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 9278E35FF5B for ; Wed, 23 Sep 2026 01:40:24 +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=1790127625; cv=none; b=hBU4NdeiTVSG4KXan6GfYjlGEghpWblkNKu7cS6HBxAdBdmPugNauJdm6RpmSB/kjExu4HLPFdcy8vnd+dQ81+6skcwTJMbnIZJevNmPV8FfkK18+MnJs2U6WjBNVOFm67sDb53PxYJrX5gZ97pJAtszV9yvMUu/rCGfP1MpOPI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790127625; c=relaxed/simple; bh=PxEBiu8phtJwI8vLKHLwbtiP3fFI9eC3wGz6sr5JWRU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oJWY0vQMaUbSqTdaj5JVkjexTQ5eOnX9RlNJwtaJo1vOnS3Hn8Od0Y9LVMJ+lWjZQ9M87ujGogTGWCr7JhSOIM56Ith1q2tudgJO7aMQclO9LRqeEH2DPkG6ralNB8WRbk/ustnCZ57APL3phIiZLMT/XFliMUDyAw3onAOzyEU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Wfmy7tno; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Wfmy7tno" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DFC5E1F000FF; Wed, 23 Sep 2026 01:40:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790127624; bh=bLVU7M9n749VT0uSJElHXdzt7ml83/5MVOCeE0vx2Wk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Wfmy7tno2dnamYj9/DAPDL6V5SKmyTuQQ7mP93U+X0gcU+XnYhZeSRkD/kte6K/xK gNdVeypRMJwB7zAT69w7NQREX1DI7cY0bSr2/uWkVyRVynGdpkjX42xb3ZE3dLrP8H Js8o08yisaB+wB3s5XrHzzK1n4fBZhGDPf9YphldL+DMk4Joh2DlGvYdVzTKdFExQG Vc5N9Ro9ye+3g1kijgdbU95ELh091m1I23LK3buscvkRa2MyK1uN+PZNg/HdU6macl JwmSlccV9cO7GAW6NlQmPant2p+IBnyCVmqttnx8LBdsrmx7AoTyYbfdNUSiZjiz5W y8/Upl8ZsW9KA== From: Sasha Levin To: stable@vger.kernel.org Cc: Frank Sorenson , David Howells , Paulo Alcantara , Sasha Levin Subject: [PATCH 5.10.y] smb: client: fix server->total_read for compound encrypted PDUs Date: Tue, 22 Sep 2026 21:40:22 -0400 Message-ID: <20260923014022.880433-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026092214-passage-deviant-ba7a@gregkh> References: <2026092214-passage-deviant-ba7a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Frank Sorenson [ Upstream commit f73726b83e4756fdaa099e1bc1143293bd57ad79 ] In receive_encrypted_standard(), server->total_read is left at the full decrypted frame size when walking sub-PDUs of a compound encrypted frame. As a result, cifs_handle_standard() passes this full size to smb2_check_message(), causing the PDU length guards to incorrectly validate the entire compound frame instead of the current sub-PDU. This allows truncated non-last sub-PDUs to bypass length validation, leading to out-of-bounds reads in smb2_get_data_area_len(). Fix this by setting server->total_read to the true length of the current sub-PDU: next_cmd for non-last sub-PDUs, and the remaining pdu_length for the last one. Fixes: b24df3e30cbf ("cifs: update receive_encrypted_standard to handle compounded responses") Cc: stable@vger.kernel.org Signed-off-by: Frank Sorenson Reviewed-by: David Howells Signed-off-by: Paulo Alcantara Signed-off-by: Sasha Levin --- fs/cifs/smb2ops.c | 1 + 1 file changed, 1 insertion(+) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 51f8ea0c89065..c9866251b5912 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -4972,6 +4972,7 @@ receive_encrypted_standard(struct TCP_Server_Info *server, one_more: shdr = (struct smb2_hdr *)buf; next_cmd = le32_to_cpu(shdr->NextCommand); + server->total_read = next_cmd ? next_cmd : pdu_length; if (*num_mids >= MAX_COMPOUND) { cifs_server_dbg(VFS, "too many PDUs in compound\n"); -- 2.53.0