commit f6087fb799e097e7c9d912daa75701de9d62dc53
author Joel Becker <joel.becker@oracle.com> Mon Oct 20 18:20:43 2008 -0700
committer Mark Fasheh <mfasheh@suse.com> Mon Nov 10 09:51:44 2008 -0800
tree 010e8455fa5e53e68c76b949b4abd39876c2921f
parent c988fd045f1195e62c0970384903ab9da26a9359

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>

fs/ocfs2/xattr.c

diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c
index e19980a..151ba62 100644
--- a/fs/ocfs2/xattr.c
+++ b/fs/ocfs2/xattr.c
@@ -555,14 +555,12 @@
 		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 @@
 		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 @@
 		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 @@
 		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 @@
 		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;