From patchwork Wed Feb 28 22:44:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sabrina Dubroca X-Patchwork-Id: 13576026 X-Patchwork-Delegate: kuba@kernel.org Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [217.70.183.200]) (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 42CFA72901 for ; Wed, 28 Feb 2024 22:44:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.200 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709160264; cv=none; b=mPD0GqfSRAIGQWWp4jgzMqSyMqdKhe0p5qh50BHXi+z9YNNcUhZHQKLoYLPaxZdjNpx6tTpr/gvX7MYOa5DgplpGU3l59ONb2xP9ytLkYGYbp6cKS0o34kktSgrTMJtXQ9v4g9cNZOSoN+8FOlSAGaOMtwFDSp9kOKjJXpEA4pA= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709160264; c=relaxed/simple; bh=9ANgazVXWP2XssNvo+LtG4lvng3Sqtk5tBbhNztdISU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=dz7r6uWGdSJu6LcQdDHWPcopLerczqCF4mmnBiVn1BiomFtfJzN74If/5G3/fDMNdOQQoBSuC5jHReNtoTalAJeSfF6quHGPIVcIaIPfMEUlY4IS5aDF1z+zmWJnvOnw+8MD9L/f0ywut5tCZGNW2xm17NcJFSSF4pzOMgBqMFo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=queasysnail.net; spf=none smtp.mailfrom=queasysnail.net; arc=none smtp.client-ip=217.70.183.200 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=queasysnail.net Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=queasysnail.net Received: by mail.gandi.net (Postfix) with ESMTPSA id AA9A220003; Wed, 28 Feb 2024 22:44:13 +0000 (UTC) From: Sabrina Dubroca To: netdev@vger.kernel.org Cc: Sabrina Dubroca , Vakul Garg , Boris Pismenny , John Fastabend , Jakub Kicinski , "David S. Miller" , Eric Dumazet , Paolo Abeni , Simon Horman Subject: [PATCH net 4/4] tls: fix use-after-free on failed backlog decryption Date: Wed, 28 Feb 2024 23:44:00 +0100 Message-ID: <4755dd8d9bebdefaa19ce1439b833d6199d4364c.1709132643.git.sd@queasysnail.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-GND-Sasl: sd@queasysnail.net X-Patchwork-Delegate: kuba@kernel.org When the decrypt request goes to the backlog and crypto_aead_decrypt returns -EBUSY, tls_do_decryption will wait until all async decryptions have completed. If one of them fails, tls_do_decryption will return -EBADMSG and tls_decrypt_sg jumps to the error path, releasing all the pages. But the pages have been passed to the async callback, and have already been released by tls_decrypt_done. The only true async case is when crypto_aead_decrypt returns -EINPROGRESS. With -EBUSY, we already waited so we can tell tls_sw_recvmsg that the data is available for immediate copy, but we need to notify tls_decrypt_sg (via the new ->async_done flag) that the memory has already been released. Fixes: 859054147318 ("net: tls: handle backlogging of crypto requests") Signed-off-by: Sabrina Dubroca --- net/tls/tls_sw.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c index 1fd37fe13ffd..211f57164cb6 100644 --- a/net/tls/tls_sw.c +++ b/net/tls/tls_sw.c @@ -52,6 +52,7 @@ struct tls_decrypt_arg { struct_group(inargs, bool zc; bool async; + bool async_done; u8 tail; ); @@ -286,15 +287,18 @@ static int tls_do_decryption(struct sock *sk, } ret = crypto_aead_decrypt(aead_req); + if (ret == -EINPROGRESS) + return 0; + if (ret == -EBUSY) { ret = tls_decrypt_async_wait(ctx); - ret = ret ?: -EINPROGRESS; - } - if (ret == -EINPROGRESS) { - return 0; - } else if (darg->async) { - atomic_dec(&ctx->decrypt_pending); + darg->async_done = true; + /* all completions have run, we're not doing async anymore */ + darg->async = false; + return ret; } + + atomic_dec(&ctx->decrypt_pending); darg->async = false; return ret; @@ -1593,8 +1597,11 @@ static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov, /* Prepare and submit AEAD request */ err = tls_do_decryption(sk, sgin, sgout, dctx->iv, data_len + prot->tail_size, aead_req, darg); - if (err) + if (err) { + if (darg->async_done) + goto exit_free_skb; goto exit_free_pages; + } darg->skb = clear_skb ?: tls_strp_msg(ctx); clear_skb = NULL; @@ -1606,6 +1613,9 @@ static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov, return err; } + if (unlikely(darg->async_done)) + return 0; + if (prot->tail_size) darg->tail = dctx->tail;