| From f5bc1e755d23d022bf948904386337fc3e5e29a8 Mon Sep 17 00:00:00 2001 |
| From: Pavel Shilovsky <piastryyy@gmail.com> |
| Date: Mon, 25 Jul 2011 17:59:10 +0400 |
| Subject: CIFS: Fix oops while mounting with prefixpath |
| |
| From: Pavel Shilovsky <piastryyy@gmail.com> |
| |
| commit f5bc1e755d23d022bf948904386337fc3e5e29a8 upstream. |
| |
| commit fec11dd9a0109fe52fd631e5c510778d6cbff6cc caused |
| a regression when we have already mounted //server/share/a |
| and want to mount //server/share/a/b. |
| |
| The problem is that lookup_one_len calls __lookup_hash |
| with nd pointer as NULL. Then __lookup_hash calls |
| do_revalidate in the case when dentry exists and we end |
| up with NULL pointer deference in cifs_d_revalidate: |
| |
| if (nd->flags & LOOKUP_RCU) |
| return -ECHILD; |
| |
| Fix this by checking nd for NULL. |
| |
| Signed-off-by: Pavel Shilovsky <piastryyy@gmail.com> |
| Reviewed-by: Shirish Pargaonkar <shirishp@us.ibm.com> |
| Signed-off-by: Steve French <sfrench@us.ibm.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| |
| --- |
| fs/cifs/dir.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/fs/cifs/dir.c |
| +++ b/fs/cifs/dir.c |
| @@ -641,7 +641,7 @@ lookup_out: |
| static int |
| cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd) |
| { |
| - if (nd->flags & LOOKUP_RCU) |
| + if (nd && (nd->flags & LOOKUP_RCU)) |
| return -ECHILD; |
| |
| if (direntry->d_inode) { |
