From: Nathan Scott <nathans@sgi.com>
Date: Tue, 14 May 2002 06:27:01 +0000 (+0000)
Subject: Fix a use-after-free bug in xfs_repair code for checking version 1
X-Git-Tag: v2.1.0~28
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=948ce18;p=thirdparty%2Fxfsprogs-dev.git

Fix a use-after-free bug in xfs_repair code for checking version 1
btree-format directories.  Found by libefence.a in conjunction with
the qa tests on <pgsize blocksize filesystems.
---

diff --git a/doc/CHANGES b/doc/CHANGES
index 8e901dea9..30a9291a9 100644
--- a/doc/CHANGES
+++ b/doc/CHANGES
@@ -5,6 +5,8 @@
 	- Fix bug in xfs_repair da_write() routine, which affects
 	  filesystems where the data blocksize != naming blocksize
 	  (see xfs_info output).
+	- Fix a use-after-free bug in xfs_repair code for checking
+	  version 1 btree-format directories.
 
 xfsprogs-2.0.5 (02 May 2002)
 	- size AGs so that they do not always start on the same 
diff --git a/repair/dir.c b/repair/dir.c
index 7fd0d2c3c..555e5e1fa 100644
--- a/repair/dir.c
+++ b/repair/dir.c
@@ -1035,6 +1035,7 @@ verify_final_da_path(xfs_mount_t	*mp,
 		const int		p_level)
 {
 	xfs_da_intnode_t	*node;
+	xfs_dahash_t		hashval;
 	int			bad = 0;
 	int			entry;
 	int			this_level = p_level + 1;
@@ -1117,6 +1118,12 @@ verify_final_da_path(xfs_mount_t	*mp,
 		}
 	}
 
+	/*
+	 * Note: squirrel hashval away _before_ releasing the
+	 * buffer, preventing a use-after-free problem.
+	 */
+	hashval = INT_GET(node->btree[entry].hashval, ARCH_CONVERT);
+
 	/*
 	 * release/write buffer
 	 */
@@ -1140,11 +1147,10 @@ verify_final_da_path(xfs_mount_t	*mp,
 		return(0);
 	}
 	/*
-	 * set hashvalue to correctl reflect the now-validated
+	 * set hashvalue to correctly reflect the now-validated
 	 * last entry in this block and continue upwards validation
 	 */
-	cursor->level[this_level].hashval =
-			INT_GET(node->btree[entry].hashval, ARCH_CONVERT);
+	cursor->level[this_level].hashval = hashval;
 	return(verify_final_da_path(mp, cursor, this_level));
 }