From 15b253eace1f98dabbc6e03f6793fcf8603b1655 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Sat, 2 Jul 2016 05:43:46 +0100 Subject: [PATCH] Btrfs: send, avoid incorrect leaf accesses when sending utimes operations The caller of send_utimes() is supposed to be sure that the inode number it passes to this function does actually exists in the send snapshot. However due to logic/algorithm bugs (such as the one fixed by the patch titled "Btrfs: send, fix invalid leaf accesses due to incorrect utimes operations"), this might not be the case and when that happens it makes send_utimes() access use an unrelated leaf item as the target inode item or access beyond a leaf's boundaries (when the leaf is full and path->slots[0] matches the number of items in the leaf). So if the call to btrfs_search_slot() done by send_utimes() does not find the inode item, just make sure send_utimes() returns -ENOENT and does not silently accesses unrelated leaf items or does invalid leaf accesses, also allowing us to easialy and deterministically catch such algorithmic/logic bugs. Signed-off-by: Filipe Manana --- fs/btrfs/send.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 8b653967b163..2db8dc89ca41 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -2502,6 +2502,8 @@ verbose_printk("btrfs: send_utimes %llu\n", ino); key.type = BTRFS_INODE_ITEM_KEY; key.offset = 0; ret = btrfs_search_slot(NULL, sctx->send_root, &key, path, 0, 0); + if (ret > 0) + ret = -ENOENT; if (ret < 0) goto out; -- 2.20.1