[v2] linux: Make fdopendir fail with O_PATH (BZ 30373)
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| redhat-pt-bot/TryBot-apply_patch |
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Patch applied to master at the time it was sent
|
| linaro-tcwg-bot/tcwg_glibc_check--master-aarch64 |
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|
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| redhat-pt-bot/TryBot-32bit |
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Build for i686
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| linaro-tcwg-bot/tcwg_glibc_build--master-arm |
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| linaro-tcwg-bot/tcwg_glibc_check--master-arm |
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| linaro-tcwg-bot/tcwg_glibc_build--master-aarch64 |
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Commit Message
It is not strictly required by the POSIX, since O_PATH is a Linux
extension, but it is QoI to fail early instead of at readdir. Also
the check is free, since fdopendir already checks if the file
descriptor is opened for read.
Checked on x86_64-linux-gnu.
---
sysdeps/unix/sysv/linux/Makefile | 1 +
sysdeps/unix/sysv/linux/fdopendir.c | 8 +++-
.../unix/sysv/linux/tst-fdopendir-o_path.c | 48 +++++++++++++++++++
3 files changed, 56 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/unix/sysv/linux/tst-fdopendir-o_path.c
Comments
On 2023-09-01 05:26, Adhemerval Zanella wrote:
> + /* Fail early for descriptors opened with O_PATH. */
> + if (__glibc_unlikely (flags & O_PATH))
> + {
> + __set_errno (EBADF);
> + return NULL;
> + }
> + /* Make sure the descriptor allows for reading. */
> if (__glibc_unlikely ((flags & O_ACCMODE) == O_WRONLY))
> {
> __set_errno (EINVAL);
Why use EBADF for one situation but EINVAL in the other?
POSIX says it should be EBADF for both situations. Arguably this is a
separate bug, but we should fix both bugs (and fix the documentation
too, to match POSIX).
On 01/09/23 14:57, Paul Eggert wrote:
> On 2023-09-01 05:26, Adhemerval Zanella wrote:
>> + /* Fail early for descriptors opened with O_PATH. */
>> + if (__glibc_unlikely (flags & O_PATH))
>> + {
>> + __set_errno (EBADF);
>> + return NULL;
>> + }
>> + /* Make sure the descriptor allows for reading. */
>> if (__glibc_unlikely ((flags & O_ACCMODE) == O_WRONLY))
>> {
>> __set_errno (EINVAL);
>
> Why use EBADF for one situation but EINVAL in the other?
>
> POSIX says it should be EBADF for both situations. Arguably this is a separate bug, but we should fix both bugs (and fix the documentation too, to match POSIX).
Right, but I think it should a different patch. I can send the fix
once this get installed.
@@ -199,6 +199,7 @@ tests += \
tst-clone3 \
tst-epoll \
tst-fanotify \
+ tst-fdopendir-o_path \
tst-getauxval \
tst-gettid \
tst-gettid-kill \
@@ -37,10 +37,16 @@ __fdopendir (int fd)
return NULL;
}
- /* Make sure the descriptor allows for reading. */
int flags = __fcntl64_nocancel (fd, F_GETFL);
if (__glibc_unlikely (flags == -1))
return NULL;
+ /* Fail early for descriptors opened with O_PATH. */
+ if (__glibc_unlikely (flags & O_PATH))
+ {
+ __set_errno (EBADF);
+ return NULL;
+ }
+ /* Make sure the descriptor allows for reading. */
if (__glibc_unlikely ((flags & O_ACCMODE) == O_WRONLY))
{
__set_errno (EINVAL);
new file mode 100644
@@ -0,0 +1,48 @@
+/* Check if fdopendir fails with file descriptor opened with O_PATH (BZ 30737)
+ Copyright (C) 2023 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
+ <https://www.gnu.org/licenses/>. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <dirent.h>
+#include <support/check.h>
+#include <support/temp_file.h>
+#include <support/xunistd.h>
+
+static int
+do_test (void)
+{
+ char *dirname = support_create_temp_directory ("tst-fdopendir-o_path");
+
+ {
+ int fd = xopen (dirname, O_RDONLY | O_DIRECTORY, 0600);
+ DIR *dir = fdopendir (fd);
+ TEST_VERIFY_EXIT (dir != NULL);
+ closedir (dir);
+ }
+
+ {
+ int fd = xopen (dirname, O_RDONLY | O_PATH | O_DIRECTORY, 0600);
+ TEST_VERIFY (fdopendir (fd) == NULL);
+ TEST_COMPARE (errno, EBADF);
+ xclose (fd);
+ }
+
+ return 0;
+}
+
+#include <support/test-driver.c>