Messages in this thread Patch in this message | | | From | Ryusuke Konishi <> | Subject | [PATCH 2/2] nilfs2: potential integer overflow in nilfs_ioctl_clean_segments() | Date | Wed, 14 Dec 2011 01:13:49 +0900 |
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From: Haogang Chen <haogangchen@gmail.com>
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> --- fs/nilfs2/ioctl.c | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index 3e65427..ac258be 100644 --- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -625,6 +625,9 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp, if (argv[n].v_nmembs > nsegs * nilfs->ns_blocks_per_segment) goto out_free; + if (argv[n].v_nmembs >= UINT_MAX / argv[n].v_size) + goto out_free; + len = argv[n].v_size * argv[n].v_nmembs; base = (void __user *)(unsigned long)argv[n].v_base; if (len == 0) { -- 1.7.7.4
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