2020-02-21 11:30:14

by Matteo Croce

Subject: [PATCH net] ipv4: ensure rcu_read_lock() in cipso_v4_error()

Similarly to commit c543cb4a5f07 ("ipv4: ensure rcu_read_lock() in
ipv4_link_failure()"), __ip_options_compile() must be called under rcu
protection.

Fixes: 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
Suggested-by: Guillaume Nault <[email protected]>
Signed-off-by: Matteo Croce <[email protected]>
---
net/ipv4/cipso_ipv4.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index 376882215919..0bd10a1f477f 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1724,6 +1724,7 @@ void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
{
unsigned char optbuf[sizeof(struct ip_options) + 40];
struct ip_options *opt = (struct ip_options *)optbuf;
+ int res;

if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
return;
@@ -1735,7 +1736,11 @@ void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)

memset(opt, 0, sizeof(struct ip_options));
opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
- if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
+ rcu_read_lock();
+ res = __ip_options_compile(dev_net(skb->dev), opt, skb, NULL);
+ rcu_read_unlock();
+
+ if (res)
return;

if (gateway)
--
2.24.1

2020-02-21 21:18:58

by Paul Moore

Subject: Re: [PATCH net] ipv4: ensure rcu_read_lock() in cipso_v4_error()

On Fri, Feb 21, 2020 at 6:28 AM Matteo Croce <[email protected]> wrote:
>
> Similarly to commit c543cb4a5f07 ("ipv4: ensure rcu_read_lock() in
> ipv4_link_failure()"), __ip_options_compile() must be called under rcu
> protection.
>
> Fixes: 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
> Suggested-by: Guillaume Nault <[email protected]>
> Signed-off-by: Matteo Croce <[email protected]>
> ---
> net/ipv4/cipso_ipv4.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)

This seems consistent with the ipv4_link_failure() fix, even though
ipv4_link_failure() has changed a bit since the fix.

Acked-by: Paul Moore <[email protected]>

> diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
> index 376882215919..0bd10a1f477f 100644
> --- a/net/ipv4/cipso_ipv4.c
> +++ b/net/ipv4/cipso_ipv4.c
> @@ -1724,6 +1724,7 @@ void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
> {
> unsigned char optbuf[sizeof(struct ip_options) + 40];
> struct ip_options *opt = (struct ip_options *)optbuf;
> + int res;
>
> if (ip_hdr(skb)->protocol == IPPROTO_ICMP || error != -EACCES)
> return;
> @@ -1735,7 +1736,11 @@ void cipso_v4_error(struct sk_buff *skb, int error, u32 gateway)
>
> memset(opt, 0, sizeof(struct ip_options));
> opt->optlen = ip_hdr(skb)->ihl*4 - sizeof(struct iphdr);
> - if (__ip_options_compile(dev_net(skb->dev), opt, skb, NULL))
> + rcu_read_lock();
> + res = __ip_options_compile(dev_net(skb->dev), opt, skb, NULL);
> + rcu_read_unlock();
> +
> + if (res)
> return;
>
> if (gateway)
> --
> 2.24.1

--
paul moore
http://www.paul-moore.com

2020-02-23 05:48:52

by David Miller

Subject: Re: [PATCH net] ipv4: ensure rcu_read_lock() in cipso_v4_error()

From: Matteo Croce <[email protected]>
Date: Fri, 21 Feb 2020 12:28:38 +0100

> Similarly to commit c543cb4a5f07 ("ipv4: ensure rcu_read_lock() in
> ipv4_link_failure()"), __ip_options_compile() must be called under rcu
> protection.
>
> Fixes: 3da1ed7ac398 ("net: avoid use IPCB in cipso_v4_error")
> Suggested-by: Guillaume Nault <[email protected]>
> Signed-off-by: Matteo Croce <[email protected]>

Applied and queued up for -stable, thanks.