filter=0])
>+fi
>+
> if test "x$have_linux_no_new_privs" = "x1" ; then
> AC_CHECK_DECL([SECCOMP_MODE_FILTER], [have_seccomp_filter=1], , [
> 	#include <sys/types.h>
> 	#include <linux/seccomp.h>
> ])
>+
> fi
> if test "x$have_seccomp_filter" = "x1" ; then
> AC_MSG_CHECKING([kernel for seccomp_filter support])
>@@ -2898,7 +2909,7 @@ fi
> # Decide which sandbox style to use
> sandbox_arg=""
> AC_ARG_WITH([sandbox],
>-	[  --with-sandbox=style    Specify privilege separation sandbox (no, darwin, rlimit, systrace, seccomp_filter, capsicum)],
>+	[  --with-sandbox=style    Specify privilege separation sandbox (no, darwin, rlimit, systrace, seccomp_filter, libseccomp_filter, capsicum)],
> 	[
> 		if test "x$withval" = "xyes" ; then
> 			sandbox_arg=""
>@@ -3008,6 +3019,13 @@ elif test "x$sandbox_arg" = "xdarwin" || \
> 		AC_MSG_ERROR([Darwin seatbelt sandbox requires sandbox.h and sandbox_init function])
> 	SANDBOX_STYLE="darwin"
> 	AC_DEFINE([SANDBOX_DARWIN], [1], [Sandbox using Darwin sandbox_init(3)])
>+elif test "x$sandbox_arg" = "xlibseccomp_filter" || \
>+     ( test -z "$sandbox_arg" && \
>+       test "x$have_libseccomp_filter" = "x1" ) ; then
>+	test "x$have_libseccomp_filter" != "x1" && \
>+		AC_MSG_ERROR([libseccomp_filter sandbox not supported on $host])
>+        SANDBOX_STYLE="libseccomp_filter"
>+        AC_DEFINE([SANDBOX_LIBSECCOMP_FILTER], [1], [Sandbox using libseccomp filter])
> elif test "x$sandbox_arg" = "xseccomp_filter" || \
>      ( test -z "$sandbox_arg" && \
>        test "x$have_seccomp_filter" = "x1" && \
>diff --git a/sandbox-libseccomp-filter.c b/sandbox-libseccomp-filter.c
>new file mode 100644
>index 0000000..d03856b
>--- /dev/null
>+++ b/sandbox-libseccomp-filter.c
>@@ -0,0 +1,175 @@
>+/*
>+ * Copyright (c) 2012 Will Drewry <wad@dataspill.org>
>+ *
>+ * Permission to use, copy, modify, and distribute this software for any
>+ * purpose with or without fee is hereby granted, provided that the above
>+ * copyright notice and this permission notice appear in all copies.
>+ *
>+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
>+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
>+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
>+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
>+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
>+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
>+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
>+ */
>+
>+#include "includes.h"
>+
>+#ifdef SANDBOX_LIBSECCOMP_FILTER
>+
>+#include <sys/types.h>
>+#include <sys/resource.h>
>+#include <seccomp.h>
>+
>+#include <errno.h>
>+#include <signal.h>
>+#include <stdarg.h>
>+#include <stddef.h>  /* for offsetof */
>+#include <stdio.h>
>+#include <stdlib.h>
>+#include <string.h>
>+#include <unistd.h>
>+
>+#include "log.h"
>+#include "ssh-sandbox.h"
>+#include "xmalloc.h"
>+
>+struct ssh_sandbox {
>+	pid_t child_pid;
>+};
>+
>+struct ssh_sandbox *
>+ssh_sandbox_init(struct monitor *monitor)
>+{
>+	struct ssh_sandbox *box;
>+
>+	/*
>+	 * Strictly, we don't need to maintain any state here but we need
>+	 * to return non-NULL to satisfy the API.
>+	 */
>+	debug3("%s: preparing libseccomp filter sandbox", __func__);
>+	box = xcalloc(1, sizeof(*box));
>+	box->child_pid = 0;
>+
>+	return box;
>+}
>+
>+static int
>+seccomp_add_secondary_archs(scmp_filter_ctx *c)
>+{
>+#if defined(__i386__) || defined(__x86_64__)
>+	int r;
>+	r = seccomp_arch_add(c, SCMP_ARCH_X86);
>+	if (r < 0 && r != -EEXIST)
>+		return r;
>+	r = seccomp_arch_add(c, SCMP_ARCH_X86_64);
>+	if (r < 0 && r != -EEXIST)
>+		return r;
>+	r = seccomp_arch_add(c, SCMP_ARCH_X32);
>+	if (r < 0 && r != -EEXIST)
>+		return r;
>+#endif
>+	return 0;
>+}
>+
>+struct scmp_action_def {
>+	uint32_t action;
>+	int syscall;
>+};
>+
>+static const struct scmp_action_def preauth_insns[] = {
>+	{SCMP_ACT_ERRNO(EACCES), SCMP_SYS(open)},
>+	{SCMP_ACT_ERRNO(EACCES), SCMP_SYS(stat)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(getpid)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(getpid)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(gettimeofday)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(clock_gettime)},
>+#ifdef __NR_time /* not defined on EABI ARM */
>+	{SCMP_ACT_ALLOW, SCMP_SYS(time)},
>+#endif
>+	{SCMP_ACT_ALLOW, SCMP_SYS(read)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(write)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(close)},
>+#ifdef __NR_shutdown /* not defined on archs that go via socketcall(2) */
>+	{SCMP_ACT_ALLOW, SCMP_SYS(shutdown)},
>+#endif
>+	{SCMP_ACT_ALLOW, SCMP_SYS(brk)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(poll)},
>+#ifdef __NR__newselect
>+	{SCMP_ACT_ALLOW, SCMP_SYS(_newselect)},
>+#endif
>+	{SCMP_ACT_ALLOW, SCMP_SYS(select)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(madvise)},
>+#ifdef __NR_mmap2 /* EABI ARM only has mmap2() */
>+	{SCMP_ACT_ALLOW, SCMP_SYS(mmap2)},
>+#endif
>+#ifdef __NR_mmap
>+	{SCMP_ACT_ALLOW, SCMP_SYS(mmap)},
>+#endif
>+#ifdef __dietlibc__
>+	{SCMP_ACT_ALLOW, SCMP_SYS(mremap)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(exit)},
>+#endif
>+	{SCMP_ACT_ALLOW, SCMP_SYS(munmap)},
>+	{SCMP_ACT_ALLOW, SCMP_SYS(exit_group)},
>+#ifdef __NR_rt_sigprocmask
>+	{SCMP_ACT_ALLOW, SCMP_SYS(rt_sigprocmask)},
>+#else
>+	{SCMP_ACT_ALLOW, SCMP_SYS(sigprocmask)},
>+#endif
>+	{0, 0}
>+};
>+
>+
>+void
>+ssh_sandbox_child(struct ssh_sandbox *box)
>+{
>+	scmp_filter_ctx *seccomp;
>+	struct rlimit rl_zero;
>+	const struct scmp_action_def *insn;
>+	int r;
>+
>+	/* Set rlimits for completeness if possible. */
>+	rl_zero.rlim_cur = rl_zero.rlim_max = 0;
>+	if (setrlimit(RLIMIT_FSIZE, &rl_zero) == -1)
>+		fatal("%s: setrlimit(RLIMIT_FSIZE, { 0, 0 }): %s",
>+			__func__, strerror(errno));
>+	if (setrlimit(RLIMIT_NOFILE, &rl_zero) == -1)
>+		fatal("%s: setrlimit(RLIMIT_NOFILE, { 0, 0 }): %s",
>+			__func__, strerror(errno));
>+	if (setrlimit(RLIMIT_NPROC, &rl_zero) == -1)
>+		fatal("%s: setrlimit(RLIMIT_NPROC, { 0, 0 }): %s",
>+			__func__, strerror(errno));
>+
>+	seccomp = seccomp_init(SCMP_ACT_KILL);
>+	if (!seccomp)
>+		fatal("%s:libseccomp activation failed", __func__);
>+	if (seccomp_add_secondary_archs(seccomp))
>+		fatal("%s:libseccomp secondary arch setup failed", __func__);
>+
>+	for (insn = preauth_insns; insn->action; insn++) {
>+		if (seccomp_rule_add(seccomp, insn->action, insn->syscall, 0) < 0)
>+			fatal("%s:libseccomp rule failed", __func__);
>+	}
>+
>+	if ((r = seccomp_load(seccomp)) < 0)
>+		fatal("%s:libseccomp unable to load filter %d", __func__, r);
>+
>+	seccomp_release(seccomp);
>+}
>+
>+void
>+ssh_sandbox_parent_finish(struct ssh_sandbox *box)
>+{
>+	free(box);
>+	debug3("%s: finished", __func__);
>+}
>+
>+void
>+ssh_sandbox_parent_preauth(struct ssh_sandbox *box, pid_t child_pid)
>+{
>+	box->child_pid = child_pid;
>+}
>+
>+#endif /* SANDBOX_LIBSECCOMP_FILTER */

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