From: Haogang Chen Date: Tue, 20 Dec 2011 01:11:56 +0000 (-0800) Subject: nilfs2: potential integer overflow in nilfs_ioctl_clean_segments() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=481fe17e973fb97aa3edf17c69557afe88d8334f;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.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 Signed-off-by: Ryusuke Konishi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index 3e654273cfc2..ac258beeda3c 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) {