From 3d777a64066f3b9db8a94834aaed6a9cf09808fd Mon Sep 17 00:00:00 2001
From: Haogang Chen <haogangchen@gmail.com>
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 <haogangchen@gmail.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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 d32714094375..8a759016c2e3 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;
--
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