[PATCH AUTOSEL 5.15 18/20] btrfs: send: handle path ref underflow in header iterate_inode_ref()

[Sasha Levin]

From: David Sterba <dsterba@xxxxxxxx>

[ Upstream commit 3c6ee34c6f9cd12802326da26631232a61743501 ]

Change BUG_ON to proper error handling if building the path buffer
fails. The pointers are not printed so we don't accidentally leak kernel
addresses.

Signed-off-by: David Sterba <dsterba@xxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 fs/btrfs/send.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c
index 9900f879fa346..f1ef176a64242 100644
--- a/fs/btrfs/send.c
+++ b/fs/btrfs/send.c
@@ -976,7 +976,15 @@ static int iterate_inode_ref(struct btrfs_root *root, struct btrfs_path *path,
 					ret = PTR_ERR(start);
 					goto out;
 				}
-				BUG_ON(start < p->buf);
+				if (unlikely(start < p->buf)) {
+					btrfs_err(root->fs_info,
+			"send: path ref buffer underflow for key (%llu %u %llu)",
+						  found_key->objectid,
+						  found_key->type,
+						  found_key->offset);
+					ret = -EINVAL;
+					goto out;
+				}
 			}
 			p->start = start;
 		} else {
-- 
2.43.0