From 3d777a64066f3b9db8a94834aaed6a9cf09808fd Mon Sep 17 00:00:00 2001 From: Haogang Chen Date: Fri, 16 Mar 2012 17:08:38 -0700 Subject: [PATCH] nilfs2: clamp ns_r_segments_percentage to [1, 99] ns_r_segments_percentage is read from the disk. Bogus or malicious value could cause integer overflow and malfunction due to meaningless disk usage calculation. This patch reports error when mounting such bogus volumes. Signed-off-by: Haogang Chen Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nilfs2/the_nilfs.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c index d32714094375b7..8a759016c2e3e0 100644 --- a/fs/nilfs2/the_nilfs.c +++ b/fs/nilfs2/the_nilfs.c @@ -409,6 +409,12 @@ static int nilfs_store_disk_layout(struct the_nilfs *nilfs, nilfs->ns_first_data_block = le64_to_cpu(sbp->s_first_data_block); nilfs->ns_r_segments_percentage = le32_to_cpu(sbp->s_r_segments_percentage); + if (nilfs->ns_r_segments_percentage < 1 || + nilfs->ns_r_segments_percentage > 99) { + printk(KERN_ERR "NILFS: invalid reserved segments percentage.\n"); + return -EINVAL; + } + nilfs_set_nsegments(nilfs, le64_to_cpu(sbp->s_nsegments)); nilfs->ns_crc_seed = le32_to_cpu(sbp->s_crc_seed); return 0;