On Fri, Oct 09, 2015 at 02:51:09PM -0500, Eric Sandeen wrote:
> This fixes some unaligned accesses spotted by libubsan in repair.
>
> See Documentation/unaligned-memory-access.txt in the kernel
> tree for why these can be a problem.
>
> Signed-off-by: Eric Sandeen <sandeen@xxxxxxxxxx>
> ---
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
>
> V2:
> Add note about why ...
> Add another in libxfs_bmbt_disk_get_all
> Fix mistaken double-swap in dinode.c in original patch
>
> include/libxfs.h | 4 ++--
> repair/dinode.c | 47 ++++++++++++++++++++++++-----------------------
> repair/prefetch.c | 4 ++--
> 3 files changed, 28 insertions(+), 27 deletions(-)
>
> diff --git a/include/libxfs.h b/include/libxfs.h
> index b1604e2..52fb483 100644
> --- a/include/libxfs.h
> +++ b/include/libxfs.h
> @@ -206,8 +206,8 @@ libxfs_bmbt_disk_get_all(
> {
> struct xfs_bmbt_rec_host hrec;
>
> - hrec.l0 = be64_to_cpu(rp->l0);
> - hrec.l1 = be64_to_cpu(rp->l1);
> + hrec.l0 = get_unaligned_be64(&rp->l0);
> + hrec.l1 = get_unaligned_be64(&rp->l1);
> libxfs_bmbt_get_all(&hrec, irec);
> }
>
> diff --git a/repair/dinode.c b/repair/dinode.c
> index f78f907..f99cba3 100644
> --- a/repair/dinode.c
> +++ b/repair/dinode.c
> @@ -960,15 +960,17 @@ _("bad numrecs 0 in inode %" PRIu64 " bmap btree root
> block\n"),
> * btree, we'd do it right here. For now, if there's a
> * problem, we'll bail out and presumably clear the inode.
> */
> - if (!verify_dfsbno(mp, be64_to_cpu(pp[i]))) {
> - do_warn(_("bad bmap btree ptr 0x%llx in ino %" PRIu64
> "\n"),
> - (unsigned long long) be64_to_cpu(pp[i]), lino);
> + if (!verify_dfsbno(mp, get_unaligned_be64(&pp[i]))) {
> + do_warn(
> +("bad bmap btree ptr 0x%" PRIx64 " in ino %" PRIu64 "\n"),
> + get_unaligned_be64(&pp[i]), lino);
> return(1);
> }
>
> - if (scan_lbtree(be64_to_cpu(pp[i]), level, scan_bmapbt, type,
> - whichfork, lino, tot, nex, blkmapp, &cursor,
> - 1, check_dups, magic, &xfs_bmbt_buf_ops))
> + if (scan_lbtree(get_unaligned_be64(&pp[i]), level, scan_bmapbt,
> + type, whichfork, lino, tot, nex, blkmapp,
> + &cursor, 1, check_dups, magic,
> + &xfs_bmbt_buf_ops))
> return(1);
> /*
> * fix key (offset) mismatches between the keys in root
> @@ -977,28 +979,27 @@ _("bad numrecs 0 in inode %" PRIu64 " bmap btree root
> block\n"),
> * blocks but the parent hasn't been updated
> */
> if (!check_dups && cursor.level[level-1].first_key !=
> - be64_to_cpu(pkey[i].br_startoff)) {
> + get_unaligned_be64(&pkey[i].br_startoff)) {
> if (!no_modify) {
> do_warn(
> - _("correcting key in bmbt root (was %llu, now %" PRIu64") in inode "
> - "%" PRIu64" %s fork\n"),
> - (unsigned long long)
> - be64_to_cpu(pkey[i].br_startoff),
> - cursor.level[level-1].first_key,
> - XFS_AGINO_TO_INO(mp, agno, ino),
> - forkname);
> +_("correcting key in bmbt root (was %" PRIu64 ", now %" PRIu64") in inode "
> + "%" PRIu64" %s fork\n"),
> + get_unaligned_be64(&pkey[i].br_startoff),
> + cursor.level[level-1].first_key,
> + XFS_AGINO_TO_INO(mp, agno, ino),
> + forkname);
> *dirty = 1;
> - pkey[i].br_startoff = cpu_to_be64(
> - cursor.level[level-1].first_key);
> + put_unaligned_be64(
> + cursor.level[level-1].first_key,
> + &pkey[i].br_startoff);
> } else {
> do_warn(
> - _("bad key in bmbt root (is %llu, would reset to %" PRIu64 ") in inode "
> - "%" PRIu64 " %s fork\n"),
> - (unsigned long long)
> - be64_to_cpu(pkey[i].br_startoff),
> - cursor.level[level-1].first_key,
> - XFS_AGINO_TO_INO(mp, agno, ino),
> - forkname);
> +_("bad key in bmbt root (is %" PRIu64 ", would reset to %" PRIu64 ") in
> inode "
> + "%" PRIu64 " %s fork\n"),
> + get_unaligned_be64(&pkey[i].br_startoff),
> + cursor.level[level-1].first_key,
> + XFS_AGINO_TO_INO(mp, agno, ino),
> + forkname);
> }
> }
> /*
> diff --git a/repair/prefetch.c b/repair/prefetch.c
> index 32ec55e..52238ca 100644
> --- a/repair/prefetch.c
> +++ b/repair/prefetch.c
> @@ -330,7 +330,7 @@ pf_scanfunc_bmap(
> pp = XFS_BMBT_PTR_ADDR(mp, block, 1, mp->m_bmap_dmxr[1]);
>
> for (i = 0; i < numrecs; i++) {
> - dbno = be64_to_cpu(pp[i]);
> + dbno = get_unaligned_be64(&pp[i]);
> if (!verify_dfsbno(mp, dbno))
> return 0;
> if (!pf_scan_lbtree(dbno, level, isadir, args,
> pf_scanfunc_bmap))
> @@ -372,7 +372,7 @@ pf_read_btinode(
> pp = XFS_BMDR_PTR_ADDR(dib, 1, xfs_bmdr_maxrecs(dsize, 0));
>
> for (i = 0; i < numrecs; i++) {
> - dbno = be64_to_cpu(pp[i]);
> + dbno = get_unaligned_be64(&pp[i]);
> if (!verify_dfsbno(mp, dbno))
> break;
> if (!pf_scan_lbtree(dbno, level, isadir, args,
> pf_scanfunc_bmap))
> --
> 2.6.1
>
>
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