From d9bf5f130946695063469749bfd190087b7fad39 Mon Sep 17 00:00:00 2001 From: Weiping Pan Date: Tue, 13 Aug 2013 21:46:56 +0800 Subject: tun: compare with 0 instead of total_len Since we set "len = total_len" in the beginning of tun_get_user(), so we should compare the new len with 0, instead of total_len, or the if statement always returns false. Signed-off-by: Weiping Pan Signed-off-by: David S. Miller --- drivers/net/tun.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index db690a372260..5a8ee1cf090a 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1074,7 +1074,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash; if (!(tun->flags & TUN_NO_PI)) { - if ((len -= sizeof(pi)) > total_len) + if ((len -= sizeof(pi)) < 0) return -EINVAL; if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) @@ -1083,7 +1083,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } if (tun->flags & TUN_VNET_HDR) { - if ((len -= tun->vnet_hdr_sz) > total_len) + if ((len -= tun->vnet_hdr_sz) < 0) return -EINVAL; if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) -- cgit v1.2.3 From 15718ea0d844e4816dbd95d57a8a0e3e264ba90e Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Thu, 15 Aug 2013 15:52:57 +0300 Subject: tun: signedness bug in tun_get_user() The recent fix d9bf5f1309 "tun: compare with 0 instead of total_len" is not totally correct. Because "len" and "sizeof()" are size_t type, that means they are never less than zero. Signed-off-by: Dan Carpenter Acked-by: Michael S. Tsirkin Acked-by: Neil Horman Signed-off-by: David S. Miller --- drivers/net/tun.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'drivers/net/tun.c') diff --git a/drivers/net/tun.c b/drivers/net/tun.c index 5a8ee1cf090a..71af122edf2d 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1074,8 +1074,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, u32 rxhash; if (!(tun->flags & TUN_NO_PI)) { - if ((len -= sizeof(pi)) < 0) + if (len < sizeof(pi)) return -EINVAL; + len -= sizeof(pi); if (memcpy_fromiovecend((void *)&pi, iv, 0, sizeof(pi))) return -EFAULT; @@ -1083,8 +1084,9 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile, } if (tun->flags & TUN_VNET_HDR) { - if ((len -= tun->vnet_hdr_sz) < 0) + if (len < tun->vnet_hdr_sz) return -EINVAL; + len -= tun->vnet_hdr_sz; if (memcpy_fromiovecend((void *)&gso, iv, offset, sizeof(gso))) return -EFAULT; -- cgit v1.2.3