From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 764F23D301E; Mon, 17 Aug 2026 14:39:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977566; cv=none; b=Mr7Ib54KW/GjmiwfHahUg43ekbPGiX+RdDrWwXryp+nHaVK9E5IC434RwczIQGp5+rIaJVG9JoMRg+Bzh7AnS93U+/PB60VUouO/bG/552VP0V80cH6jrjSPh9MR0Dw6QkasFHmMD8uDB5EKLd+GrKwyP+7JnlbY6rHCmsrKmOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786977566; c=relaxed/simple; bh=tdYh15PQQ9GXMRgvDLMObYodRgSiEdb+LwUfQKzS5to=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LhS3hAL9qnQrRzLgEQLxYi44bt9p6vAGnS3NS3sMw5anwRh2aTDN7UrGklduTW8pZ2aoyH7ZmfwkLVJNDsKNPNLolYiPRhYOsozgRGJ3GreBJFewoOCMZSetlnloTIfdHnKz36H3gNPSZFTRwAq/A3KjFsa/MdnX3I6wgkqup/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=GtiSVovw; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="GtiSVovw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA34B1F000E9; Mon, 17 Aug 2026 14:39:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786977565; bh=7icMxTyOMw9abxFHhgKs/4BJYj9x/2+6Ao1QuYXWoZw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=GtiSVovwAhd88yIKq7CPZYNidK6LV7odb1/iPsyF9wEvrUgCHN5xlMDO/XZlbLgLi zqFexFY6lzhFkfhW3bF7Qg6Kj2pKZu15pkkmMfXnP/MBSFmMfTQew6L4iaHmxqr7xl FiqcOXk9QhETjgW4laVoUW2iZ2dHVkV1A8Tvi3pM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mahanta Jambigi , Hidayath Khan , Sidraya Jayagond , Dust Li , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 373/456] net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler() Date: Mon, 17 Aug 2026 15:32:43 +0200 Message-ID: <20260817132554.077526355@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132539.792407575@linuxfoundation.org> References: <20260817132539.792407575@linuxfoundation.org> User-Agent: quilt/0.69 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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mahanta Jambigi [ Upstream commit 976245094925bab9bc39366b2e9ab44ffcde61d0 ] The SMC_LLC_CONFIRM_LINK / SMC_LLC_ADD_LINK_CONT branch in smc_llc_event_handler() stores an incoming qentry into the local LLC flow without first checking whether a qentry is already pending. If a malicious or buggy peer sends a second CONFIRM_LINK or ADD_LINK_CONT request while a flow is active and flow->qentry is already set, smc_llc_flow_qentry_set() overwrites the pointer without freeing the previous allocation, leaking one kmalloc-96 object per spurious message. The sibling SMC_LLC_DELETE_LINK branch already has the correct !flow->qentry guard. Apply the same guard to the CONFIRM_LINK/ADD_LINK_CONT branch so that a duplicate message when qentry is already occupied falls through to break and is freed by the kfree(qentry) at the out: label, rather than silently leaking the existing allocation. The response direction (smc_llc_rx_response()) is unaffected: it already guards with flow->qentry at the equivalent site and drops duplicate responses correctly. Fixes: 0fb0b02bd6fd ("net/smc: adapt SMC client code to use the LLC flow") Signed-off-by: Mahanta Jambigi Reviewed-by: Hidayath Khan Reviewed-by: Sidraya Jayagond Reviewed-by: Dust Li Link: https://patch.msgid.link/20260729130153.970800-1-mjambigi@linux.ibm.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/smc/smc_llc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/smc/smc_llc.c b/net/smc/smc_llc.c index d5ee961ca72d5..572d02bfd3eda 100644 --- a/net/smc/smc_llc.c +++ b/net/smc/smc_llc.c @@ -1582,7 +1582,8 @@ static void smc_llc_event_handler(struct smc_llc_qentry *qentry) return; case SMC_LLC_CONFIRM_LINK: case SMC_LLC_ADD_LINK_CONT: - if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE) { + if (lgr->llc_flow_lcl.type != SMC_LLC_FLOW_NONE && + !lgr->llc_flow_lcl.qentry) { /* a flow is waiting for this message */ smc_llc_flow_qentry_set(&lgr->llc_flow_lcl, qentry); wake_up(&lgr->llc_msg_waiter); -- 2.53.0