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authorEric Biggers <ebiggers3@gmail.com>2014-03-16 15:47:48 -0500
committerAl Viro <viro@zeniv.linux.org.uk>2014-03-23 00:03:12 -0400
commit99aea68134f3c2a27b4d463c91cfa298c3efaccf (patch)
tree6b57fe890caaa2ff026a9d54a42f9ac95b96fee9
parentd7a15f8d0777955986a2ab00ab181795cab14b01 (diff)
vfs: Don't let __fdget_pos() get FMODE_PATH files
Commit bd2a31d522344 ("get rid of fget_light()") introduced the __fdget_pos() function, which returns the resulting file pointer and fdput flags combined in an 'unsigned long'. However, it also changed the behavior to return files with FMODE_PATH set, which shouldn't happen because read(), write(), lseek(), etc. aren't allowed on such files. This commit restores the old behavior. This regression actually had no effect on read() and write() since FMODE_READ and FMODE_WRITE are not set on file descriptors opened with O_PATH, but it did cause lseek() on a file descriptor opened with O_PATH to fail with ESPIPE rather than EBADF. Signed-off-by: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
-rw-r--r--fs/file.c19
1 files changed, 4 insertions, 15 deletions
diff --git a/fs/file.c b/fs/file.c
index 60a45e9f5323..eb56a13dab3e 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -713,27 +713,16 @@ unsigned long __fdget_raw(unsigned int fd)
unsigned long __fdget_pos(unsigned int fd)
{
- struct files_struct *files = current->files;
- struct file *file;
- unsigned long v;
-
- if (atomic_read(&files->count) == 1) {
- file = __fcheck_files(files, fd);
- v = 0;
- } else {
- file = __fget(fd, 0);
- v = FDPUT_FPUT;
- }
- if (!file)
- return 0;
+ unsigned long v = __fdget(fd);
+ struct file *file = (struct file *)(v & ~3);
- if (file->f_mode & FMODE_ATOMIC_POS) {
+ if (file && (file->f_mode & FMODE_ATOMIC_POS)) {
if (file_count(file) > 1) {
v |= FDPUT_POS_UNLOCK;
mutex_lock(&file->f_pos_lock);
}
}
- return v | (unsigned long)file;
+ return v;
}
/*