Current sb verifier doesn't check bounds on sb_fdblocks and sb_ifree.
Add sanity checks for these parameters.
Signed-off-by: Bill O'Donnell <billodo@xxxxxxxxxx>
---
v4: adjust control flow to standard error checking. Add
more descriptive comment. Add validation for sb_icount.
v3: eliminate need for additional write_flag, doing those
unique checks in xfs_sb_write_verify()
v2: make extra sanity checks exclusive to writes
fs/xfs/libxfs/xfs_sb.c | 46 +++++++++++++++++++++++++++++++++---------
1 file changed, 36 insertions(+), 10 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
index b3ad15956366..8d8e579ca426 100644
--- a/fs/xfs/libxfs/xfs_sb.c
+++ b/fs/xfs/libxfs/xfs_sb.c
@@ -599,22 +599,16 @@ xfs_sb_to_disk(
static int
xfs_sb_verify(
struct xfs_buf *bp,
+ struct xfs_sb *sb,
bool check_version)
{
struct xfs_mount *mp = bp->b_target->bt_mount;
- struct xfs_sb sb;
-
- /*
- * Use call variant which doesn't convert quota flags from disk
- * format, because xfs_mount_validate_sb checks the on-disk flags.
- */
- __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false);
/*
* Only check the in progress field for the primary superblock as
* mkfs.xfs doesn't clear it from secondary superblocks.
*/
- return xfs_mount_validate_sb(mp, &sb,
+ return xfs_mount_validate_sb(mp, sb,
bp->b_maps[0].bm_bn == XFS_SB_DADDR,
check_version);
}
@@ -637,6 +631,7 @@ xfs_sb_read_verify(
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_dsb *dsb = XFS_BUF_TO_SBP(bp);
+ struct xfs_sb sb;
int error;
/*
@@ -657,7 +652,13 @@ xfs_sb_read_verify(
}
}
}
- error = xfs_sb_verify(bp, true);
+
+ /*
+ * Use call variant which doesn't convert quota flags from disk
+ * format, because xfs_mount_validate_sb checks the on-disk flags.
+ */
+ __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false);
+ error = xfs_sb_verify(bp, &sb, true);
out_error:
if (error == -EFSCORRUPTED || error == -EFSBADCRC)
@@ -693,9 +694,34 @@ xfs_sb_write_verify(
{
struct xfs_mount *mp = bp->b_target->bt_mount;
struct xfs_buf_log_item *bip = bp->b_log_item;
+ struct xfs_sb sb;
int error;
- error = xfs_sb_verify(bp, false);
+ /*
+ * Use call variant which doesn't convert quota flags from disk
+ * format, because xfs_mount_validate_sb checks the on-disk flags.
+ */
+ __xfs_sb_from_disk(&sb, XFS_BUF_TO_SBP(bp), false);
+
+ error = xfs_sb_verify(bp, &sb, false);
+ if (error)
+ goto err;
+
+ /*
+ * Carry out additional sb sanity checks exclusively for writes.
+ * We don't do these checks for reads, since faulty parameters could
+ * already be on disk, and we shouldn't preclude reads for those
+ * cases.
+ */
+ if (sb.sb_fdblocks > sb.sb_dblocks ||
+ sb.sb_icount / sb.sb_inopblock > sb.sb_dblocks ||
+ sb.sb_ifree > sb.sb_icount) {
+ xfs_notice(mp, "SB sanity check failed");
+ error = -EFSCORRUPTED;
+ goto err;
+ }
+
+err:
if (error) {
xfs_verifier_error(bp, error, __this_address);
return;
--
2.17.1
--
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