xfs: validate quota log items during log recovery

Arkadiusz has seen really strange crashes in xfs_qm_dqcheck that
I can only explain by a log item being too smal to actually fit the
xfs_dqblk_t we're dereferencing all over xfs_qm_dqcheck.  So add
graceful checks for NULL or too small quota items to the log recovery
code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>

diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
index 7ba4501..47da2fb 100644 (file)
--- a/fs/xfs/xfs_log_recover.c
+++ b/fs/xfs/xfs_log_recover.c
@@ -1975,16 +1975,30 @@ xlog_recover_do_reg_buffer(
                error = 0;
                if (buf_f->blf_flags &
                   (XFS_BLI_UDQUOT_BUF|XFS_BLI_PDQUOT_BUF|XFS_BLI_GDQUOT_BUF)) {
+                       if (item->ri_buf[i].i_addr == NULL) {
+                               cmn_err(CE_ALERT,
+                                       "XFS: NULL dquot in %s.", __func__);
+                               goto next;
+                       }
+                       if (item->ri_buf[i].i_len < sizeof(xfs_dqblk_t)) {
+                               cmn_err(CE_ALERT,
+                                       "XFS: dquot too small (%d) in %s.",
+                                       item->ri_buf[i].i_len, __func__);
+                               goto next;
+                       }
                        error = xfs_qm_dqcheck((xfs_disk_dquot_t *)
                                               item->ri_buf[i].i_addr,
                                               -1, 0, XFS_QMOPT_DOWARN,
                                               "dquot_buf_recover");
+                       if (error)
+                               goto next;
                }
-               if (!error)
-                       memcpy(xfs_buf_offset(bp,
-                               (uint)bit << XFS_BLI_SHIFT),    /* dest */
-                               item->ri_buf[i].i_addr,         /* source */
-                               nbits<<XFS_BLI_SHIFT);          /* length */
+
+               memcpy(xfs_buf_offset(bp,
+                       (uint)bit << XFS_BLI_SHIFT),    /* dest */
+                       item->ri_buf[i].i_addr,         /* source */
+                       nbits<<XFS_BLI_SHIFT);          /* length */
+ next:
                i++;
                bit += nbits;
        }
@@ -2615,7 +2629,19 @@ xlog_recover_do_dquot_trans(
                return (0);
 
        recddq = (xfs_disk_dquot_t *)item->ri_buf[1].i_addr;
-       ASSERT(recddq);
+
+       if (item->ri_buf[1].i_addr == NULL) {
+               cmn_err(CE_ALERT,
+                       "XFS: NULL dquot in %s.", __func__);
+               return XFS_ERROR(EIO);
+       }
+       if (item->ri_buf[1].i_len < sizeof(xfs_dqblk_t)) {
+               cmn_err(CE_ALERT,
+                       "XFS: dquot too small (%d) in %s.",
+                       item->ri_buf[1].i_len, __func__);
+               return XFS_ERROR(EIO);
+       }
+
        /*
         * This type of quotas was turned off, so ignore this record.
         */