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 908C0248BA1; Wed, 15 Jan 2025 10:50:33 +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=1736938233; cv=none; b=jtATpkAU5pDADKTW2ll+Lb3SRAts/HafGhz2vFxKBw6zpLO6TYT6bKEh1Yn5SodkfAmi/TtcHa2TKA/dBhUN1v7VfuhhONfHsubkA9MZMOuAiWo7ZZ5lKfEQZHI3p1E1/lDImAkKAXrHgNyzGZ6ADGVCtERunGLCX7QoW4QU/H4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736938233; c=relaxed/simple; bh=bARCnv5+psoDtvNkjlflY6CitRatzkpQi1KOAKB9EKw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lWmFh1G45saWVSkQgtfjJBUDexOa/6WoEkfmXv7am0x/tsVGbL5i90kkzdhwp0BwMIXuqeuikIP3yRpDsdEwHUaNDEqmFhDdHpi8AyObutCnCKzS7wag4yCVB+pwPWCd1YqhOcdrppu3/eJOupXOiYldpU23UDwkKZ9x9kCqNp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YCi8lfP4; 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="YCi8lfP4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F317CC4CEDF; Wed, 15 Jan 2025 10:50:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1736938233; bh=bARCnv5+psoDtvNkjlflY6CitRatzkpQi1KOAKB9EKw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=YCi8lfP4XX9pd4HZikU4gx1UmdcO/ziO2gG4M2nZgaftaOqQxdmWorD5aoefwTa90 lmdLYd0BlyzaqRrSch/okFuIL4cFuz3Yyr+OHrWRT7Y0+Npmd9G4kHQlyvsIIGOHt8 MjWZdUdh3VM2tut1XrvLrf5aldPbYOYn9ydRX6Y0= 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 6.12 095/189] sctp: sysctl: cookie_hmac_alg: avoid using current->nsproxy Date: Wed, 15 Jan 2025 11:36:31 +0100 Message-ID: <20250115103610.116274707@linuxfoundation.org> X-Mailer: git-send-email 2.48.0 In-Reply-To: <20250115103606.357764746@linuxfoundation.org> References: <20250115103606.357764746@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 6.12-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 @@ -387,7 +387,8 @@ static struct ctl_table sctp_net_table[] static int proc_sctp_do_hmac_alg(const struct ctl_table *ctl, int write, void *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; bool changed = false; char *none = "none";