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| author |   Christian Brauner <brauner@kernel.org> | 2024-10-08 13:30:49 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-10-22 11:16:58 +0200 |
| commit | 2714b0d1f36999dbd99a3474a24e7301acbd74f1 (patch) | |
| tree | b7d5fb2890cde3ece91a99a53d779bdd7f242370 | |
| parent | vfs: inode insertion kdoc corrections (diff) | |
| download | wireguard-linux-2714b0d1f36999dbd99a3474a24e7301acbd74f1.tar.xz wireguard-linux-2714b0d1f36999dbd99a3474a24e7301acbd74f1.zip | |
fcntl: make F_DUPFD_QUERY associative
Currently when passing a closed file descriptor to
fcntl(fd, F_DUPFD_QUERY, fd_dup) the order matters:
fd = open("/dev/null");
fd_dup = dup(fd);
When we now close one of the file descriptors we get:
(1) fcntl(fd, fd_dup) // -EBADF
(2) fcntl(fd_dup, fd) // 0 aka not equal
depending on which file descriptor is passed first. That's not a huge
deal but it gives the api I slightly weird feel. Make it so that the
order doesn't matter by requiring that both file descriptors are valid:
(1') fcntl(fd, fd_dup) // -EBADF
(2') fcntl(fd_dup, fd) // -EBADF
Link: https://lore.kernel.org/r/20241008-duften-formel-251f967602d5@brauner
Fixes: c62b758bae6a ("fcntl: add F_DUPFD_QUERY fcntl()")
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-By: Lennart Poettering <lennart@poettering.net>
Cc: stable@vger.kernel.org
Reported-by: Lennart Poettering <lennart@poettering.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
| -rw-r--r-- | fs/fcntl.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c index 22dd9dcce7ec..3d89de31066a 100644 --- a/fs/fcntl.c +++ b/fs/fcntl.c @@ -397,6 +397,9 @@ static long f_dupfd_query(int fd, struct file *filp) { CLASS(fd_raw, f)(fd); + if (fd_empty(f)) + return -EBADF; + /* * We can do the 'fdput()' immediately, as the only thing that * matters is the pointer value which isn't changed by the fdput. |