From: Haogang Chen <haogangchen@gmail.com>
Date: Tue, 20 Dec 2011 01:11:56 +0000 (-0800)
Subject: nilfs2: potential integer overflow in nilfs_ioctl_clean_segments()
X-Git-Tag: v3.2-rc7~36
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=481fe17e973fb97aa3edf17c69557afe88d8334f;p=pandora-kernel.git

nilfs2: potential integer overflow in nilfs_ioctl_clean_segments()

There is a potential integer overflow in nilfs_ioctl_clean_segments().
When a large argv[n].v_nmembs is passed from the userspace, the subsequent
call to vmalloc() will allocate a buffer smaller than expected, which
leads to out-of-bound access in nilfs_ioctl_move_blocks() and
lfs_clean_segments().

The following check does not prevent the overflow because nsegs is also
controlled by the userspace and could be very large.

		if (argv[n].v_nmembs > nsegs * nilfs->ns_blocks_per_segment)
			goto out_free;

This patch clamps argv[n].v_nmembs to UINT_MAX / argv[n].v_size, and
returns -EINVAL when overflow.

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>
---

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