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Subject[03/39] cifs: NULL out tcon, pSesInfo, and srvTcp pointers when chasing DFS referrals
2.6.31-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Jeff Layton <jlayton@redhat.com>

commit a2934c7b363ddcc001964f2444649f909e583bef upstream.

The scenario is this:

The kernel gets EREMOTE and starts chasing a DFS referral at mount time.
The tcon reference is put, which puts the session reference too, but
neither pointer is zeroed out.

The mount gets retried (goto try_mount_again) with new mount info.
Session setup fails fails and rc ends up being non-zero. The code then
falls through to the end and tries to put the previously freed tcon
pointer again. Oops at: cifs_put_smb_ses+0x14/0xd0

Fix this by moving the initialization of the rc variable and the tcon,
pSesInfo and srvTcp pointers below the try_mount_again label. Also, add
a FreeXid() before the goto to prevent xid "leaks".

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reported-by: Gustavo Carvalho Homem <gustavo@angulosolido.pt>
Signed-off-by: Steve French <sfrench@us.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/cifs/connect.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2267,12 +2267,12 @@ int
cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
char *mount_data_global, const char *devname)
{
- int rc = 0;
+ int rc;
int xid;
struct smb_vol *volume_info;
- struct cifsSesInfo *pSesInfo = NULL;
- struct cifsTconInfo *tcon = NULL;
- struct TCP_Server_Info *srvTcp = NULL;
+ struct cifsSesInfo *pSesInfo;
+ struct cifsTconInfo *tcon;
+ struct TCP_Server_Info *srvTcp;
char *full_path;
char *mount_data = mount_data_global;
#ifdef CONFIG_CIFS_DFS_UPCALL
@@ -2281,6 +2281,10 @@ cifs_mount(struct super_block *sb, struc
int referral_walks_count = 0;
try_mount_again:
#endif
+ rc = 0;
+ tcon = NULL;
+ pSesInfo = NULL;
+ srvTcp = NULL;
full_path = NULL;

xid = GetXid();
@@ -2577,6 +2581,7 @@ remote_path_check:

cleanup_volume_info(&volume_info);
referral_walks_count++;
+ FreeXid(xid);
goto try_mount_again;
}
#else /* No DFS support, return error on mount */



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