[PATCH] check: check so offset is not bigger then the leaf

[Robert Marklund <robbelibobban@gmail.com>]

This could crash before because of dangerous dangling
offset of pointer.

Signed-off-by: Robert Marklund <robbelibobban@gmail.com>
---
 cmds-check.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/cmds-check.c b/cmds-check.c
index 778f141..da36758 100644
--- a/cmds-check.c
+++ b/cmds-check.c
@@ -8906,6 +8906,16 @@ static int build_roots_info_cache(struct btrfs_fs_info *info)
 			goto next;
 
 		ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
+
+		if ((long long)ei > info->extent_root->leafsize) {
+			 fprintf(stderr, "Bad leaf = %p, slot = %d\n", leaf, slot);
+			 fprintf(stderr, "item ptr = %p\n", ei);
+			 fprintf(stderr, "objectid = %llx\n", found_key.objectid);
+			 fprintf(stderr, "type     = %x\n", found_key.type);
+			 fprintf(stderr, "offset   = %llx\n", found_key.offset);
+			 goto next;
+		}
+
 		flags = btrfs_extent_flags(leaf, ei);
 
 		if (found_key.type == BTRFS_EXTENT_ITEM_KEY &&
-- 
2.1.0