From: Ryusuke Konishi Date: Tue, 5 May 2015 23:24:00 +0000 (-0700) Subject: nilfs2: fix sanity check of btree level in nilfs_btree_root_broken() X-Git-Tag: firefly_0821_release~176^2~1819^2~2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d8fd150fe3935e1692bf57c66691e17409ebb9c1;p=firefly-linux-kernel-4.4.55.git 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 --- 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", diff --git a/include/linux/nilfs2_fs.h b/include/linux/nilfs2_fs.h index ff3fea3194c6..9abb763e4b86 100644 --- a/include/linux/nilfs2_fs.h +++ b/include/linux/nilfs2_fs.h @@ -460,7 +460,7 @@ struct nilfs_btree_node { /* level */ #define NILFS_BTREE_LEVEL_DATA 0 #define NILFS_BTREE_LEVEL_NODE_MIN (NILFS_BTREE_LEVEL_DATA + 1) -#define NILFS_BTREE_LEVEL_MAX 14 +#define NILFS_BTREE_LEVEL_MAX 14 /* Max level (exclusive) */ /** * struct nilfs_palloc_group_desc - block group descriptor