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>

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 35cca98..b1047de 100644 (file)
--- 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);