cifs: Fix check for regular file in couldbe_mf_symlink()

spuiuk · smfrench · commit a9a315d41407 · 2014-01-31T09:06:43.000-06:00
MF Symlinks are regular files containing content in a specified format.

The function couldbe_mf_symlink() checks the mode for a set S_IFREG bit
as a test to confirm that it is a regular file. This bit is also set for
other filetypes and simply checking for this bit being set may return
false positives.

We ensure that we are actually checking for a regular file by using the
S_ISREG macro to test instead.

Signed-off-by: Sachin Prabhu &lt;sprabhu@redhat.com&gt;
Reviewed-by: Jeff Layton &lt;jlayton@redhat.com&gt;
Reported-by: Neil Brown &lt;neilb@suse.de&gt;
Reported-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Signed-off-by: Steve French &lt;smfrench@gmail.com&gt;
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
@@ -185,7 +185,7 @@ format_mf_symlink(u8 *buf, unsigned int buf_len, const char *link_str)
 bool
 couldbe_mf_symlink(const struct cifs_fattr *fattr)
 {
-	if (!(fattr->cf_mode & S_IFREG))
+	if (!S_ISREG(fattr->cf_mode))
 		/* it's not a symlink */
 		return false;
 

Original file line number	Diff line number	Diff line change
`@@ -185,7 +185,7 @@ format_mf_symlink(u8 buf, unsigned int buf_len, const char link_str)`
`185`	`185`	`bool`
`186`	`186`	`couldbe_mf_symlink(const struct cifs_fattr *fattr)`
`187`	`187`	`{`
`188`		`- if (!(fattr->cf_mode & S_IFREG))`
	`188`	`+ if (!S_ISREG(fattr->cf_mode))`
`189`	`189`	`/* it's not a symlink */`
`190`	`190`	`return false;`
`191`	`191`