From: Darrick J. Wong <djwong@xxxxxxxxxx>
Starting in 6.1, CONFIG_FORTIFY_SOURCE checks the length parameter of
memcpy. Unfortunately, it doesn't handle flex arrays correctly:
------------[ cut here ]------------
memcpy: detected field-spanning write (size 48) of single field "dst_bui_fmt" at fs/xfs/xfs_bmap_item.c:628 (size 16)
Fix this by refactoring the xfs_bui_copy_format function to handle the
copying of the head and the flex array members separately. While we're
at it, fix a minor validation deficiency in the recovery function.
Signed-off-by: Darrick J. Wong <djwong@xxxxxxxxxx>
---
fs/xfs/xfs_bmap_item.c | 46 ++++++++++++++++++++++------------------------
fs/xfs/xfs_ondisk.h | 5 +++++
2 files changed, 27 insertions(+), 24 deletions(-)
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 51f66e982484..a1da6205252b 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -608,28 +608,18 @@ static const struct xfs_item_ops xfs_bui_item_ops = {
.iop_relog = xfs_bui_item_relog,
};
-/*
- * Copy an BUI format buffer from the given buf, and into the destination
- * BUI format structure. The BUI/BUD items were designed not to need any
- * special alignment handling.
- */
-static int
+static inline void
xfs_bui_copy_format(
- struct xfs_log_iovec *buf,
- struct xfs_bui_log_format *dst_bui_fmt)
+ struct xfs_bui_log_format *dst,
+ const struct xfs_bui_log_format *src)
{
- struct xfs_bui_log_format *src_bui_fmt;
- uint len;
+ unsigned int i;
- src_bui_fmt = buf->i_addr;
- len = xfs_bui_log_format_sizeof(src_bui_fmt->bui_nextents);
+ memcpy(dst, src, offsetof(struct xfs_bui_log_format, bui_extents));
- if (buf->i_len == len) {
- memcpy(dst_bui_fmt, src_bui_fmt, len);
- return 0;
- }
- XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, NULL);
- return -EFSCORRUPTED;
+ for (i = 0; i < src->bui_nextents; i++)
+ memcpy(&dst->bui_extents[i], &src->bui_extents[i],
+ sizeof(struct xfs_map_extent));
}
/*
@@ -646,23 +636,31 @@ xlog_recover_bui_commit_pass2(
struct xlog_recover_item *item,
xfs_lsn_t lsn)
{
- int error;
struct xfs_mount *mp = log->l_mp;
struct xfs_bui_log_item *buip;
struct xfs_bui_log_format *bui_formatp;
+ size_t len;
bui_formatp = item->ri_buf[0].i_addr;
+ if (item->ri_buf[0].i_len < xfs_bui_log_format_sizeof(0)) {
+ XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
+ return -EFSCORRUPTED;
+ }
+
if (bui_formatp->bui_nextents != XFS_BUI_MAX_FAST_EXTENTS) {
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
return -EFSCORRUPTED;
}
+
+ len = xfs_bui_log_format_sizeof(bui_formatp->bui_nextents);
+ if (item->ri_buf[0].i_len != len) {
+ XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
+ return -EFSCORRUPTED;
+ }
+
buip = xfs_bui_init(mp);
- error = xfs_bui_copy_format(&item->ri_buf[0], &buip->bui_format);
- if (error) {
- xfs_bui_item_free(buip);
- return error;
- }
+ xfs_bui_copy_format(&buip->bui_format, bui_formatp);
atomic_set(&buip->bui_next_extent, bui_formatp->bui_nextents);
/*
* Insert the intent into the AIL directly and drop one reference so
diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h
index 758702b9495f..56917e236370 100644
--- a/fs/xfs/xfs_ondisk.h
+++ b/fs/xfs/xfs_ondisk.h
@@ -134,6 +134,11 @@ xfs_check_ondisk_structs(void)
XFS_CHECK_STRUCT_SIZE(struct xfs_trans_header, 16);
XFS_CHECK_STRUCT_SIZE(struct xfs_attri_log_format, 40);
XFS_CHECK_STRUCT_SIZE(struct xfs_attrd_log_format, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_bui_log_format, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_bud_log_format, 16);
+ XFS_CHECK_STRUCT_SIZE(struct xfs_map_extent, 32);
+
+ XFS_CHECK_OFFSET(struct xfs_bui_log_format, bui_extents, 16);
/*
* The v5 superblock format extended several v4 header structures with
