[PATCH AUTOSEL 4.19 225/252] cifs: fix NULL dereference in match_prepath

[PATCH AUTOSEL 4.19 225/252] cifs: fix NULL dereference in match_prepath

[Sasha Levin]

From: Ronnie Sahlberg <lsahlber@redhat.com>

[ Upstream commit fe1292686333d1dadaf84091f585ee903b9ddb84 ]

RHBZ: 1760879

Fix an oops in match_prepath() by making sure that the prepath string is not
NULL before we pass it into strcmp().

This is similar to other checks we make for example in cifs_root_iget()

Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/connect.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 576cf71576da1..6c62ce40608a1 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -3342,8 +3342,10 @@ match_prepath(struct super_block *sb, struct cifs_mnt_data *mnt_data)
 {
 	struct cifs_sb_info *old = CIFS_SB(sb);
 	struct cifs_sb_info *new = mnt_data->cifs_sb;
-	bool old_set = old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
-	bool new_set = new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH;
+	bool old_set = (old->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		old->prepath;
+	bool new_set = (new->mnt_cifs_flags & CIFS_MOUNT_USE_PREFIX_PATH) &&
+		new->prepath;
 
 	if (old_set && new_set && !strcmp(new->prepath, old->prepath))
 		return 1;
-- 
2.20.1

[PATCH AUTOSEL 4.19 250/252] cifs: log warning message (once) if out of disk space

[Sasha Levin]

From: Steve French <stfrench@microsoft.com>

[ Upstream commit d6fd41905ec577851734623fb905b1763801f5ef ]

We ran into a confusing problem where an application wasn't checking
return code on close and so user didn't realize that the application
ran out of disk space.  log a warning message (once) in these
cases. For example:

  [ 8407.391909] Out of space writing to \\oleg-server\small-share

Signed-off-by: Steve French <stfrench@microsoft.com>
Reported-by: Oleg Kravtsov <oleg@tuxera.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Pavel Shilovsky <pshilov@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 fs/cifs/smb2pdu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/cifs/smb2pdu.c b/fs/cifs/smb2pdu.c
index 0d4e4d97e6cf5..e2d2b749c8f38 100644
--- a/fs/cifs/smb2pdu.c
+++ b/fs/cifs/smb2pdu.c
@@ -3425,6 +3425,9 @@ smb2_writev_callback(struct mid_q_entry *mid)
 				     wdata->cfile->fid.persistent_fid,
 				     tcon->tid, tcon->ses->Suid, wdata->offset,
 				     wdata->bytes, wdata->result);
+		if (wdata->result == -ENOSPC)
+			printk_once(KERN_WARNING "Out of space writing to %s\n",
+				    tcon->treeName);
 	} else
 		trace_smb3_write_done(0 /* no xid */,
 				      wdata->cfile->fid.persistent_fid,
-- 
2.20.1