From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793672541; b=N82aFyh4RI1PGrTnhyimbXw40hPTy7MpMeyve0S5QrR5ql3DGzulMDhAJfN59Pz4Q7HG lOr4Jmgg7AuLJJFuVl6t2ZhPMVzyzZE/AjQnXSWjZx7WcD4kPU6uf7tSo7jTIx7w4j9ZK aiey6d3w/U7X6mgZKUbQZW5UPFlWN6i9AKf3rbfBhvWSO5+87hehiz8T97fk79j6nOmWQ aDcA0kmQNSGoDQ/8NiDKaAaKHE/YjN9zHlKmDk+wMnKoozhYbpyToQ23opYcoltQSMuJ1 g/3C5uZIfhb2oueOLJpevJKmAQdKRv83xk2Pph3DI+n6X4i7hlPw7Bcs570j0zxWfqg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793672541; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=b2YL294FU9QpZFiKRZDyCeHsQ5/dyMnUVgRpiRhxEPM=; b=dd33Q3KERqqnM3HmT+uahDiG4/4+h4q60SNZgFlqJ9zwEgwR2u9zWcf1bxBdcIAvRN48 hdjPbwoDX7uIS6lTngUlOKhxCqH30U2ihVcgL6zP0uHhUlb0p7V62mOoxW296rkz277IX SoE6jIOs2EK/eYoLDgZqtUo/pw0IYutVFPFCuD5vRZLccEUUSR/QwrbjZvZMTtSMzBNuz ZA5CIeDObfDV8Y2yvTmw8jSMQrr63B0vtUL+/66yCPtT8+DV+FkUhCKVssNa2h3ParYzP dH8w7ximl90g2Vu/Ipt7JDJvwN9IVxCgn4KVOUtXW7TmzNv4nTN/pA1EjRmNscRWS1Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=IOL3M1mb; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E2EC606A337 for ; Tue, 3 Nov 2026 02:22:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=IOL3M1mb Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43D811F00A1D; Tue, 3 Nov 2026 02:22:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793672540; bh=b2YL294FU9QpZFiKRZDyCeHsQ5/dyMnUVgRpiRhxEPM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IOL3M1mbDUYM6eDIWSSOmK1rMZIM/KPqwKORy+xE/TYskTMU6k2g80QSHVn771wG+ ZiTL77egILfJ/G4Cg2XJvknuX0/Ie78xqqFBKB2Wz0OcGbnB6WiFMZ+HDKi8FjI9Bl 1KRkroevxvAhDXEFstG7n6735ur1KoFjS/gzXSedDVhi7dx/LjM6mUICPd/3Mzpzzr +7N8hKohsUTZ/Rq7KvWkyp0DP3RIP1PfggKUetvlclrbyTSnL1aIsbz8UQuGg7EZv4 fLy++cu7tRfge5zTbY1GKF06fs//PUHa1fBvq3p2lUr62htoVNnHqqFWkLRfrd8R7o a9Tw0fTP0pSIQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Zikang Gao <2715417602@qq.com>, David Howells , Paulo Alcantara , Sasha Levin Subject: [PATCH 6.1.y] smb: client: do not pass a NULL buf to is_oplock_break() Date: Mon, 2 Nov 2026 21:22:19 -0500 Message-ID: <20261103020041.2819615-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110215-underpay-cassette-20d6@gregkh> References: <2026110215-underpay-cassette-20d6@gregkh> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Zikang Gao <2715417602@qq.com> [ Upstream commit 2225ab306575e424b3dad2ee1be2521c89249d15 ] receive_encrypted_read() sets *num_mids = 1 and never writes the caller's bufs[]. Offload returns -1 with *num_mids = 0, so the demultiplex thread skips the frame. The inline decrypt path returns 0 even when smb2_find_mid() fails. cifs_demultiplex_thread() then treats mids[i] == NULL as an oplock break and calls is_oplock_break(bufs[i], server) with bufs[i] still NULL. smb2_is_valid_oplock_break() reads hdr.Command at offset 12 and oopses. A large encrypted READ whose MessageId does not match is enough to panic cifsd. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 100 Comm: cifsd RIP: smb2_is_valid_oplock_break+0xc8/0x2270 [cifs] cifs_demultiplex_thread Kernel panic - not syncing: Fatal exception Return -1 when inline decrypt finds no mid, and skip is_oplock_break() plus the unknown-frame dump when bufs[i] is NULL. receive_encrypted_standard() already assigns bufs[*num_mids]. Fixes: c42a6abe3012 ("CIFS: Add capability to decrypt big read responses") Assisted-by: LLM Signed-off-by: Zikang Gao <2715417602@qq.com> Reviewed-by: David Howells Signed-off-by: Paulo Alcantara Cc: stable@vger.kernel.org [ sashal: added braces around the existing NULL-MID branch to include the new assignment ] Signed-off-by: Sasha Levin --- fs/smb/client/connect.c | 4 +++- fs/smb/client/smb2ops.c | 5 +++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 157d947846d9b..f765246fa57c7 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -1324,12 +1324,14 @@ cifs_demultiplex_thread(void *p) mids[i]->callback(mids[i]); release_mid(mids[i]); - } else if (server->ops->is_oplock_break && + } else if (bufs[i] && server->ops->is_oplock_break && server->ops->is_oplock_break(bufs[i], server)) { smb2_add_credits_from_hdr(bufs[i], server); cifs_dbg(FYI, "Received oplock break\n"); } else { + if (!bufs[i]) + continue; cifs_server_dbg(VFS, "No task to wake, unknown frame received! NumMids %d\n", atomic_read(&mid_count)); cifs_dump_mem("Received Data is: ", bufs[i], diff --git a/fs/smb/client/smb2ops.c b/fs/smb/client/smb2ops.c index a7b884e8c3412..ab7ed90d6fb2b 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -5219,9 +5219,10 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid, goto free_pages; *mid = smb2_find_mid(server, buf); - if (*mid == NULL) + if (*mid == NULL) { cifs_dbg(FYI, "mid not found\n"); - else { + rc = -1; + } else { cifs_dbg(FYI, "mid found\n"); (*mid)->decrypted = true; rc = handle_read_data(server, *mid, buf, -- 2.53.0