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 494372F94B1; Tue, 17 Jun 2025 16:13:40 +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=1750176820; cv=none; b=O6qm1RABYXRUb2iXnV/QG3pbxZsBQRaHkcVVu82J37zWHo/TVbU9IMmVUlWbg7OjyV/+BRjGqEF+mLHcJMSPoUyz8MO4sV9l7Sd5d2CsS6hilP8iMyP0WP9aJ5Di0aatQy/UAMLa6w9XPBJrksiMpslDd1tHEeV2nZrceZCr8WY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750176820; c=relaxed/simple; bh=QhS2aPYZjE/rY5nNuyvWQ4ytBcc2QUSnEpp/vHzmRfM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=mUwg9/7jrtvFd2vPGvoEvKD69xDBUuqFIxRiSgQh/LvLB0AMmCAlnUEnjwgDTiPerhv+j9EUNwKzXTVDts8aiFpckdZ+Juf/R02UkNN3MOfPRzEdM0VRdlC6GJiR2PCzyaxjCDdW2FYBCYfdQD8NziGfIJoiv6LvTfU7ggamjbQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=USTuqmVb; 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="USTuqmVb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5BF9C4CEE3; Tue, 17 Jun 2025 16:13:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1750176820; bh=QhS2aPYZjE/rY5nNuyvWQ4ytBcc2QUSnEpp/vHzmRfM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=USTuqmVbuNwqUtmXSc0WsaiRS3DmERbpi8k3I8+ATMLZdnBCKcWh+O1C+G6C8EK/D AHi/oaWZhUsmA0iRFmV4gE60Zl07Hrnf39QHOKSIiZn1SAsfNq67R6Nb8uF9XZ9hvq 4GwGaLQlJdP7fl7PXgm1yTN6OgUl8qccAh//T8No= 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 6.6 316/356] net: Fix TOCTOU issue in sk_is_readable() Date: Tue, 17 Jun 2025 17:27:11 +0200 Message-ID: <20250617152350.879757512@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250617152338.212798615@linuxfoundation.org> References: <20250617152338.212798615@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-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 dc625f94ee37b..e15bea43b2ecd 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -3043,8 +3043,11 @@ int sock_ioctl_inout(struct sock *sk, unsigned int cmd, int sk_ioctl(struct sock *sk, unsigned int cmd, void __user *arg); 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