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 1045337CD3E for ; Sat, 15 Aug 2026 06:29:38 +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=1786775379; cv=none; b=dgY3yx3wFohq2Z7qtqqeW0rfxpMsQFKapgucJ1YfIc39dYt2rRWQEKhPwGrhZhvs6biBNtZ8sZ8uIbTSDneVf/VXbKeQfilVOhnj8eprkN3j2jbwCE02jxIeYaVImCcmjrel47uypbSJeigVFEFLom+YEyBR0CC0ITkFLsaSDFs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786775379; c=relaxed/simple; bh=y/+NZKjKo6UrpIEZrYZm7VW2MqeW+FuO2Ib5ZZ8iKqg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=lVbniO0VjUhk6QYvaFWllN2JFNQV8rZ12H+C9toRTHUhNLU+iWwdRSWR2Fdtzi/NGdkWsGE59VT8XDiL7pUza3gYrYjk/b7Uqt22gDYu+dJAeAikMtd6lt3ImgXSgiRPT1rkbdvNXiWhHozvgAVQAyp65wBmh15ONBuqzGYhlJg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=aOKRppEv; 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="aOKRppEv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 643CD1F000E9; Sat, 15 Aug 2026 06:29:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786775378; bh=1JcP5j/biuSzf1qTH8KsOYwdKDE+lBnEZ08UcGcD1Sw=; h=From:To:Cc:Subject:Date:Reply-To; b=aOKRppEvaG/YyP9tup+bgLm8BS84I4LUhBHo36FDlqMxWbr/CDTAXsCGfkUdElpeS IRFlkkflIBFVN2D0rssFhUb+qJQQvwskz6gY96s83rFcBrSOKktnFh77JJ896f70Un fx4HSLzl5PImY/Xu+2nCAYg24lM2WdsIBIiVJGl8= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-72466: xprtrdma: Fix bcall rep leak and unbounded peek Date: Sat, 15 Aug 2026 15:09:05 +0900 Message-ID: <2026081534-CVE-2026-72466-3fcf@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4997; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=6CoKv3/dm9CzyJdMpl52EDYyLwd7N+dWpP142nZUyh0=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNDL/Ksn3aV9yQOucttXVrW0/Syidp52KVr6q4f3p0i bnF6+OGjlgWBkEmBlkxRZYv23iO7q84pOhlaHsaZg4rE8gQBi5OAZjIBDWG+VViE+QN0re5Vj8I uigXdkDFVUZ7CcOC6RpKApKr1+wND4+McQv5saj0ocd1AA== X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Fix bcall rep leak and unbounded peek rpcrdma_is_bcall() decodes a reply's first words to decide whether the frame is a backchannel call. Two issues in that decode path let a short or malformed reply leak the receive buffer and drain the Receive queue. First, the speculative peek p = xdr_inline_decode(xdr, 0); /* five p++ reads follow */ asks xdr_inline_decode() for zero bytes, which returns xdr->p without consulting xdr->end. The five subsequent __be32 reads can then walk up to 20 bytes past the wire payload into stale regbuf contents and misclassify the reply as a backchannel call. Second, after the post-peek p = xdr_inline_decode(xdr, 3 * sizeof(*p)); if (unlikely(!p)) return true; the short-header arm returns true without calling rpcrdma_bc_receive_call(). The contract with the caller is that a true return transfers ownership of rep to the backchannel path: rpcrdma_reply_handler() if (rpcrdma_is_bcall(r_xprt, rep)) return; /* bare return, skips out_post */ ... out_post: rpcrdma_post_recvs(r_xprt, credits + ...); Because rpcrdma_bc_receive_call() never ran, no one took rep, but rpcrdma_reply_handler still bare-returns past rpcrdma_rep_put() and rpcrdma_post_recvs(). The rep, with its persistently DMA-mapped receive buffer, is orphaned on rb_all_reps and freed only at transport teardown. This completion reposts nothing, so its slot is reclaimed only when a later forward-channel reply reaches out_post and rpcrdma_post_recvs() allocates a fresh rep to backfill; absent that traffic the Receive queue drains and the peer's Sends draw RNR NAKs. Fix by consulting xdr->end after the zero-length peek so the five __be32 reads cannot run unless 20 bytes of wire payload remain. A byte-precise comparison against xdr->end is required because a non-4-aligned receive rounds the stream's word count up past the true payload. Also return false from the short-header arm so the reply falls through the normal out_norqst cleanup chain (rpcrdma_rep_put() plus rpcrdma_post_recvs()). The Linux kernel CVE team has assigned CVE-2026-72466 to this issue. Affected and fixed versions =========================== Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 5.15.212 with commit 0cee8f9c3b14bd6dee9c4310090a7f45b89b834f Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 6.1.178 with commit 7afc2f8d2fd9394724df9eaf22ce7a71029a5fba Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 6.6.145 with commit 88b5346284a184a6b7d019912232a571d672d3e3 Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 6.12.97 with commit 07aa506436be7634e381e1e1f6d0efa9efc81ecc Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 6.18.40 with commit d7a2870dde3bb09d51d6b9c877642996ad6b92dd Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 7.1.5 with commit 118a16a18c59f7ad8084b2d13988839b669fca10 Issue introduced in 4.14 with commit 41c8f70f5a3db7e06179186b6525fd9ee1d7d314 and fixed in 7.2-rc1 with commit c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-72466 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: net/sunrpc/xprtrdma/rpc_rdma.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/0cee8f9c3b14bd6dee9c4310090a7f45b89b834f https://git.kernel.org/stable/c/7afc2f8d2fd9394724df9eaf22ce7a71029a5fba https://git.kernel.org/stable/c/88b5346284a184a6b7d019912232a571d672d3e3 https://git.kernel.org/stable/c/07aa506436be7634e381e1e1f6d0efa9efc81ecc https://git.kernel.org/stable/c/d7a2870dde3bb09d51d6b9c877642996ad6b92dd https://git.kernel.org/stable/c/118a16a18c59f7ad8084b2d13988839b669fca10 https://git.kernel.org/stable/c/c7653d5cebc8492c77ec0415b5e9c0fb3e644bc6