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xfs: strengthen btree pointer checks before use

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Instead of ASSERTing on null btree pointers in xfs_btree_ptr_to_daddr,
use the new block number verifiers to ensure that the btree pointer
doesn't point to any sensitive areas (AG headers, past-EOFS) and return
-EFSCORRUPTED if this is the case.  Remove the ASSERT because on-disk
corruptions shouldn't trigger ASSERTs.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
This commit is contained in:
Darrick J. Wong 2018-06-04 13:58:34 -07:00
parent 4cbae4b816
commit e63a1008ee
1 changed files with 35 additions and 15 deletions
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50
fs/xfs/libxfs/xfs_btree.c
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@ -992,22 +992,30 @@ xfs_btree_readahead(
return xfs_btree_readahead_sblock(cur, lr, block);
}
STATIC xfs_daddr_t
STATIC int
xfs_btree_ptr_to_daddr(
struct xfs_btree_cur *cur,
union xfs_btree_ptr *ptr)
union xfs_btree_ptr *ptr,
xfs_daddr_t *daddr)
{
xfs_fsblock_t fsbno;
xfs_agblock_t agbno;
int error;
error = xfs_btree_check_ptr(cur, ptr, 0, 1);
if (error)
return error;
if (cur->bc_flags & XFS_BTREE_LONG_PTRS) {
ASSERT(ptr->l != cpu_to_be64(NULLFSBLOCK));
return XFS_FSB_TO_DADDR(cur->bc_mp, be64_to_cpu(ptr->l));
fsbno = be64_to_cpu(ptr->l);
*daddr = XFS_FSB_TO_DADDR(cur->bc_mp, fsbno);
} else {
ASSERT(cur->bc_private.a.agno != NULLAGNUMBER);
ASSERT(ptr->s != cpu_to_be32(NULLAGBLOCK));
return XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
be32_to_cpu(ptr->s));
agbno = be32_to_cpu(ptr->s);
*daddr = XFS_AGB_TO_DADDR(cur->bc_mp, cur->bc_private.a.agno,
agbno);
}
return 0;
}
/*
@ -1022,8 +1030,11 @@ xfs_btree_readahead_ptr(
union xfs_btree_ptr *ptr,
xfs_extlen_t count)
{
xfs_buf_readahead(cur->bc_mp->m_ddev_targp,
xfs_btree_ptr_to_daddr(cur, ptr),
xfs_daddr_t daddr;
if (xfs_btree_ptr_to_daddr(cur, ptr, &daddr))
return;
xfs_buf_readahead(cur->bc_mp->m_ddev_targp, daddr,
cur->bc_mp->m_bsize * count, cur->bc_ops->buf_ops);
}
@ -1286,11 +1297,14 @@ xfs_btree_get_buf_block(
{
struct xfs_mount *mp = cur->bc_mp;
xfs_daddr_t d;
int error;
/* need to sort out how callers deal with failures first */
ASSERT(!(flags & XBF_TRYLOCK));
d = xfs_btree_ptr_to_daddr(cur, ptr);
error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
if (error)
return error;
*bpp = xfs_trans_get_buf(cur->bc_tp, mp->m_ddev_targp, d,
mp->m_bsize, flags);
@ -1321,7 +1335,9 @@ xfs_btree_read_buf_block(
/* need to sort out how callers deal with failures first */
ASSERT(!(flags & XBF_TRYLOCK));
d = xfs_btree_ptr_to_daddr(cur, ptr);
error = xfs_btree_ptr_to_daddr(cur, ptr, &d);
if (error)
return error;
error = xfs_trans_read_buf(mp, cur->bc_tp, mp->m_ddev_targp, d,
mp->m_bsize, flags, bpp,
cur->bc_ops->buf_ops);
@ -1768,6 +1784,7 @@ xfs_btree_lookup_get_block(
struct xfs_btree_block **blkp) /* return btree block */
{
struct xfs_buf *bp; /* buffer pointer for btree block */
xfs_daddr_t daddr;
int error = 0;
/* special case the root block if in an inode */
@ -1784,7 +1801,10 @@ xfs_btree_lookup_get_block(
* Otherwise throw it away and get a new one.
*/
bp = cur->bc_bufs[level];
if (bp && XFS_BUF_ADDR(bp) == xfs_btree_ptr_to_daddr(cur, pp)) {
error = xfs_btree_ptr_to_daddr(cur, pp, &daddr);
if (error)
return error;
if (bp && XFS_BUF_ADDR(bp) == daddr) {
*blkp = XFS_BUF_TO_BLOCK(bp);
return 0;
}