ocfs2: Check xattr block signatures properly.

The xattr.c code is currently memcmp()ing naking buffer pointers.
Create the OCFS2_IS_VALID_XATTR_BLOCK() macro to match its peers and use
that.

In addition, failed signature checks were returning -EFAULT, which is
completely wrong.  Return -EIO.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.com>

diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index a21a465490c40d0ee0ef3fc3d554d9f2196bdac2..fef7ece32376f65ef9af2a455fc4b623519819ec 100644 (file)
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -473,6 +473,9 @@ static inline int ocfs2_uses_extended_slot_map(struct ocfs2_super *osb)
                (____gd)->bg_signature);                                \
 } while (0)
 
+#define OCFS2_IS_VALID_XATTR_BLOCK(ptr)                                        \
+       (!strcmp((ptr)->xb_signature, OCFS2_XATTR_BLOCK_SIGNATURE))
+
 static inline unsigned long ino_from_blkno(struct super_block *sb,
                                           u64 blkno)
 {

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index e19980a71a3c418e8eb70f3ea3529762223dbf58..151ba6257fbb6619fb731db72665358d5841725f 100644 (file)
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -555,14 +555,12 @@ static int ocfs2_xattr_block_list(struct inode *inode,
                mlog_errno(ret);
                return ret;
        }
-       /*Verify the signature of xattr block*/
-       if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
-                  strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
-               ret = -EFAULT;
-               goto cleanup;
-       }
 
        xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+       if (!OCFS2_IS_VALID_XATTR_BLOCK(xb)) {
+               ret = -EIO;
+               goto cleanup;
+       }
 
        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                struct ocfs2_xattr_header *header = &xb->xb_attrs.xb_header;
@@ -779,15 +777,14 @@ static int ocfs2_xattr_block_get(struct inode *inode,
                mlog_errno(ret);
                return ret;
        }
-       /*Verify the signature of xattr block*/
-       if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
-                  strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
-               ret = -EFAULT;
+
+       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+       if (!OCFS2_IS_VALID_XATTR_BLOCK(xb)) {
+               ret = -EIO;
                goto cleanup;
        }
 
        xs->xattr_bh = blk_bh;
-       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
 
        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                xs->header = &xb->xb_attrs.xb_header;
@@ -1527,10 +1524,9 @@ static int ocfs2_xattr_free_block(struct inode *inode,
                goto out;
        }
 
-       /*Verify the signature of xattr block*/
-       if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
-                  strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
-               ret = -EFAULT;
+       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+       if (!OCFS2_IS_VALID_XATTR_BLOCK(xb)) {
+               ret = -EIO;
                goto out;
        }
 
@@ -1540,7 +1536,6 @@ static int ocfs2_xattr_free_block(struct inode *inode,
                goto out;
        }
 
-       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
        blk = le64_to_cpu(xb->xb_blkno);
        bit = le16_to_cpu(xb->xb_suballoc_bit);
        bg_blkno = ocfs2_which_suballoc_group(blk, bit);
@@ -1784,15 +1779,14 @@ static int ocfs2_xattr_block_find(struct inode *inode,
                mlog_errno(ret);
                return ret;
        }
-       /*Verify the signature of xattr block*/
-       if (memcmp((void *)blk_bh->b_data, OCFS2_XATTR_BLOCK_SIGNATURE,
-                  strlen(OCFS2_XATTR_BLOCK_SIGNATURE))) {
-                       ret = -EFAULT;
-                       goto cleanup;
+
+       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
+       if (!OCFS2_IS_VALID_XATTR_BLOCK(xb)) {
+               ret = -EIO;
+               goto cleanup;
        }
 
        xs->xattr_bh = blk_bh;
-       xb = (struct ocfs2_xattr_block *)blk_bh->b_data;
 
        if (!(le16_to_cpu(xb->xb_flags) & OCFS2_XATTR_INDEXED)) {
                xs->header = &xb->xb_attrs.xb_header;