Message ID | 20190207184105.17064-4-bfoster@redhat.com (mailing list archive) |
---|---|
State | Accepted |
Headers | show |
Series | xfs: fix [f]inobt magic value verification | expand |
On Thu, Feb 07, 2019 at 01:41:00PM -0500, Brian Foster wrote: > The inode btree verifier code is shared between the inode btree and > free inode btree because the underlying metadata formats are > essentially equivalent. A side effect of this is that the verifier > cannot determine whether a particular btree block should have an > inobt or finobt magic value. > > This logic allows an unfortunate xfs_repair bug to escape detection > where certain level > 0 nodes of the finobt are stamped with inobt > magic by xfs_repair finobt reconstruction. This is fortunately not a > severe problem since the inode btree magic values do not contribute > to any changes in kernel behavior, but we do need a means to detect > and prevent this problem in the future. > > Add a field to xfs_buf_ops to store the v4 and v5 superblock magic > values expected by a particular verifier. Add a helper to check an > on-disk magic value against the value expected by the verifier. Call > the helper from the shared [f]inobt verifier code for magic value > verification. This ensures that the inode btree blocks each have the > appropriate magic value based on specific tree type and superblock > version. > > Signed-off-by: Brian Foster <bfoster@redhat.com> > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > --- > fs/xfs/libxfs/xfs_ialloc_btree.c | 16 +++++++--------- > fs/xfs/xfs_buf.c | 19 +++++++++++++++++++ > fs/xfs/xfs_buf.h | 2 ++ > 3 files changed, 28 insertions(+), 9 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c > index 798269eb4767..c2df1f89eec8 100644 > --- a/fs/xfs/libxfs/xfs_ialloc_btree.c > +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c > @@ -260,6 +260,9 @@ xfs_inobt_verify( > xfs_failaddr_t fa; > unsigned int level; > > + if (!xfs_verify_magic(bp, block->bb_magic)) > + return __this_address; > + > /* > * During growfs operations, we can't verify the exact owner as the > * perag is not fully initialised and hence not attached to the buffer. > @@ -270,18 +273,10 @@ xfs_inobt_verify( > * but beware of the landmine (i.e. need to check pag->pagi_init) if we > * ever do. > */ > - switch (block->bb_magic) { > - case cpu_to_be32(XFS_IBT_CRC_MAGIC): > - case cpu_to_be32(XFS_FIBT_CRC_MAGIC): > + if (xfs_sb_version_hascrc(&mp->m_sb)) { > fa = xfs_btree_sblock_v5hdr_verify(bp); > if (fa) > return fa; > - /* fall through */ > - case cpu_to_be32(XFS_IBT_MAGIC): > - case cpu_to_be32(XFS_FIBT_MAGIC): > - break; > - default: > - return __this_address; > } > > /* level verification */ > @@ -328,6 +323,7 @@ xfs_inobt_write_verify( > > const struct xfs_buf_ops xfs_inobt_buf_ops = { > .name = "xfs_inobt", > + .magic = { cpu_to_be32(XFS_IBT_MAGIC), cpu_to_be32(XFS_IBT_CRC_MAGIC) }, > .verify_read = xfs_inobt_read_verify, > .verify_write = xfs_inobt_write_verify, > .verify_struct = xfs_inobt_verify, > @@ -335,6 +331,8 @@ const struct xfs_buf_ops xfs_inobt_buf_ops = { > > const struct xfs_buf_ops xfs_finobt_buf_ops = { > .name = "xfs_finobt", > + .magic = { cpu_to_be32(XFS_FIBT_MAGIC), > + cpu_to_be32(XFS_FIBT_CRC_MAGIC) }, > .verify_read = xfs_inobt_read_verify, > .verify_write = xfs_inobt_write_verify, > .verify_struct = xfs_inobt_verify, > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > index e1c5be26bf9f..c9cf8c0c7d32 100644 > --- a/fs/xfs/xfs_buf.c > +++ b/fs/xfs/xfs_buf.c > @@ -2203,3 +2203,22 @@ void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) > > atomic_set(&bp->b_lru_ref, lru_ref); > } > + > +/* > + * Verify an on-disk magic value against the magic value specified in the > + * verifier structure. The verifier magic is in disk byte order so the caller is > + * expected to pass the value directly from disk. > + */ > +bool > +xfs_verify_magic( > + struct xfs_buf *bp, > + uint32_t dmagic) It occurred to me that this probably ought to be __be32 since we're encoding the magics in disk byte order, right? > +{ > + struct xfs_mount *mp = bp->b_target->bt_mount; > + int idx; > + > + idx = xfs_sb_version_hascrc(&mp->m_sb); > + if (unlikely(WARN_ON(!bp->b_ops || !bp->b_ops->magic[idx]))) > + return false; > + return dmagic == bp->b_ops->magic[idx]; > +} > diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h > index 1c436a85b71d..44f9423a1861 100644 > --- a/fs/xfs/xfs_buf.h > +++ b/fs/xfs/xfs_buf.h > @@ -125,6 +125,7 @@ struct xfs_buf_map { > > struct xfs_buf_ops { > char *name; > + uint32_t magic[2]; /* v4 and v5 on disk magic values */ Here too? --D > void (*verify_read)(struct xfs_buf *); > void (*verify_write)(struct xfs_buf *); > xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp); > @@ -386,5 +387,6 @@ extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); > #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) > > int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops); > +bool xfs_verify_magic(struct xfs_buf *bp, uint32_t dmagic); > > #endif /* __XFS_BUF_H__ */ > -- > 2.17.2 >
On Thu, Feb 07, 2019 at 10:52:09AM -0800, Darrick J. Wong wrote: > On Thu, Feb 07, 2019 at 01:41:00PM -0500, Brian Foster wrote: > > The inode btree verifier code is shared between the inode btree and > > free inode btree because the underlying metadata formats are > > essentially equivalent. A side effect of this is that the verifier > > cannot determine whether a particular btree block should have an > > inobt or finobt magic value. > > > > This logic allows an unfortunate xfs_repair bug to escape detection > > where certain level > 0 nodes of the finobt are stamped with inobt > > magic by xfs_repair finobt reconstruction. This is fortunately not a > > severe problem since the inode btree magic values do not contribute > > to any changes in kernel behavior, but we do need a means to detect > > and prevent this problem in the future. > > > > Add a field to xfs_buf_ops to store the v4 and v5 superblock magic > > values expected by a particular verifier. Add a helper to check an > > on-disk magic value against the value expected by the verifier. Call > > the helper from the shared [f]inobt verifier code for magic value > > verification. This ensures that the inode btree blocks each have the > > appropriate magic value based on specific tree type and superblock > > version. > > > > Signed-off-by: Brian Foster <bfoster@redhat.com> > > Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> > > --- > > fs/xfs/libxfs/xfs_ialloc_btree.c | 16 +++++++--------- > > fs/xfs/xfs_buf.c | 19 +++++++++++++++++++ > > fs/xfs/xfs_buf.h | 2 ++ > > 3 files changed, 28 insertions(+), 9 deletions(-) > > > > diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c > > index 798269eb4767..c2df1f89eec8 100644 > > --- a/fs/xfs/libxfs/xfs_ialloc_btree.c > > +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c > > @@ -260,6 +260,9 @@ xfs_inobt_verify( > > xfs_failaddr_t fa; > > unsigned int level; > > > > + if (!xfs_verify_magic(bp, block->bb_magic)) > > + return __this_address; > > + > > /* > > * During growfs operations, we can't verify the exact owner as the > > * perag is not fully initialised and hence not attached to the buffer. > > @@ -270,18 +273,10 @@ xfs_inobt_verify( > > * but beware of the landmine (i.e. need to check pag->pagi_init) if we > > * ever do. > > */ > > - switch (block->bb_magic) { > > - case cpu_to_be32(XFS_IBT_CRC_MAGIC): > > - case cpu_to_be32(XFS_FIBT_CRC_MAGIC): > > + if (xfs_sb_version_hascrc(&mp->m_sb)) { > > fa = xfs_btree_sblock_v5hdr_verify(bp); > > if (fa) > > return fa; > > - /* fall through */ > > - case cpu_to_be32(XFS_IBT_MAGIC): > > - case cpu_to_be32(XFS_FIBT_MAGIC): > > - break; > > - default: > > - return __this_address; > > } > > > > /* level verification */ > > @@ -328,6 +323,7 @@ xfs_inobt_write_verify( > > > > const struct xfs_buf_ops xfs_inobt_buf_ops = { > > .name = "xfs_inobt", > > + .magic = { cpu_to_be32(XFS_IBT_MAGIC), cpu_to_be32(XFS_IBT_CRC_MAGIC) }, > > .verify_read = xfs_inobt_read_verify, > > .verify_write = xfs_inobt_write_verify, > > .verify_struct = xfs_inobt_verify, > > @@ -335,6 +331,8 @@ const struct xfs_buf_ops xfs_inobt_buf_ops = { > > > > const struct xfs_buf_ops xfs_finobt_buf_ops = { > > .name = "xfs_finobt", > > + .magic = { cpu_to_be32(XFS_FIBT_MAGIC), > > + cpu_to_be32(XFS_FIBT_CRC_MAGIC) }, > > .verify_read = xfs_inobt_read_verify, > > .verify_write = xfs_inobt_write_verify, > > .verify_struct = xfs_inobt_verify, > > diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c > > index e1c5be26bf9f..c9cf8c0c7d32 100644 > > --- a/fs/xfs/xfs_buf.c > > +++ b/fs/xfs/xfs_buf.c > > @@ -2203,3 +2203,22 @@ void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) > > > > atomic_set(&bp->b_lru_ref, lru_ref); > > } > > + > > +/* > > + * Verify an on-disk magic value against the magic value specified in the > > + * verifier structure. The verifier magic is in disk byte order so the caller is > > + * expected to pass the value directly from disk. > > + */ > > +bool > > +xfs_verify_magic( > > + struct xfs_buf *bp, > > + uint32_t dmagic) > > It occurred to me that this probably ought to be __be32 since we're > encoding the magics in disk byte order, right? > This crossed my mind when I originally changed it from cpu endian to on-disk endian, but not all of these magic values are even 32-bit. It seemed more appropriate to me to just use something more opaque (which I figured was still uint32_t, but could very well be something else). Brian > > +{ > > + struct xfs_mount *mp = bp->b_target->bt_mount; > > + int idx; > > + > > + idx = xfs_sb_version_hascrc(&mp->m_sb); > > + if (unlikely(WARN_ON(!bp->b_ops || !bp->b_ops->magic[idx]))) > > + return false; > > + return dmagic == bp->b_ops->magic[idx]; > > +} > > diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h > > index 1c436a85b71d..44f9423a1861 100644 > > --- a/fs/xfs/xfs_buf.h > > +++ b/fs/xfs/xfs_buf.h > > @@ -125,6 +125,7 @@ struct xfs_buf_map { > > > > struct xfs_buf_ops { > > char *name; > > + uint32_t magic[2]; /* v4 and v5 on disk magic values */ > > Here too? > > --D > > > void (*verify_read)(struct xfs_buf *); > > void (*verify_write)(struct xfs_buf *); > > xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp); > > @@ -386,5 +387,6 @@ extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); > > #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) > > > > int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops); > > +bool xfs_verify_magic(struct xfs_buf *bp, uint32_t dmagic); > > > > #endif /* __XFS_BUF_H__ */ > > -- > > 2.17.2 > >
diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c index 798269eb4767..c2df1f89eec8 100644 --- a/fs/xfs/libxfs/xfs_ialloc_btree.c +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c @@ -260,6 +260,9 @@ xfs_inobt_verify( xfs_failaddr_t fa; unsigned int level; + if (!xfs_verify_magic(bp, block->bb_magic)) + return __this_address; + /* * During growfs operations, we can't verify the exact owner as the * perag is not fully initialised and hence not attached to the buffer. @@ -270,18 +273,10 @@ xfs_inobt_verify( * but beware of the landmine (i.e. need to check pag->pagi_init) if we * ever do. */ - switch (block->bb_magic) { - case cpu_to_be32(XFS_IBT_CRC_MAGIC): - case cpu_to_be32(XFS_FIBT_CRC_MAGIC): + if (xfs_sb_version_hascrc(&mp->m_sb)) { fa = xfs_btree_sblock_v5hdr_verify(bp); if (fa) return fa; - /* fall through */ - case cpu_to_be32(XFS_IBT_MAGIC): - case cpu_to_be32(XFS_FIBT_MAGIC): - break; - default: - return __this_address; } /* level verification */ @@ -328,6 +323,7 @@ xfs_inobt_write_verify( const struct xfs_buf_ops xfs_inobt_buf_ops = { .name = "xfs_inobt", + .magic = { cpu_to_be32(XFS_IBT_MAGIC), cpu_to_be32(XFS_IBT_CRC_MAGIC) }, .verify_read = xfs_inobt_read_verify, .verify_write = xfs_inobt_write_verify, .verify_struct = xfs_inobt_verify, @@ -335,6 +331,8 @@ const struct xfs_buf_ops xfs_inobt_buf_ops = { const struct xfs_buf_ops xfs_finobt_buf_ops = { .name = "xfs_finobt", + .magic = { cpu_to_be32(XFS_FIBT_MAGIC), + cpu_to_be32(XFS_FIBT_CRC_MAGIC) }, .verify_read = xfs_inobt_read_verify, .verify_write = xfs_inobt_write_verify, .verify_struct = xfs_inobt_verify, diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c index e1c5be26bf9f..c9cf8c0c7d32 100644 --- a/fs/xfs/xfs_buf.c +++ b/fs/xfs/xfs_buf.c @@ -2203,3 +2203,22 @@ void xfs_buf_set_ref(struct xfs_buf *bp, int lru_ref) atomic_set(&bp->b_lru_ref, lru_ref); } + +/* + * Verify an on-disk magic value against the magic value specified in the + * verifier structure. The verifier magic is in disk byte order so the caller is + * expected to pass the value directly from disk. + */ +bool +xfs_verify_magic( + struct xfs_buf *bp, + uint32_t dmagic) +{ + struct xfs_mount *mp = bp->b_target->bt_mount; + int idx; + + idx = xfs_sb_version_hascrc(&mp->m_sb); + if (unlikely(WARN_ON(!bp->b_ops || !bp->b_ops->magic[idx]))) + return false; + return dmagic == bp->b_ops->magic[idx]; +} diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h index 1c436a85b71d..44f9423a1861 100644 --- a/fs/xfs/xfs_buf.h +++ b/fs/xfs/xfs_buf.h @@ -125,6 +125,7 @@ struct xfs_buf_map { struct xfs_buf_ops { char *name; + uint32_t magic[2]; /* v4 and v5 on disk magic values */ void (*verify_read)(struct xfs_buf *); void (*verify_write)(struct xfs_buf *); xfs_failaddr_t (*verify_struct)(struct xfs_buf *bp); @@ -386,5 +387,6 @@ extern int xfs_setsize_buftarg(xfs_buftarg_t *, unsigned int); #define xfs_readonly_buftarg(buftarg) bdev_read_only((buftarg)->bt_bdev) int xfs_buf_reverify(struct xfs_buf *bp, const struct xfs_buf_ops *ops); +bool xfs_verify_magic(struct xfs_buf *bp, uint32_t dmagic); #endif /* __XFS_BUF_H__ */