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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2015-05-05 16:24:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-05-05 17:10:11 -0700
commitd8fd150fe3935e1692bf57c66691e17409ebb9c1 (patch)
treeb515748f38393aa4b3ff6f7562848e3242bf9739
parent05836c378c7af9527b98a83746f32c7289a5f3c8 (diff)
downloadlinux-d8fd150fe3935e1692bf57c66691e17409ebb9c1.tar.bz2
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 <konishi.ryusuke@lab.ntt.co.jp> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/nilfs2/btree.c2
-rw-r--r--include/linux/nilfs2_fs.h2
2 files changed, 2 insertions, 2 deletions
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