[1/2] Revert "net: af_key: add check for pfkey_broadcast in function pfkey_process"

Commit Message

Steffen Klassert June 1, 2022, 10:33 a.m. UTC

From: Michal Kubecek <[e-mail]>

This reverts commit 4dc2a5a8f6754492180741facf2a8787f2c415d7.

A non-zero return value from pfkey_broadcast() does not necessarily mean
an error occurred as this function returns -ESRCH when no registered
listener received the message. In particular, a call with
BROADCAST_PROMISC_ONLY flag and null one_sk argument can never return
zero so that this commit in fact prevents processing any PF_KEY message.
One visible effect is that racoon daemon fails to find encryption
algorithms like aes and refuses to start.

Excluding -ESRCH return value would fix this but it's not obvious that
we really want to bail out here and most other callers of
pfkey_broadcast() also ignore the return value. Also, as pointed out by
Steffen Klassert, PF_KEY is kind of deprecated and newer userspace code
should use netlink instead so that we should only disturb the code for
really important fixes.

v2: add a comment explaining why is the return value ignored

Signed-off-by: Michal Kubecek <[e-mail]>
Signed-off-by: Steffen Klassert <[e-mail]>
---
 net/key/af_key.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

[e-mail] June 2, 2022, 12:50 a.m. UTC | #1

Hello:

This series was applied to netdev/net.git (master)
by Steffen Klassert <[e-mail]>:

On Wed, 1 Jun 2022 12:33:48 +0200 you wrote:
> From: Michal Kubecek <[e-mail]>
> 
> This reverts commit 4dc2a5a8f6754492180741facf2a8787f2c415d7.
> 
> A non-zero return value from pfkey_broadcast() does not necessarily mean
> an error occurred as this function returns -ESRCH when no registered
> listener received the message. In particular, a call with
> BROADCAST_PROMISC_ONLY flag and null one_sk argument can never return
> zero so that this commit in fact prevents processing any PF_KEY message.
> One visible effect is that racoon daemon fails to find encryption
> algorithms like aes and refuses to start.
> 
> [...]

Here is the summary with links:
  - [1/2] Revert "net: af_key: add check for pfkey_broadcast in function pfkey_process"
    https://git.kernel.org/netdev/net/c/9c90c9b3e50e
  - [2/2] xfrm: do not set IPv4 DF flag when encapsulating IPv6 frames <= 1280 bytes.
    https://git.kernel.org/netdev/net/c/6821ad877034

You are awesome, thank you!

Patch

diff --git a/net/key/af_key.c b/net/key/af_key.c
index 339d95df19d3..d93bde657359 100644
--- a/net/key/af_key.c
+++ b/net/key/af_key.c
@@ -2826,10 +2826,12 @@  static int pfkey_process(struct sock *sk, struct sk_buff *skb, const struct sadb
 	void *ext_hdrs[SADB_EXT_MAX];
 	int err;
 
-	err = pfkey_broadcast(skb_clone(skb, GFP_KERNEL), GFP_KERNEL,
-			      BROADCAST_PROMISC_ONLY, NULL, sock_net(sk));
-	if (err)
-		return err;
+	/* Non-zero return value of pfkey_broadcast() does not always signal
+	 * an error and even on an actual error we may still want to process
+	 * the message so rather ignore the return value.
+	 */
+	pfkey_broadcast(skb_clone(skb, GFP_KERNEL), GFP_KERNEL,
+			BROADCAST_PROMISC_ONLY, NULL, sock_net(sk));
 
 	memset(ext_hdrs, 0, sizeof(ext_hdrs));
 	err = parse_exthdrs(skb, hdr, ext_hdrs);