Re: [PATCH net] sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

On Wed, 15 Apr 2026 23:19:03 -0400 you wrote:
> sctp_getsockopt_peer_auth_chunks() checks that the caller's optval
> buffer is large enough for the peer AUTH chunk list with
> 
>     if (len < num_chunks)
>             return -EINVAL;
> 
> but then writes num_chunks bytes to p->gauth_chunks, which lives
> at offset offsetof(struct sctp_authchunks, gauth_chunks) == 8
> inside optval.  The check is missing the sizeof(struct
> sctp_authchunks) = 8-byte header.  When the caller supplies
> len == num_chunks (for any num_chunks > 0) the test passes but
> copy_to_user() writes sizeof(struct sctp_authchunks) = 8 bytes
> past the declared buffer.
> 
> [...]

Here is the summary with links:
  - [net] sctp: fix OOB write to userspace in sctp_getsockopt_peer_auth_chunks
    https://git.kernel.org/netdev/net/c/0cf004ffb61c

You are awesome, thank you!
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