xmit() functions should consume skb or return error codes in error
paths.
When the configuration "CONFIG_INET_ESPINTCP" is not used, the
implementation of the function "esp_output_tail_tcp" violates this rule.
The function frees the skb and returns the error code.
This change removes the kfree_skb from both functions, for both
esp4 and esp6.
This should not be reachable in the current code, so this change is just
a cleanup.
This bug was discovered and resolved using Coverity Static Analysis
Security Testing (SAST) by Synopsys, Inc.
Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
Signed-off-by: Hagar Hemdan <[email protected]>
---
net/ipv4/esp4.c | 3 +--
net/ipv6/esp6.c | 3 +--
2 files changed, 2 insertions(+), 4 deletions(-)
diff --git a/net/ipv4/esp4.c b/net/ipv4/esp4.c
index d33d12421814..e73de3abe37c 100644
--- a/net/ipv4/esp4.c
+++ b/net/ipv4/esp4.c
@@ -238,8 +238,7 @@ static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
#else
static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
{
- kfree_skb(skb);
-
+ WARN_ON(1);
return -EOPNOTSUPP;
}
#endif
diff --git a/net/ipv6/esp6.c b/net/ipv6/esp6.c
index 7371886d4f9f..600402e54ccd 100644
--- a/net/ipv6/esp6.c
+++ b/net/ipv6/esp6.c
@@ -255,8 +255,7 @@ static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
#else
static int esp_output_tail_tcp(struct xfrm_state *x, struct sk_buff *skb)
{
- kfree_skb(skb);
-
+ WARN_ON(1);
return -EOPNOTSUPP;
}
#endif
--
2.40.1
On Thu, May 16, 2024 at 08:03:09AM +0000, Hagar Hemdan wrote:
> xmit() functions should consume skb or return error codes in error
> paths.
> When the configuration "CONFIG_INET_ESPINTCP" is not used, the
> implementation of the function "esp_output_tail_tcp" violates this rule.
> The function frees the skb and returns the error code.
> This change removes the kfree_skb from both functions, for both
> esp4 and esp6.
>
> This should not be reachable in the current code, so this change is just
> a cleanup.
>
> This bug was discovered and resolved using Coverity Static Analysis
> Security Testing (SAST) by Synopsys, Inc.
>
> Fixes: e27cca96cd68 ("xfrm: add espintcp (RFC 8229)")
> Signed-off-by: Hagar Hemdan <[email protected]>
Hi Hagar,
If esp_output() may be the x->type->output callback called from esp_output()
then I agree that this seems to be a problem as it looks like a double free
may occur.
However, I believe that your proposed fix introduces will result in skb
being leaked leak in the case of esp_output_done() calling
esp_output_tail_tcp(). Perhaps a solution is for esp_output_done()
to free the skb if esp_output_tail_tcp() fails.
I did not analyse other call-chains, but I think such analysis is needed.
..