From patchwork Sun Feb 4 23:17:09 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13544875 X-Patchwork-Delegate: leon@leon.nu 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 46C19D26B; Sun, 4 Feb 2024 23:17:10 +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=1707088631; cv=none; b=Pd5F0HKvZCPr4rjB33joimsTQ/IufFaNohuUV+qoxvkBALl4Jj9KViCtqW0fdCTIUi+bnO/5AwTS3DWQTx9xYrsch8Hp33jXrVMa+qdx0AlCitBgR0Il40K9uiij89x5OfupMwhLhyuY+e0bU1AH7/a1Gnt2L+93/8PGS2NOQhc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707088631; c=relaxed/simple; bh=Q8M+ZV8AwjWJN106yxlomJOUg4m9WT4jLLZhalyAC+0=; h=Subject:From:To:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=qS3fo8VkAfzTmuVewQRxNM5ttm0vu2IL2XeXZVWh8n6s/ZaBUhrZTpHmRaf2gaczcIGLltj321TQssm+KxMqL1AWBif7D63CePKFvPY/dVccW3heFDWRmtgQc1q3VzEiIfe6nqD0+8p8KBg5Zq04TAPGj4bXsRHteBTSSgeT76U= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g6wD4lS3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g6wD4lS3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93E6FC433C7; Sun, 4 Feb 2024 23:17:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707088630; bh=Q8M+ZV8AwjWJN106yxlomJOUg4m9WT4jLLZhalyAC+0=; h=Subject:From:To:Date:In-Reply-To:References:From; b=g6wD4lS3OawgAmTkiVVgqp3YK9EZ7F9uFjWslDLr+F0qWeAdSaCex55PTBEzIlhj6 pYUAWpsMYDHZDx2nATKIb0NwlQg5LBjZDFZBrGk5jAGH1krKaAiLFfTKTTGjzVXxiC zZcg48CxitlgnzpstxhAbCvKds+0TQ2bQY5VKuJbE30hjTpmcy476n10pH8xQCuyxK AxYzkyxF5Oa5PF6Gdp0PY31OQIksMKpjQ4X/PKcgi7Msg78O5VBepFwrTaCKBrHnOw aSXbyFeAMOaUrmUXtZgXukqgahRjLdxLJAzaChVAc4HSdSM2EjA/rofe+gHFTXCE5m SSTrLIxI8kmSQ== Subject: [PATCH v2 06/12] svcrdma: Prevent a UAF in svc_rdma_send() From: Chuck Lever To: linux-nfs@vger.kernel.org, linux-rdma@vger.kernel.org Date: Sun, 04 Feb 2024 18:17:09 -0500 Message-ID: <170708862961.28128.4635466330893173032.stgit@bazille.1015granger.net> In-Reply-To: <170708844422.28128.2979813721958631192.stgit@bazille.1015granger.net> References: <170708844422.28128.2979813721958631192.stgit@bazille.1015granger.net> User-Agent: StGit/1.5 Precedence: bulk X-Mailing-List: linux-rdma@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Chuck Lever In some error flow cases, svc_rdma_wc_send() releases @ctxt. Copy the sc_cid field in @ctxt to a stack variable in order to guarantee that the value is available after the ib_post_send() call. In case the new comment looks a little strange, this will be done with at least one more field in a subsequent patch. Signed-off-by: Chuck Lever --- net/sunrpc/xprtrdma/svc_rdma_sendto.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/net/sunrpc/xprtrdma/svc_rdma_sendto.c b/net/sunrpc/xprtrdma/svc_rdma_sendto.c index f1f5c7b58fce..b6fc9299b472 100644 --- a/net/sunrpc/xprtrdma/svc_rdma_sendto.c +++ b/net/sunrpc/xprtrdma/svc_rdma_sendto.c @@ -316,12 +316,17 @@ static void svc_rdma_wc_send(struct ib_cq *cq, struct ib_wc *wc) * @rdma: transport on which to post the WR * @ctxt: send ctxt with a Send WR ready to post * + * Copy fields in @ctxt to stack variables in order to guarantee + * that these values remain available after the ib_post_send() call. + * In some error flow cases, svc_rdma_wc_send() releases @ctxt. + * * Returns zero if the Send WR was posted successfully. Otherwise, a * negative errno is returned. */ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt) { struct ib_send_wr *wr = &ctxt->sc_send_wr; + struct rpc_rdma_cid cid = ctxt->sc_cid; int ret; might_sleep(); @@ -337,12 +342,12 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt) if ((atomic_dec_return(&rdma->sc_sq_avail) < 0)) { svc_rdma_wake_send_waiters(rdma, 1); percpu_counter_inc(&svcrdma_stat_sq_starve); - trace_svcrdma_sq_full(rdma, &ctxt->sc_cid); + trace_svcrdma_sq_full(rdma, &cid); wait_event(rdma->sc_send_wait, atomic_read(&rdma->sc_sq_avail) > 0); if (test_bit(XPT_CLOSE, &rdma->sc_xprt.xpt_flags)) return -ENOTCONN; - trace_svcrdma_sq_retry(rdma, &ctxt->sc_cid); + trace_svcrdma_sq_retry(rdma, &cid); continue; } @@ -353,7 +358,7 @@ int svc_rdma_send(struct svcxprt_rdma *rdma, struct svc_rdma_send_ctxt *ctxt) return 0; } - trace_svcrdma_sq_post_err(rdma, &ctxt->sc_cid, ret); + trace_svcrdma_sq_post_err(rdma, &cid, ret); svc_xprt_deferred_close(&rdma->sc_xprt); svc_rdma_wake_send_waiters(rdma, 1); return ret;