From d8fd150fe3935e1692bf57c66691e17409ebb9c1 Mon Sep 17 00:00:00 2001 From: Ryusuke Konishi Date: Tue, 5 May 2015 16:24:00 -0700 Subject: nilfs2: fix sanity check of btree level in nilfs_btree_root_broken() The range check for b-tree level parameter in nilfs_btree_root_broken() is wrong; it accepts the case of "level == NILFS_BTREE_LEVEL_MAX" even though the level is limited to values in the range of 0 to (NILFS_BTREE_LEVEL_MAX - 1). Since the level parameter is read from storage device and used to index nilfs_btree_path array whose element count is NILFS_BTREE_LEVEL_MAX, it can cause memory overrun during btree operations if the boundary value is set to the level parameter on device. This fixes the broken sanity check and adds a comment to clarify that the upper bound NILFS_BTREE_LEVEL_MAX is exclusive. Signed-off-by: Ryusuke Konishi Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/btree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/nilfs2') diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index 059f37137f9a..919fd5bb14a8 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -388,7 +388,7 @@ static int nilfs_btree_root_broken(const struct nilfs_btree_node *node, nchildren = nilfs_btree_node_get_nchildren(node); if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN || - level > NILFS_BTREE_LEVEL_MAX || + level >= NILFS_BTREE_LEVEL_MAX || nchildren < 0 || nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) { pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n", -- cgit v1.2.3