From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8B417222571; Mon, 23 Jun 2025 21:24:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750713842; cv=none; b=C48OOXaditXKr0d13Yw0ee+ID0NxrCF88ceeVnoZSZPf7hiH2QSKz9nrQ/Mhv0PjpTFbTG8gBf0x1hL2w87Qu4Hu3t8o0JFxuIM4W1IKb9+b9+2E64xbX5RKPJiag8EZDXRrXU2fxVvqmHZbjZu8xbpYstL7UXjCuwbSlLTCEIQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750713842; c=relaxed/simple; bh=UghdCmTu+Ne2QTDKV3sR7QW2FZcqlr9UktV0qVzJEso=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sTzlLQ2KIuy7fWBZLi1AHjBfAIDkFh/WRFYSepKidPHxMFNV0NGEFVE0AJ/fc6wgyrrLRgiZs04hZRXg2ylOEB76CbT9qdasajTRajlwR14cTdEFZZspZBc8kDU7BuTpIgvv+bfWE2JcqVH4RAdOEWwOyNXnkQD2KiUoMnZZQEc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xVRScM0Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xVRScM0Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23956C4CEED; Mon, 23 Jun 2025 21:24:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750713842; bh=UghdCmTu+Ne2QTDKV3sR7QW2FZcqlr9UktV0qVzJEso=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=xVRScM0YnVA2yq5JxWhV9/QBTbRtGRrjjC4ypua45oXQKZLOj0CiP0Ekd3CgiPrNk MAPMOcbYgH/4n0kJugrKNWaMQ6A7f4CVMvMfq1jJWgC8B7dALv4UXUf8R8M8KgsZu4 Ux+XdNg6T6tJGw4o3PvJs00UJTMCqe0FJaQM+s3A= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jakub Sitnicki , Michal Luczaj , Willem de Bruijn , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 152/411] net: Fix TOCTOU issue in sk_is_readable() Date: Mon, 23 Jun 2025 15:04:56 +0200 Message-ID: <20250623130637.457376343@linuxfoundation.org> X-Mailer: git-send-email 2.50.0 In-Reply-To: <20250623130632.993849527@linuxfoundation.org> References: <20250623130632.993849527@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Luczaj [ Upstream commit 2660a544fdc0940bba15f70508a46cf9a6491230 ] sk->sk_prot->sock_is_readable is a valid function pointer when sk resides in a sockmap. After the last sk_psock_put() (which usually happens when socket is removed from sockmap), sk->sk_prot gets restored and sk->sk_prot->sock_is_readable becomes NULL. This makes sk_is_readable() racy, if the value of sk->sk_prot is reloaded after the initial check. Which in turn may lead to a null pointer dereference. Ensure the function pointer does not turn NULL after the check. Fixes: 8934ce2fd081 ("bpf: sockmap redirect ingress support") Suggested-by: Jakub Sitnicki Signed-off-by: Michal Luczaj Reviewed-by: Willem de Bruijn Link: https://patch.msgid.link/20250609-skisreadable-toctou-v1-1-d0dfb2d62c37@rbox.co Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/sock.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/include/net/sock.h b/include/net/sock.h index 0461890f10ae7..fd68fd0adae7f 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2935,8 +2935,11 @@ int sock_bind_add(struct sock *sk, struct sockaddr *addr, int addr_len); static inline bool sk_is_readable(struct sock *sk) { - if (sk->sk_prot->sock_is_readable) - return sk->sk_prot->sock_is_readable(sk); + const struct proto *prot = READ_ONCE(sk->sk_prot); + + if (prot->sock_is_readable) + return prot->sock_is_readable(sk); + return false; } #endif /* _SOCK_H */ -- 2.39.5