xfs: Check buffer lengths in log recovery

Before trying to obtain, read or write a buffer,
check that the buffer length is actually valid. If
it is not valid, then something read in the recovery
process has been corrupted and we should abort
recovery.

Reported-by: Eric Sesterhenn <snakebyte@gmx.de>
Tested-by: Eric Sesterhenn <snakebyte@gmx.de>
Reviewed-by: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Felix Blyakher <felixb@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Felix Blyakher <felixb@sgi.com>

1 files changed, 25 insertions, 6 deletions

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 35cca98bd94c..b1047de2fffd 100644
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -70,16 +70,21 @@ STATIC void	xlog_recover_check_summary(xlog_t *);
 xfs_buf_t *
 xlog_get_bp(
         xlog_t          *log,
-        int             num_bblks)
+        int             nbblks)
 {
-        ASSERT(num_bblks > 0);
+        if (nbblks <= 0 || nbblks > log->l_logBBsize) {
+                xlog_warn("XFS: Invalid block length (0x%x) given for buffer", nbblks);
+                XFS_ERROR_REPORT("xlog_get_bp(1)",
+                                 XFS_ERRLEVEL_HIGH, log->l_mp);
+                return NULL;
+        }
 
         if (log->l_sectbb_log) {
-                if (num_bblks > 1)
-                        num_bblks += XLOG_SECTOR_ROUNDUP_BBCOUNT(log, 1);
-                num_bblks = XLOG_SECTOR_ROUNDUP_BBCOUNT(log, num_bblks);
+                if (nbblks > 1)
+                        nbblks += XLOG_SECTOR_ROUNDUP_BBCOUNT(log, 1);
+                nbblks = XLOG_SECTOR_ROUNDUP_BBCOUNT(log, nbblks);
         }
-        return xfs_buf_get_noaddr(BBTOB(num_bblks), log->l_mp->m_logdev_targp);
+        return xfs_buf_get_noaddr(BBTOB(nbblks), log->l_mp->m_logdev_targp);
 }
 
 void
@@ -102,6 +107,13 @@ xlog_bread(
 {
         int             error;
 
+        if (nbblks <= 0 || nbblks > log->l_logBBsize) {
+                xlog_warn("XFS: Invalid block length (0x%x) given for buffer", nbblks);
+                XFS_ERROR_REPORT("xlog_bread(1)",
+                                 XFS_ERRLEVEL_HIGH, log->l_mp);
+                return EFSCORRUPTED;
+        }
+
         if (log->l_sectbb_log) {
                 blk_no = XLOG_SECTOR_ROUNDDOWN_BLKNO(log, blk_no);
                 nbblks = XLOG_SECTOR_ROUNDUP_BBCOUNT(log, nbblks);
@@ -139,6 +151,13 @@ xlog_bwrite(
 {
         int             error;
 
+        if (nbblks <= 0 || nbblks > log->l_logBBsize) {
+                xlog_warn("XFS: Invalid block length (0x%x) given for buffer", nbblks);
+                XFS_ERROR_REPORT("xlog_bwrite(1)",
+                                 XFS_ERRLEVEL_HIGH, log->l_mp);
+                return EFSCORRUPTED;
+        }
+
         if (log->l_sectbb_log) {
                 blk_no = XLOG_SECTOR_ROUNDDOWN_BLKNO(log, blk_no);
                 nbblks = XLOG_SECTOR_ROUNDUP_BBCOUNT(log, nbblks);