[CIFS] Make cifs_unlink consistent in checks for null inode

Signed-off-by: Steve French <sfrench@us.ibm.com>

3 files changed, 22 insertions, 7 deletions

diff --git a/fs/cifs/CHANGES b/fs/cifs/CHANGES
index 9d1fb6ec8a5a..1bf818136276 100644
--- a/fs/cifs/CHANGES
+++ b/fs/cifs/CHANGES
@@ -1,3 +1,9 @@
+Version 1.58
+------------
+Guard against buffer overruns in various UCS-2 to UTF-8 string conversions
+when the UTF-8 string is composed of unusually long (more than 4 byte) converted
+characters.
+ 
 Version 1.57
 ------------
 Improve support for multiple security contexts to the same server. We
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index 77e190dc2883..051b71cfdea9 100644
--- a/fs/cifs/cifsfs.h
+++ b/fs/cifs/cifsfs.h
@@ -100,5 +100,5 @@ extern long cifs_ioctl(struct file *filep, unsigned int cmd, unsigned long arg);
 extern const struct export_operations cifs_export_ops;
 #endif /* EXPERIMENTAL */
 
-#define CIFS_VERSION   "1.57"
+#define CIFS_VERSION   "1.58"
 #endif                          /* _CIFSFS_H */
diff --git a/fs/cifs/inode.c b/fs/cifs/inode.c
index f36b4e40e443..9c869a6dcba1 100644
--- a/fs/cifs/inode.c
+++ b/fs/cifs/inode.c
@@ -962,13 +962,21 @@ undo_setattr:
         goto out_close;
 }
 
+
+/*
+ * If dentry->d_inode is null (usually meaning the cached dentry
+ * is a negative dentry) then we would attempt a standard SMB delete, but
+ * if that fails we can not attempt the fall back mechanisms on EACESS
+ * but will return the EACESS to the caller.  Note that the VFS does not call
+ * unlink on negative dentries currently.
+ */
 int cifs_unlink(struct inode *dir, struct dentry *dentry)
 {
         int rc = 0;
         int xid;
         char *full_path = NULL;
         struct inode *inode = dentry->d_inode;
-        struct cifsInodeInfo *cifsInode = CIFS_I(inode);
+        struct cifsInodeInfo *cifs_inode;
         struct super_block *sb = dir->i_sb;
         struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
         struct cifsTconInfo *tcon = cifs_sb->tcon;
@@ -1012,7 +1020,7 @@ psx_del_no_retry:
                 rc = cifs_rename_pending_delete(full_path, dentry, xid);
                 if (rc == 0)
                         drop_nlink(inode);
-        } else if (rc == -EACCES && dosattr == 0) {
+        } else if ((rc == -EACCES) && (dosattr == 0) && inode) {
                 attrs = kzalloc(sizeof(*attrs), GFP_KERNEL);
                 if (attrs == NULL) {
                         rc = -ENOMEM;
@@ -1020,7 +1028,8 @@ psx_del_no_retry:
                 }
 
                 /* try to reset dos attributes */
-                origattr = cifsInode->cifsAttrs;
+                cifs_inode = CIFS_I(inode);
+                origattr = cifs_inode->cifsAttrs;
                 if (origattr == 0)
                         origattr |= ATTR_NORMAL;
                 dosattr = origattr & ~ATTR_READONLY;
@@ -1041,13 +1050,13 @@ psx_del_no_retry:
 
 out_reval:
         if (inode) {
-                cifsInode = CIFS_I(inode);
-                cifsInode->time = 0;    /* will force revalidate to get info
+                cifs_inode = CIFS_I(inode);
+                cifs_inode->time = 0;   /* will force revalidate to get info
                                            when needed */
                 inode->i_ctime = current_fs_time(sb);
         }
         dir->i_ctime = dir->i_mtime = current_fs_time(sb);
-        cifsInode = CIFS_I(dir);
+        cifs_inode = CIFS_I(dir);
         CIFS_I(dir)->time = 0;  /* force revalidate of dir as well */
 
         kfree(full_path);