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authorIgor Mammedov <niallain@gmail.com>2009-02-10 14:10:26 +0300
committerSteve French <sfrench@us.ibm.com>2009-02-21 03:36:21 +0000
commite4cce94c9c8797b08faf6a79396df4d175e377fa (patch)
tree6eb306603652bf08ca10fef4f899332f30d71e09
parente1f81c8a417be466e85a38b61679aa6860ec7331 (diff)
downloadlinux-2.6.38-lt-ux500-e4cce94c9c8797b08faf6a79396df4d175e377fa.tar.gz
[CIFS] Prevent OOPs when mounting with remote prefixpath.
Fixes OOPs with message 'kernel BUG at fs/cifs/cifs_dfs_ref.c:274!'. Checks if the prefixpath in an accesible while we are still in cifs_mount and fails with reporting a error if we can't access the prefixpath Should fix Samba bugs 6086 and 5861 and kernel bug 12192 Signed-off-by: Igor Mammedov <niallain@gmail.com> Acked-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <sfrench@us.ibm.com>
-rw-r--r--fs/cifs/cifsproto.h1
-rw-r--r--fs/cifs/connect.c45
-rw-r--r--fs/cifs/inode.c4
3 files changed, 48 insertions, 2 deletions
diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
index 382ba629880..ec9f9c1c7d8 100644
--- a/fs/cifs/cifsproto.h
+++ b/fs/cifs/cifsproto.h
@@ -42,6 +42,7 @@ extern void _FreeXid(unsigned int);
#define GetXid() (int)_GetXid(); cFYI(1,("CIFS VFS: in %s as Xid: %d with uid: %d",__func__, xid,current_fsuid()));
#define FreeXid(curr_xid) {_FreeXid(curr_xid); cFYI(1,("CIFS VFS: leaving %s (xid = %d) rc = %d",__func__,curr_xid,(int)rc));}
extern char *build_path_from_dentry(struct dentry *);
+extern char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb);
extern char *build_wildcard_path_from_dentry(struct dentry *direntry);
/* extern void renew_parental_timestamps(struct dentry *direntry);*/
extern int SendReceive(const unsigned int /* xid */ , struct cifsSesInfo *,
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c
index 005df85219a..da0f4ffa061 100644
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -2180,6 +2180,33 @@ static void setup_cifs_sb(struct smb_vol *pvolume_info,
"mount option supported"));
}
+static int
+is_path_accessible(int xid, struct cifsTconInfo *tcon,
+ struct cifs_sb_info *cifs_sb, const char *full_path)
+{
+ int rc;
+ __u64 inode_num;
+ FILE_ALL_INFO *pfile_info;
+
+ rc = CIFSGetSrvInodeNumber(xid, tcon, full_path, &inode_num,
+ cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_MAP_SPECIAL_CHR);
+ if (rc != -EOPNOTSUPP)
+ return rc;
+
+ pfile_info = kmalloc(sizeof(FILE_ALL_INFO), GFP_KERNEL);
+ if (pfile_info == NULL)
+ return -ENOMEM;
+
+ rc = CIFSSMBQPathInfo(xid, tcon, full_path, pfile_info,
+ 0 /* not legacy */, cifs_sb->local_nls,
+ cifs_sb->mnt_cifs_flags &
+ CIFS_MOUNT_MAP_SPECIAL_CHR);
+ kfree(pfile_info);
+ return rc;
+}
+
int
cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
char *mount_data, const char *devname)
@@ -2190,6 +2217,7 @@ cifs_mount(struct super_block *sb, struct cifs_sb_info *cifs_sb,
struct cifsSesInfo *pSesInfo = NULL;
struct cifsTconInfo *tcon = NULL;
struct TCP_Server_Info *srvTcp = NULL;
+ char *full_path;
xid = GetXid();
@@ -2426,6 +2454,23 @@ mount_fail_check:
cifs_sb->rsize = min(cifs_sb->rsize,
(tcon->ses->server->maxBuf - MAX_CIFS_HDR_SIZE));
+ if (!rc && cifs_sb->prepathlen) {
+ /* build_path_to_root works only when we have a valid tcon */
+ full_path = cifs_build_path_to_root(cifs_sb);
+ if (full_path == NULL) {
+ rc = -ENOMEM;
+ goto mount_fail_check;
+ }
+ rc = is_path_accessible(xid, tcon, cifs_sb, full_path);
+ if (rc) {
+ cERROR(1, ("Path %s in not accessible: %d",
+ full_path, rc));
+ kfree(full_path);
+ goto mount_fail_check;
+ }
+ kfree(full_path);
+ }
+
/* volume_info->password is freed above when existing session found
(in which case it is not needed anymore) but when new sesion is created
the password ptr is put in the new session structure (in which case the
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index bcf7b518466..7342bfb02ae 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -621,7 +621,7 @@ static const struct inode_operations cifs_ipc_inode_ops = {
.lookup = cifs_lookup,
};
-static char *build_path_to_root(struct cifs_sb_info *cifs_sb)
+char *cifs_build_path_to_root(struct cifs_sb_info *cifs_sb)
{
int pplen = cifs_sb->prepathlen;
int dfsplen;
@@ -678,7 +678,7 @@ struct inode *cifs_iget(struct super_block *sb, unsigned long ino)
return inode;
cifs_sb = CIFS_SB(inode->i_sb);
- full_path = build_path_to_root(cifs_sb);
+ full_path = cifs_build_path_to_root(cifs_sb);
if (full_path == NULL)
return ERR_PTR(-ENOMEM);