• Ryusuke Konishi's avatar
    nilfs2: fix potential memory overrun on inode · 957ed60b
    Ryusuke Konishi authored
    Each inode of nilfs2 stores a root node of a b-tree, and it turned out to
    have a memory overrun issue:
    
    Each b-tree node of nilfs2 stores a set of key-value pairs and the number
    of them (in "bn_nchildren" member of nilfs_btree_node struct), as well as
    a few other "bn_*" members.
    
    Since the value of "bn_nchildren" is used for operations on the key-values
    within the b-tree node, it can cause memory access overrun if a large
    number is incorrectly set to "bn_nchildren".
    
    For instance, nilfs_btree_node_lookup() function determines the range of
    binary search with it, and too large "bn_nchildren" leads
    nilfs_btree_node_get_key() in that function to overrun.
    
    As for intermediate b-tree nodes, this is prevented by a sanity check
    performed when each node is read from a drive, however, no sanity check
    has been done for root nodes stored in inodes.
    
    This patch fixes the issue by adding missing sanity check against b-tree
    root nodes so that it's called when on-memory inodes are read from ifile,
    inode metadata file.
    Signed-off-by: default avatarRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
    Cc: <stable@vger.kernel.org>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    957ed60b
btree.c 61 KB