[PATCH] nilfs2: avoid overflowing segment numbers in nilfs_ioctl_clean_segments()

[Xi Wang]

nsegs is read from userspace.  Limit its value and avoid overflowing
nsegs * sizeof(__u64) in the subsequent call to memdup_user().

This patch complements 481fe17e973fb97aa3edf17c69557afe88d8334f.

Signed-off-by: Xi Wang <xi.wang@xxxxxxxxx>
Cc: Haogang Chen <haogangchen@xxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
 fs/nilfs2/ioctl.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 8866496..2a70fce 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -603,6 +603,8 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 	nsegs = argv[4].v_nmembs;
 	if (argv[4].v_size != argsz[4])
 		goto out;
+	if (nsegs > UINT_MAX / sizeof(__u64))
+		goto out;
 
 	/*
 	 * argv[4] points to segment numbers this ioctl cleans.  We
-- 
1.7.5.4

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