* [PATCH net-next] net: warn if mac header was not set
@ 2022-06-20 9:30 Eric Dumazet
2022-06-21 9:21 ` Paolo Abeni
2022-06-21 9:40 ` patchwork-bot+netdevbpf
0 siblings, 2 replies; 3+ messages in thread
From: Eric Dumazet @ 2022-06-20 9:30 UTC (permalink / raw)
To: David S . Miller, Jakub Kicinski, Paolo Abeni
Cc: netdev, Eric Dumazet, Eric Dumazet
From: Eric Dumazet <edumazet@google.com>
Make sure skb_mac_header(), skb_mac_offset() and skb_mac_header_len() uses
are not fooled if the mac header has not been set.
These checks are enabled if CONFIG_DEBUG_NET=y
This commit will likely expose existing bugs in linux networking stacks.
Signed-off-by: Eric Dumazet <edumazet@google.com>
---
include/linux/skbuff.h | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 82edf0359ab32d0d7cd583676b38d569ce0b24cc..cd4a8268894acce4bde16dc0fedb7eb13706f515 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2763,8 +2763,14 @@ static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
skb->network_header += offset;
}
+static inline int skb_mac_header_was_set(const struct sk_buff *skb)
+{
+ return skb->mac_header != (typeof(skb->mac_header))~0U;
+}
+
static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
{
+ DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
return skb->head + skb->mac_header;
}
@@ -2775,14 +2781,10 @@ static inline int skb_mac_offset(const struct sk_buff *skb)
static inline u32 skb_mac_header_len(const struct sk_buff *skb)
{
+ DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
return skb->network_header - skb->mac_header;
}
-static inline int skb_mac_header_was_set(const struct sk_buff *skb)
-{
- return skb->mac_header != (typeof(skb->mac_header))~0U;
-}
-
static inline void skb_unset_mac_header(struct sk_buff *skb)
{
skb->mac_header = (typeof(skb->mac_header))~0U;
--
2.36.1.476.g0c4daa206d-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: warn if mac header was not set
2022-06-20 9:30 [PATCH net-next] net: warn if mac header was not set Eric Dumazet
@ 2022-06-21 9:21 ` Paolo Abeni
2022-06-21 9:40 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: Paolo Abeni @ 2022-06-21 9:21 UTC (permalink / raw)
To: Eric Dumazet, David S . Miller, Jakub Kicinski; +Cc: netdev, Eric Dumazet
Hello,
On Mon, 2022-06-20 at 02:30 -0700, Eric Dumazet wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Make sure skb_mac_header(), skb_mac_offset() and skb_mac_header_len() uses
> are not fooled if the mac header has not been set.
>
> These checks are enabled if CONFIG_DEBUG_NET=y
>
> This commit will likely expose existing bugs in linux networking stacks.
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
> include/linux/skbuff.h | 12 +++++++-----
> 1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
> index 82edf0359ab32d0d7cd583676b38d569ce0b24cc..cd4a8268894acce4bde16dc0fedb7eb13706f515 100644
> --- a/include/linux/skbuff.h
> +++ b/include/linux/skbuff.h
> @@ -2763,8 +2763,14 @@ static inline void skb_set_network_header(struct sk_buff *skb, const int offset)
> skb->network_header += offset;
> }
>
> +static inline int skb_mac_header_was_set(const struct sk_buff *skb)
> +{
> + return skb->mac_header != (typeof(skb->mac_header))~0U;
> +}
> +
> static inline unsigned char *skb_mac_header(const struct sk_buff *skb)
> {
> + DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
> return skb->head + skb->mac_header;
> }
>
> @@ -2775,14 +2781,10 @@ static inline int skb_mac_offset(const struct sk_buff *skb)
>
> static inline u32 skb_mac_header_len(const struct sk_buff *skb)
> {
> + DEBUG_NET_WARN_ON_ONCE(!skb_mac_header_was_set(skb));
The patch LGTM.
I'm wondering if it's worthy adding similar debug checks for network
and transport offset (with more patches). e.g. still in
skb_mac_header_len():
DEBUG_NET_WARN_ON_ONCE(skb->network_header < skb->mac_header);
Thanks!
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: warn if mac header was not set
2022-06-20 9:30 [PATCH net-next] net: warn if mac header was not set Eric Dumazet
2022-06-21 9:21 ` Paolo Abeni
@ 2022-06-21 9:40 ` patchwork-bot+netdevbpf
1 sibling, 0 replies; 3+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-06-21 9:40 UTC (permalink / raw)
To: Eric Dumazet; +Cc: davem, kuba, pabeni, netdev, edumazet
Hello:
This patch was applied to netdev/net-next.git (master)
by Paolo Abeni <pabeni@redhat.com>:
On Mon, 20 Jun 2022 02:30:17 -0700 you wrote:
> From: Eric Dumazet <edumazet@google.com>
>
> Make sure skb_mac_header(), skb_mac_offset() and skb_mac_header_len() uses
> are not fooled if the mac header has not been set.
>
> These checks are enabled if CONFIG_DEBUG_NET=y
>
> [...]
Here is the summary with links:
- [net-next] net: warn if mac header was not set
https://git.kernel.org/netdev/net-next/c/f9aefd6b2aa3
You are awesome, thank you!
--
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-06-20 9:30 [PATCH net-next] net: warn if mac header was not set Eric Dumazet
2022-06-21 9:21 ` Paolo Abeni
2022-06-21 9:40 ` patchwork-bot+netdevbpf
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