Messages in this thread Patch in this message | | | Date | Sat, 21 Feb 2015 10:13:28 +0900 (JST) | Subject | Re: [PATCH 1/1] nilfs2: fix potential memory overrun on inode | From | Ryusuke Konishi <> |
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On Sat, 21 Feb 2015 09:22:08 +0900 (JST), Ryusuke Konishi wrote: > 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@lab.ntt.co.jp> 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.
Could you apply the following amendment ?
I've got a warning from 0day kernel testing backend:
fs/nilfs2/btree.c: In function 'nilfs_btree_root_broken': >> fs/nilfs2/btree.c:394:3: warning: format '%lu' expects argument of type 'long unsigned int', but argument 2 has type 'ino_t' [-Wformat=] pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n", ^
This is output for s390 arch since ino_t doesn't mean "unsigned long" in s390.
Thanks, Ryusuke Konishi -- diff --git a/fs/nilfs2/btree.c b/fs/nilfs2/btree.c index c645d7c..ecdbae1 100644 --- a/fs/nilfs2/btree.c +++ b/fs/nilfs2/btree.c @@ -378,7 +378,7 @@ static int nilfs_btree_node_broken(const struct nilfs_btree_node *node, * Return Value: If node is broken, 1 is returned. Otherwise, 0 is returned. */ static int nilfs_btree_root_broken(const struct nilfs_btree_node *node, - ino_t ino) + unsigned long ino) { int level, flags, nchildren; int ret = 0; -- 1.8.3.1
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