3.2-stable review patch. If anyone has any objections, please let me know.
------------------
From: Xi Wang <xi.w...@gmail.com>
[ 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.w...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
---
net/ipv4/ip_sockglue.c | 33 +++++++++++++++++++++------------
1 file changed, 21 insertions(+), 12 deletions(-)
diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c
index 09ff51b..0106d25 100644
--- a/net/ipv4/ip_sockglue.c
+++ b/net/ipv4/ip_sockglue.c
@@ -468,18 +468,27 @@ 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_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_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;
--
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