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>
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@ -388,7 +388,7 @@ static int nilfs_btree_root_broken(const struct nilfs_btree_node *node,
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nchildren = nilfs_btree_node_get_nchildren(node);
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nchildren = nilfs_btree_node_get_nchildren(node);
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if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
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if (unlikely(level < NILFS_BTREE_LEVEL_NODE_MIN ||
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level > NILFS_BTREE_LEVEL_MAX ||
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level >= NILFS_BTREE_LEVEL_MAX ||
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nchildren < 0 ||
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nchildren < 0 ||
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nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
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nchildren > NILFS_BTREE_ROOT_NCHILDREN_MAX)) {
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pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n",
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pr_crit("NILFS: bad btree root (inode number=%lu): level = %d, flags = 0x%x, nchildren = %d\n",
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@ -460,7 +460,7 @@ struct nilfs_btree_node {
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/* level */
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/* level */
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#define NILFS_BTREE_LEVEL_DATA 0
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#define NILFS_BTREE_LEVEL_DATA 0
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#define NILFS_BTREE_LEVEL_NODE_MIN (NILFS_BTREE_LEVEL_DATA + 1)
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#define NILFS_BTREE_LEVEL_NODE_MIN (NILFS_BTREE_LEVEL_DATA + 1)
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#define NILFS_BTREE_LEVEL_MAX 14
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#define NILFS_BTREE_LEVEL_MAX 14 /* Max level (exclusive) */
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/**
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/**
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* struct nilfs_palloc_group_desc - block group descriptor
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* struct nilfs_palloc_group_desc - block group descriptor
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