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authorXi Wang <xi.wang@gmail.com>2012-11-11 11:20:01 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-11-26 12:14:18 -0800
commitdc61f8a222dd360e802205bbc908b175848aa5bf (patch)
treef075624653612246ba007df3eaead2b7b2500d4f
parent6ee34a305634346a23fce16352019d45097dc425 (diff)
ipv4: avoid undefined behavior in do_ip_setsockopt()
[ Upstream commit 0c9f79be295c99ac7e4b569ca493d75fdcc19e4e ] (1<<optname) is undefined behavior in C with a negative optname or optname larger than 31. In those cases the result of the shift is not necessarily zero (e.g., on x86). This patch simplifies the code with a switch statement on optname. It also allows the compiler to generate better code (e.g., using a 64-bit mask). Signed-off-by: Xi Wang <xi.wang@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/ipv4/ip_sockglue.c35
1 files changed, 22 insertions, 13 deletions
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 5eea4a811042..14bbfcf717ac 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -457,19 +457,28 @@ static int do_ip_setsockopt(struct sock *sk, int level,
struct inet_sock *inet = inet_sk(sk);
int val = 0, err;
- if (((1<<optname) & ((1<<IP_PKTINFO) | (1<<IP_RECVTTL) |
- (1<<IP_RECVOPTS) | (1<<IP_RECVTOS) |
- (1<<IP_RETOPTS) | (1<<IP_TOS) |
- (1<<IP_TTL) | (1<<IP_HDRINCL) |
- (1<<IP_MTU_DISCOVER) | (1<<IP_RECVERR) |
- (1<<IP_ROUTER_ALERT) | (1<<IP_FREEBIND) |
- (1<<IP_PASSSEC) | (1<<IP_TRANSPARENT) |
- (1<<IP_MINTTL) | (1<<IP_NODEFRAG))) ||
- optname == IP_UNICAST_IF ||
- optname == IP_MULTICAST_TTL ||
- optname == IP_MULTICAST_ALL ||
- optname == IP_MULTICAST_LOOP ||
- optname == IP_RECVORIGDSTADDR) {
+ switch (optname) {
+ case IP_PKTINFO:
+ case IP_RECVTTL:
+ case IP_RECVOPTS:
+ case IP_RECVTOS:
+ case IP_RETOPTS:
+ case IP_TOS:
+ case IP_TTL:
+ case IP_HDRINCL:
+ case IP_MTU_DISCOVER:
+ case IP_RECVERR:
+ case IP_ROUTER_ALERT:
+ case IP_FREEBIND:
+ case IP_PASSSEC:
+ case IP_TRANSPARENT:
+ case IP_MINTTL:
+ case IP_NODEFRAG:
+ case IP_UNICAST_IF:
+ case IP_MULTICAST_TTL:
+ case IP_MULTICAST_ALL:
+ case IP_MULTICAST_LOOP:
+ case IP_RECVORIGDSTADDR:
if (optlen >= sizeof(int)) {
if (get_user(val, (int __user *) optval))
return -EFAULT;