* [PATCH 0/2] Fix S_ISDIR execve() errno
@ 2020-08-13 23:17 Kees Cook
2020-08-13 23:17 ` [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve() Kees Cook
2020-08-13 23:17 ` [PATCH 2/2] selftests/exec: Add file type errno tests Kees Cook
0 siblings, 2 replies; 6+ messages in thread
From: Kees Cook @ 2020-08-13 23:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Kees Cook, Marc Zyngier, Shuah Khan, Greg Kroah-Hartman,
linux-kernel, linux-kselftest
Hi Andrew,
This fixes an errno change for execve() of directories, noticed by Marc
Zyngier[1]. Along with the fix, include a regression test to avoid seeing
this return in the future.
Thanks!
-Kees
[1] https://lore.kernel.org/lkml/20200813151305.6191993b@why
Kees Cook (2):
exec: Restore EACCES of S_ISDIR execve()
selftests/exec: Add file type errno tests
fs/namei.c | 4 +-
tools/testing/selftests/exec/.gitignore | 1 +
tools/testing/selftests/exec/Makefile | 5 +-
tools/testing/selftests/exec/non-regular.c | 196 +++++++++++++++++++++
4 files changed, 203 insertions(+), 3 deletions(-)
create mode 100755 tools/testing/selftests/exec/non-regular.c
--
2.25.1
^ permalink raw reply [flat|nested] 6+ messages in thread
* [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve()
2020-08-13 23:17 [PATCH 0/2] Fix S_ISDIR execve() errno Kees Cook
@ 2020-08-13 23:17 ` Kees Cook
2020-08-14 7:11 ` Greg Kroah-Hartman
2020-08-14 8:15 ` Marc Zyngier
2020-08-13 23:17 ` [PATCH 2/2] selftests/exec: Add file type errno tests Kees Cook
1 sibling, 2 replies; 6+ messages in thread
From: Kees Cook @ 2020-08-13 23:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Kees Cook, Marc Zyngier, Shuah Khan, Greg Kroah-Hartman,
linux-kernel, linux-kselftest
The return code for attempting to execute a directory has always been
EACCES. Adjust the S_ISDIR exec test to reflect the old errno instead
of the general EISDIR for other kinds of "open" attempts on directories.
Reported-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
fs/namei.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/namei.c b/fs/namei.c
index 2112e578dccc..e99e2a9da0f7 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2849,8 +2849,10 @@ static int may_open(const struct path *path, int acc_mode, int flag)
case S_IFLNK:
return -ELOOP;
case S_IFDIR:
- if (acc_mode & (MAY_WRITE | MAY_EXEC))
+ if (acc_mode & MAY_WRITE)
return -EISDIR;
+ if (acc_mode & MAY_EXEC)
+ return -EACCES;
break;
case S_IFBLK:
case S_IFCHR:
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH 2/2] selftests/exec: Add file type errno tests
2020-08-13 23:17 [PATCH 0/2] Fix S_ISDIR execve() errno Kees Cook
2020-08-13 23:17 ` [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve() Kees Cook
@ 2020-08-13 23:17 ` Kees Cook
1 sibling, 0 replies; 6+ messages in thread
From: Kees Cook @ 2020-08-13 23:17 UTC (permalink / raw)
To: Andrew Morton
Cc: Kees Cook, Marc Zyngier, Shuah Khan, Greg Kroah-Hartman,
linux-kernel, linux-kselftest
Make sure execve() returns the expected errno values for non-regular
files.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
tools/testing/selftests/exec/.gitignore | 1 +
tools/testing/selftests/exec/Makefile | 5 +-
tools/testing/selftests/exec/non-regular.c | 196 +++++++++++++++++++++
3 files changed, 200 insertions(+), 2 deletions(-)
create mode 100755 tools/testing/selftests/exec/non-regular.c
diff --git a/tools/testing/selftests/exec/.gitignore b/tools/testing/selftests/exec/.gitignore
index 94b02a18f230..344a99c6da1b 100644
--- a/tools/testing/selftests/exec/.gitignore
+++ b/tools/testing/selftests/exec/.gitignore
@@ -10,3 +10,4 @@ execveat.denatured
/recursion-depth
xxxxxxxx*
pipe
+S_I*.test
diff --git a/tools/testing/selftests/exec/Makefile b/tools/testing/selftests/exec/Makefile
index 4453b8f8def3..0a13b110c1e6 100644
--- a/tools/testing/selftests/exec/Makefile
+++ b/tools/testing/selftests/exec/Makefile
@@ -3,7 +3,7 @@ CFLAGS = -Wall
CFLAGS += -Wno-nonnull
CFLAGS += -D_GNU_SOURCE
-TEST_PROGS := binfmt_script
+TEST_PROGS := binfmt_script non-regular
TEST_GEN_PROGS := execveat
TEST_GEN_FILES := execveat.symlink execveat.denatured script subdir pipe
# Makefile is a run-time dependency, since it's accessed by the execveat test
@@ -11,7 +11,8 @@ TEST_FILES := Makefile
TEST_GEN_PROGS += recursion-depth
-EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx*
+EXTRA_CLEAN := $(OUTPUT)/subdir.moved $(OUTPUT)/execveat.moved $(OUTPUT)/xxxxx* \
+ $(OUTPUT)/S_I*.test
include ../lib.mk
diff --git a/tools/testing/selftests/exec/non-regular.c b/tools/testing/selftests/exec/non-regular.c
new file mode 100755
index 000000000000..cd3a34aca93e
--- /dev/null
+++ b/tools/testing/selftests/exec/non-regular.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: GPL-2.0+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <sys/sysmacros.h>
+#include <sys/types.h>
+
+#include "../kselftest_harness.h"
+
+/* Remove a file, ignoring the result if it didn't exist. */
+void rm(struct __test_metadata *_metadata, const char *pathname,
+ int is_dir)
+{
+ int rc;
+
+ if (is_dir)
+ rc = rmdir(pathname);
+ else
+ rc = unlink(pathname);
+
+ if (rc < 0) {
+ ASSERT_EQ(errno, ENOENT) {
+ TH_LOG("Not ENOENT: %s", pathname);
+ }
+ } else {
+ ASSERT_EQ(rc, 0) {
+ TH_LOG("Failed to remove: %s", pathname);
+ }
+ }
+}
+
+FIXTURE(file) {
+ char *pathname;
+ int is_dir;
+};
+
+FIXTURE_VARIANT(file)
+{
+ const char *name;
+ int expected;
+ int is_dir;
+ void (*setup)(struct __test_metadata *_metadata,
+ FIXTURE_DATA(file) *self,
+ const FIXTURE_VARIANT(file) *variant);
+ int major, minor, mode; /* for mknod() */
+};
+
+void setup_link(struct __test_metadata *_metadata,
+ FIXTURE_DATA(file) *self,
+ const FIXTURE_VARIANT(file) *variant)
+{
+ const char * const paths[] = {
+ "/bin/true",
+ "/usr/bin/true",
+ };
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(paths); i++) {
+ if (access(paths[i], X_OK) == 0) {
+ ASSERT_EQ(symlink(paths[i], self->pathname), 0);
+ return;
+ }
+ }
+ ASSERT_EQ(1, 0) {
+ TH_LOG("Could not find viable 'true' binary");
+ }
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFLNK)
+{
+ .name = "S_IFLNK",
+ .expected = ELOOP,
+ .setup = setup_link,
+};
+
+void setup_dir(struct __test_metadata *_metadata,
+ FIXTURE_DATA(file) *self,
+ const FIXTURE_VARIANT(file) *variant)
+{
+ ASSERT_EQ(mkdir(self->pathname, 0755), 0);
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFDIR)
+{
+ .name = "S_IFDIR",
+ .is_dir = 1,
+ .expected = EACCES,
+ .setup = setup_dir,
+};
+
+void setup_node(struct __test_metadata *_metadata,
+ FIXTURE_DATA(file) *self,
+ const FIXTURE_VARIANT(file) *variant)
+{
+ dev_t dev;
+ int rc;
+
+ dev = makedev(variant->major, variant->minor);
+ rc = mknod(self->pathname, 0755 | variant->mode, dev);
+ ASSERT_EQ(rc, 0) {
+ if (errno == EPERM)
+ SKIP(return, "Please run as root; cannot mknod(%s)",
+ variant->name);
+ }
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFBLK)
+{
+ .name = "S_IFBLK",
+ .expected = EACCES,
+ .setup = setup_node,
+ /* /dev/loop0 */
+ .major = 7,
+ .minor = 0,
+ .mode = S_IFBLK,
+};
+
+FIXTURE_VARIANT_ADD(file, S_IFCHR)
+{
+ .name = "S_IFCHR",
+ .expected = EACCES,
+ .setup = setup_node,
+ /* /dev/zero */
+ .major = 1,
+ .minor = 5,
+ .mode = S_IFCHR,
+};
+
+void setup_fifo(struct __test_metadata *_metadata,
+ FIXTURE_DATA(file) *self,
+ const FIXTURE_VARIANT(file) *variant)
+{
+ ASSERT_EQ(mkfifo(self->pathname, 0755), 0);
+}
+
+FIXTURE_VARIANT_ADD(file, S_IFIFO)
+{
+ .name = "S_IFIFO",
+ .expected = EACCES,
+ .setup = setup_fifo,
+};
+
+FIXTURE_SETUP(file)
+{
+ ASSERT_GT(asprintf(&self->pathname, "%s.test", variant->name), 6);
+ self->is_dir = variant->is_dir;
+
+ rm(_metadata, self->pathname, variant->is_dir);
+ variant->setup(_metadata, self, variant);
+}
+
+FIXTURE_TEARDOWN(file)
+{
+ rm(_metadata, self->pathname, self->is_dir);
+}
+
+TEST_F(file, exec_errno)
+{
+ char * const argv[2] = { (char * const)self->pathname, NULL };
+
+ EXPECT_LT(execv(argv[0], argv), 0);
+ EXPECT_EQ(errno, variant->expected);
+}
+
+/* S_IFSOCK */
+FIXTURE(sock)
+{
+ int fd;
+};
+
+FIXTURE_SETUP(sock)
+{
+ self->fd = socket(AF_INET, SOCK_STREAM, 0);
+ ASSERT_GE(self->fd, 0);
+}
+
+FIXTURE_TEARDOWN(sock)
+{
+ if (self->fd >= 0)
+ ASSERT_EQ(close(self->fd), 0);
+}
+
+TEST_F(sock, exec_errno)
+{
+ char * const argv[2] = { " magic socket ", NULL };
+ char * const envp[1] = { NULL };
+
+ EXPECT_LT(fexecve(self->fd, argv, envp), 0);
+ EXPECT_EQ(errno, EACCES);
+}
+
+TEST_HARNESS_MAIN
--
2.25.1
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve()
2020-08-13 23:17 ` [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve() Kees Cook
@ 2020-08-14 7:11 ` Greg Kroah-Hartman
2020-08-14 8:13 ` Greg Kroah-Hartman
2020-08-14 8:15 ` Marc Zyngier
1 sibling, 1 reply; 6+ messages in thread
From: Greg Kroah-Hartman @ 2020-08-14 7:11 UTC (permalink / raw)
To: Kees Cook
Cc: Andrew Morton, Marc Zyngier, Shuah Khan, linux-kernel, linux-kselftest
On Thu, Aug 13, 2020 at 04:17:22PM -0700, Kees Cook wrote:
> The return code for attempting to execute a directory has always been
> EACCES. Adjust the S_ISDIR exec test to reflect the old errno instead
> of the general EISDIR for other kinds of "open" attempts on directories.
>
> Reported-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> fs/namei.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index 2112e578dccc..e99e2a9da0f7 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2849,8 +2849,10 @@ static int may_open(const struct path *path, int acc_mode, int flag)
> case S_IFLNK:
> return -ELOOP;
> case S_IFDIR:
> - if (acc_mode & (MAY_WRITE | MAY_EXEC))
> + if (acc_mode & MAY_WRITE)
> return -EISDIR;
> + if (acc_mode & MAY_EXEC)
> + return -EACCES;
> break;
> case S_IFBLK:
> case S_IFCHR:
Reviewed-by: Greg Kroah-Hartman <gregkh@google.com>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve()
2020-08-14 7:11 ` Greg Kroah-Hartman
@ 2020-08-14 8:13 ` Greg Kroah-Hartman
0 siblings, 0 replies; 6+ messages in thread
From: Greg Kroah-Hartman @ 2020-08-14 8:13 UTC (permalink / raw)
To: Kees Cook
Cc: Andrew Morton, Marc Zyngier, Shuah Khan, linux-kernel, linux-kselftest
On Fri, Aug 14, 2020 at 09:11:02AM +0200, Greg Kroah-Hartman wrote:
> On Thu, Aug 13, 2020 at 04:17:22PM -0700, Kees Cook wrote:
> > The return code for attempting to execute a directory has always been
> > EACCES. Adjust the S_ISDIR exec test to reflect the old errno instead
> > of the general EISDIR for other kinds of "open" attempts on directories.
> >
> > Reported-by: Marc Zyngier <maz@kernel.org>
> > Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> > Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > fs/namei.c | 4 +++-
> > 1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/namei.c b/fs/namei.c
> > index 2112e578dccc..e99e2a9da0f7 100644
> > --- a/fs/namei.c
> > +++ b/fs/namei.c
> > @@ -2849,8 +2849,10 @@ static int may_open(const struct path *path, int acc_mode, int flag)
> > case S_IFLNK:
> > return -ELOOP;
> > case S_IFDIR:
> > - if (acc_mode & (MAY_WRITE | MAY_EXEC))
> > + if (acc_mode & MAY_WRITE)
> > return -EISDIR;
> > + if (acc_mode & MAY_EXEC)
> > + return -EACCES;
> > break;
> > case S_IFBLK:
> > case S_IFCHR:
>
>
> Reviewed-by: Greg Kroah-Hartman <gregkh@google.com>
And to round out the "let's use a different email address for each
response, to drive accounting tools crazy!" effort, you can also add:
Tested-by: Greg Kroah-Hartman <gregkh@android.com>
thanks,
greg "I don't have enough different email addresses" k-h
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve()
2020-08-13 23:17 ` [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve() Kees Cook
2020-08-14 7:11 ` Greg Kroah-Hartman
@ 2020-08-14 8:15 ` Marc Zyngier
1 sibling, 0 replies; 6+ messages in thread
From: Marc Zyngier @ 2020-08-14 8:15 UTC (permalink / raw)
To: Kees Cook
Cc: Andrew Morton, Shuah Khan, Greg Kroah-Hartman, linux-kernel,
linux-kselftest
On 2020-08-14 00:17, Kees Cook wrote:
> The return code for attempting to execute a directory has always been
> EACCES. Adjust the S_ISDIR exec test to reflect the old errno instead
> of the general EISDIR for other kinds of "open" attempts on
> directories.
>
> Reported-by: Marc Zyngier <maz@kernel.org>
> Link: https://lore.kernel.org/lkml/20200813151305.6191993b@why
> Fixes: 633fb6ac3980 ("exec: move S_ISREG() check earlier")
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> fs/namei.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index 2112e578dccc..e99e2a9da0f7 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2849,8 +2849,10 @@ static int may_open(const struct path *path,
> int acc_mode, int flag)
> case S_IFLNK:
> return -ELOOP;
> case S_IFDIR:
> - if (acc_mode & (MAY_WRITE | MAY_EXEC))
> + if (acc_mode & MAY_WRITE)
> return -EISDIR;
> + if (acc_mode & MAY_EXEC)
> + return -EACCES;
> break;
> case S_IFBLK:
> case S_IFCHR:
Reviewed-by: Marc Zyngier <maz@kernel.org>
M.
--
Jazz is not dead. It just smells funny...
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2020-08-14 8:15 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-13 23:17 [PATCH 0/2] Fix S_ISDIR execve() errno Kees Cook
2020-08-13 23:17 ` [PATCH 1/2] exec: Restore EACCES of S_ISDIR execve() Kees Cook
2020-08-14 7:11 ` Greg Kroah-Hartman
2020-08-14 8:13 ` Greg Kroah-Hartman
2020-08-14 8:15 ` Marc Zyngier
2020-08-13 23:17 ` [PATCH 2/2] selftests/exec: Add file type errno tests Kees Cook
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