On Mon, Jul 16, 2018 at 02:26:55PM -0500, Bill O'Donnell wrote:
> 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>
> ---
> v2: make extra sanity checks exclusive to writes (allow read)
It looks mostly ok for me, I'm still wondering if it wouldn't be better to avoid
adding a write_flag argument for xfs_sb_verify, but I think avoiding it would
require some refactoring of the sb verify code, once we convert from BE to CPU
in xfs_sb_verify, and I'm not sure if it is worth.
So,
Reviewed-by: Carlos Maiolino <cmaiolino@xxxxxxxxxx>
>
> fs/xfs/libxfs/xfs_sb.c | 22 +++++++++++++++++-----
> 1 file changed, 17 insertions(+), 5 deletions(-)
>
> diff --git a/fs/xfs/libxfs/xfs_sb.c b/fs/xfs/libxfs/xfs_sb.c
> index 350119eeaecb..6a98ec68e8ad 100644
> --- a/fs/xfs/libxfs/xfs_sb.c
> +++ b/fs/xfs/libxfs/xfs_sb.c
> @@ -104,7 +104,8 @@ xfs_mount_validate_sb(
> xfs_mount_t *mp,
> xfs_sb_t *sbp,
> bool check_inprogress,
> - bool check_version)
> + bool check_version,
> + bool write_flag)
> {
> uint32_t agcount = 0;
> uint32_t rem;
> @@ -266,6 +267,15 @@ xfs_mount_validate_sb(
> return -EFSCORRUPTED;
> }
>
> + /* Additional sb sanity checks for writes */
> + if (write_flag) {
> + if (sbp->sb_fdblocks > sbp->sb_dblocks ||
> + sbp->sb_ifree > sbp->sb_icount) {
> + xfs_notice(mp, "SB sanity check failed");
> + return -EFSCORRUPTED;
> + }
> + }
> +
> if (sbp->sb_unit) {
> if (!xfs_sb_version_hasdalign(sbp) ||
> sbp->sb_unit > sbp->sb_width ||
> @@ -599,7 +609,9 @@ xfs_sb_to_disk(
> static int
> xfs_sb_verify(
> struct xfs_buf *bp,
> - bool check_version)
> + bool check_version,
> + bool write_flag)
> +
> {
> struct xfs_mount *mp = bp->b_target->bt_mount;
> struct xfs_sb sb;
> @@ -616,7 +628,7 @@ xfs_sb_verify(
> */
> return xfs_mount_validate_sb(mp, &sb,
> bp->b_maps[0].bm_bn == XFS_SB_DADDR,
> - check_version);
> + check_version, write_flag);
> }
>
> /*
> @@ -657,7 +669,7 @@ xfs_sb_read_verify(
> }
> }
> }
> - error = xfs_sb_verify(bp, true);
> + error = xfs_sb_verify(bp, true, false);
>
> out_error:
> if (error == -EFSCORRUPTED || error == -EFSBADCRC)
> @@ -695,7 +707,7 @@ xfs_sb_write_verify(
> struct xfs_buf_log_item *bip = bp->b_log_item;
> int error;
>
> - error = xfs_sb_verify(bp, false);
> + error = xfs_sb_verify(bp, false, true);
> if (error) {
> xfs_verifier_error(bp, error, __this_address);
> return;
> --
> 2.17.1
>
> --
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--
Carlos
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