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 436693F0A8C; Mon, 17 Aug 2026 14:17:58 +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=1786976279; cv=none; b=Aj5MmZImYgmWLUviINEn8uI0K1EadJ8j77MYuFHC4HKIEThqhzeCqbMeGAfXt0XhdbKuy0ezZ3Xchx7CZJV0NFmMvbgtx7px95jYzIN9Kfjvk/HG7PRLYepnDBJnVKdkHzd1YR39s7z+RC1WCf0fCJILcLeZNoOcDmClaRO0L7s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786976279; c=relaxed/simple; bh=kJZCXV7LTI8ThRxuZQaYiurbaPtwoRgLa/mM2xZrQJY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Hz3EWZEjvm9TCpJLfPuOsgz+cWRXqk3gSu7yWppdsI++YvTGGOo19USFwxIFrGmBTFv2OR9RBv/3n1EifCke2dRv8V/TbKKLjaD6dDmT4CXh+ewUJcz7vnRO073s1eQogm+RXpAX9enVJs3uDBvYlRGU1Ctw9jktAk7zbLn1Cgs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Xq69zsdf; 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="Xq69zsdf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A0B391F000E9; Mon, 17 Aug 2026 14:17:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786976278; bh=3+q0ScVR1lQjAn65uPLXo9X3CvYatLwhMf2pWdSOmyk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Xq69zsdfeHX0xMISyDDLFg0HJKBFeyRRtCc0Vxi/TjvM1/4V/sNzZQmhsfpiJOTvj NaSosN54o4OV1t10pBhr75XBwt0l58p9EYfyA5KJSUU1qwXCguGWXAtuAW16Lxx328 7NiDy5IvMG+LQiEeDeF5VkVpIraxkfZ0T6fizeHo= 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 5.10 316/389] net/smc: fix qentry overwrite for CONFIRM_LINK and ADD_LINK_CONT in smc_llc_event_handler() Date: Mon, 17 Aug 2026 15:32:35 +0200 Message-ID: <20260817132551.301927719@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132538.796021292@linuxfoundation.org> References: <20260817132538.796021292@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 5.10-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