From 9b8119cb1ed2bed648e0b3b0d5c856813a52781b Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Tue, 10 Feb 2009 14:10:26 +0300 Subject: [PATCH] [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 Signed-off-by: Igor Mammedov --- fs/cifs/cifsproto.h | 1 + fs/cifs/connect.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ fs/cifs/inode.c | 4 ++-- 3 files changed, 48 insertions(+), 2 deletions(-) diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h index 382ba62..ec9f9c1 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 005df85..da0f4ff 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 bcf7b51..7342bfb 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); -- 1.6.0.2