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 12225383; Thu, 30 Jan 2025 14:17:57 +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=1738246677; cv=none; b=SBksaarknDNq3k3L6Z1c4Ab5CUO3QZ66Wp2TGmmiSxw+yhtLdNBAfoGH/FvKX6KyETI6Ol33afsCLDzxBxV00xrPVJ17wV+/Fymd2gufQjg9s1OUmI3afN8+LY/WZVsDkBhHKKjq9SqirVF7+tDJcaw2ZdI6qgKmgg+Jo3CiYII= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738246677; c=relaxed/simple; bh=0T5cce5KXv3vZ8Ji2tmU2VOHbTrjtX3+zwD01aJNUQY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eaxcCM40jCK+g9rw5H/Pka+7iUsTbA1qm2gX5NrutKZpvD+6tS3yA3DuwQAeFap3m+ZvYIjPJ7N7G6DUWw6IlMa8HMyi2cFk11WD0i+mFyxlVb4KGIWqdIg4NYZD81RpN7am2taT3yWzCtxDYXCTbWwk2E/rWAfva7zMBuVy+KI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=m6KrtcPB; 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="m6KrtcPB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82412C4CED2; Thu, 30 Jan 2025 14:17:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738246676; bh=0T5cce5KXv3vZ8Ji2tmU2VOHbTrjtX3+zwD01aJNUQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m6KrtcPBSE1JXi38mNghArKfwqVM1KqUndblpffKjW3RsDVvLYfbPnm5qMIU/fiIm CHpYIQFidNlSpFl+UaHp6gBytJnXUdAIeXWcvET3DH/nMQLbmQvXA+wiJHPkJndQSM RXQ6okbIhvgZFAwghhlXswgfFodunsQlqF6gwfu4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Al Viro , "Matthieu Baerts (NGI0)" , Jakub Kicinski Subject: [PATCH 5.4 12/91] sctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy Date: Thu, 30 Jan 2025 15:00:31 +0100 Message-ID: <20250130140134.158737548@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250130140133.662535583@linuxfoundation.org> References: <20250130140133.662535583@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 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Matthieu Baerts (NGI0) commit ea62dd1383913b5999f3d16ae99d411f41b528d4 upstream. As mentioned in a previous commit of this series, using the 'net' structure via 'current' is not recommended for different reasons: - Inconsistency: getting info from the reader's/writer's netns vs only from the opener's netns. - current->nsproxy can be NULL in some cases, resulting in an 'Oops' (null-ptr-deref), e.g. when the current task is exiting, as spotted by syzbot [1] using acct(2). The 'net' structure can be obtained from the table->data using container_of(). Note that table->data could also be used directly, as this is the only member needed from the 'net' structure, but that would increase the size of this fix, to use '*data' everywhere 'net->sctp.sctp_hmac_alg' is used. Fixes: 3c68198e7511 ("sctp: Make hmac algorithm selection for cookie generation dynamic") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/67769ecb.050a0220.3a8527.003f.GAE@google.com [1] Suggested-by: Al Viro Signed-off-by: Matthieu Baerts (NGI0) Link: https://patch.msgid.link/20250108-net-sysctl-current-nsproxy-v1-4-5df34b2083e8@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sctp/sysctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/sctp/sysctl.c +++ b/net/sctp/sysctl.c @@ -441,7 +441,8 @@ static int proc_sctp_do_auth(struct ctl_ void __user *buffer, size_t *lenp, loff_t *ppos) { - struct net *net = current->nsproxy->net_ns; + struct net *net = container_of(ctl->data, struct net, + sctp.sctp_hmac_alg); struct ctl_table tbl; int new_value, ret;