From a38ebce1da271f480e47c3def4f810c6106b74a1 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Thu, 20 Oct 2022 16:17:41 -0700 Subject: [PATCH] xfs: fix memcpy fortify errors in BUI log format copying 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 Reviewed-by: Allison Henderson Reviewed-by: Dave Chinner --- 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 51f66e9..a1da620 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; } - 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; + + 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); + 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 758702b..56917e2 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 -- 2.7.4