2018-03-21 19:36:44

by Colin King

Subject: [PATCH][next] gre: fix TUNNEL_SEQ bit check on sequence numbering

From: Colin Ian King <[email protected]>

The current logic of flags | TUNNEL_SEQ is always non-zero and hence
sequence numbers are always incremented no matter the setting of the
TUNNEL_SEQ bit. Fix this by using & instead of |.

Detected by CoverityScan, CID#1466039 ("Operands don't affect result")

Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.")
Signed-off-by: Colin Ian King <[email protected]>
---
net/ipv4/ip_gre.c | 2 +-
net/ipv6/ip6_gre.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index 2fa2ef2e2af9..9ab1aa2f7660 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -550,7 +550,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
(TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
gre_build_header(skb, tunnel_hlen, flags, proto,
tunnel_id_to_key32(tun_info->key.tun_id),
- (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
+ (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);

df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index 0bcefc480aeb..3a98c694da5f 100644
--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c
@@ -725,7 +725,7 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
gre_build_header(skb, tunnel->tun_hlen,
flags, protocol,
tunnel_id_to_key32(tun_info->key.tun_id),
- (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
+ (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
: 0);

} else {
--
2.15.1

2018-03-21 21:25:11

by William Tu

Subject: Re: [PATCH][next] gre: fix TUNNEL_SEQ bit check on sequence numbering

On Wed, Mar 21, 2018 at 12:34 PM, Colin King <[email protected]> wrote:
> From: Colin Ian King <[email protected]>
>
> The current logic of flags | TUNNEL_SEQ is always non-zero and hence
> sequence numbers are always incremented no matter the setting of the
> TUNNEL_SEQ bit. Fix this by using & instead of |.
>
> Detected by CoverityScan, CID#1466039 ("Operands don't affect result")
>
> Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.")
> Signed-off-by: Colin Ian King <[email protected]>

Thanks for the fix!
btw, how can I access the CoverityScan result with this CID?

Acked-by: William Tu <[email protected]>


> ---
> net/ipv4/ip_gre.c | 2 +-
> net/ipv6/ip6_gre.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
> index 2fa2ef2e2af9..9ab1aa2f7660 100644
> --- a/net/ipv4/ip_gre.c
> +++ b/net/ipv4/ip_gre.c
> @@ -550,7 +550,7 @@ static void gre_fb_xmit(struct sk_buff *skb, struct net_device *dev,
> (TUNNEL_CSUM | TUNNEL_KEY | TUNNEL_SEQ);
> gre_build_header(skb, tunnel_hlen, flags, proto,
> tunnel_id_to_key32(tun_info->key.tun_id),
> - (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
> + (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++) : 0);
>
> df = key->tun_flags & TUNNEL_DONT_FRAGMENT ? htons(IP_DF) : 0;
>
> diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
> index 0bcefc480aeb..3a98c694da5f 100644
> --- a/net/ipv6/ip6_gre.c
> +++ b/net/ipv6/ip6_gre.c
> @@ -725,7 +725,7 @@ static netdev_tx_t __gre6_xmit(struct sk_buff *skb,
> gre_build_header(skb, tunnel->tun_hlen,
> flags, protocol,
> tunnel_id_to_key32(tun_info->key.tun_id),
> - (flags | TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
> + (flags & TUNNEL_SEQ) ? htonl(tunnel->o_seqno++)
> : 0);
>
> } else {
> --
> 2.15.1
>

2018-03-22 18:54:20

by David Miller

Subject: Re: [PATCH][next] gre: fix TUNNEL_SEQ bit check on sequence numbering

From: Colin King <[email protected]>
Date: Wed, 21 Mar 2018 19:34:58 +0000

> From: Colin Ian King <[email protected]>
>
> The current logic of flags | TUNNEL_SEQ is always non-zero and hence
> sequence numbers are always incremented no matter the setting of the
> TUNNEL_SEQ bit. Fix this by using & instead of |.
>
> Detected by CoverityScan, CID#1466039 ("Operands don't affect result")
>
> Fixes: 77a5196a804e ("gre: add sequence number for collect md mode.")
> Signed-off-by: Colin Ian King <[email protected]>

Applied, thanks Colin.