On Fri, 20 Feb 2015 13:58:42 -0800, Andrew Morton wrote: > On Fri, 20 Feb 2015 22:46:35 +0900 Ryusuke Konishi <konishi.ryusuke@xxxxxxxxxxxxx> wrote: > >> 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. > > How would one trigger this overrun? Mount an fs with a deliberately > corrupted/inconsistent fs image? Yes, this can be triggered by mounting an fs with a corrupted image deliberately or by chance. > Memory overrun sounds nasty so I'm thinking we add cc:stable to this > one. OK? Agreed. Ryusuke Konishi -- To unsubscribe from this list: send the line "unsubscribe linux-nilfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
