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=1793663396; b=UD3+EiFKMMUYtd2RFzhFl0p6vurSBaXM6qYW4e4pff1ww9YW6hGQ/sGxY0dQ25Os5YC0 /xf7iwQo/4pxpg0QK/qZneT0WbDBXnBkB2+yzLK+kiVb8kywphc5pQlImmJpCN9CZ5e8Y g0eN6W00FaQsOJ2UmT7Yr9hHqqLhAItu0uUhB7la203BwKC4YHXImksAfrpJQKzp1L+Ji 2H7e3+7nQmDrlRXMM1mdLkczqOiZMSRqeChu2BC/ThGCTZH8IiWDZneuJ+J5Ak+DeXxYv T3FD0ErD1BMIyOT5HZDYpE6jSZaprAjIhlXKFcMKLkQVeU+PxgwS7IMvOcwKWUTD9GQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793663396; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=zS/70lzOc5uq92zhpWECnTO2t8BcmxJuzYjr0GWM7xY=; b=r2kcg4Y8CoFeUW67Hx9jkT4/qhNPRM+yT9sN5VOyJfwd3Jdq/s/2/4wI4gsbB5P5Xljv o+G2uFrP9xXqnG5wOWDo7lujhUZY8NC//YXnmXPldGxRZVVSzJTEWIIq/nvFaSnm5IX/D oRGI6WdtKE7LvrWvyaFwCGLOQAlPjoRn5W+UZpFoGBGqD2mXutPGtJ74PEnTNrgw8PFvv vTQfdwyJFoBgYkxFTpGZJIMTM2e3f/T2xxWs/P4Ra5RLboeiUWRYQFDFkGJD0JFdYacsK xA1NsdYcDbnY0yjmysC0QNQjf6U05+zToLIlqIc6W7c0efHuJUW3VpwRzu0JlyqY18Q== 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=jUKboSEQ; 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 BAD17606A336 for ; Mon, 2 Nov 2026 23:49:55 +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=jUKboSEQ Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5EA71F00A16; Mon, 2 Nov 2026 23:49:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793663395; bh=zS/70lzOc5uq92zhpWECnTO2t8BcmxJuzYjr0GWM7xY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=jUKboSEQNj4liNC/H/7u10HfHn7/0jaInzmxzMHBDgoDATuMopSrLWfYf5tYADLff Xc17ocSH8SWEzKPG9pZBlhbTg661vrLLM8eTOSzHrGrn53RQOB+FwGO2Cd1HhoP4Td e4rdNc3QNBi2ABXHSZsZYaNTa3+wURBgb0V9uiRDU7+zqFjOa8454nXaEUKkmFtkAY Akfaabh7K3AGky/a66GfO42zAkL0FCtyoRLwKH7jJpGd1cnQoWn2icL8ARowLexxKH 2Ey/cQ2pN5mLOZquliYGzRAj8QO0bdBHUGNFMUGLwWKkQoxUp27yHKcYgBHM7vDgqn cxNgLNR4Woa3g== From: Sasha Levin To: stable@vger.kernel.org Cc: Zikang Gao <2715417602@qq.com>, David Howells , Paulo Alcantara , Sasha Levin Subject: [PATCH 6.6.y] smb: client: do not pass a NULL buf to is_oplock_break() Date: Mon, 2 Nov 2026 18:49:53 -0500 Message-ID: <20261102234412.2560495-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026110214-audience-apostle-d632@gregkh> References: <2026110214-audience-apostle-d632@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: adjusted context for older MID callback and release APIs ] Signed-off-by: Sasha Levin --- fs/smb/client/connect.c | 4 +++- fs/smb/client/smb2ops.c | 1 + 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/fs/smb/client/connect.c b/fs/smb/client/connect.c index 1c21ae3d61e24..e56a2501465b0 100644 --- a/fs/smb/client/connect.c +++ b/fs/smb/client/connect.c @@ -1335,12 +1335,14 @@ 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 f657d9696d1da..12c6c6f1c504b 100644 --- a/fs/smb/client/smb2ops.c +++ b/fs/smb/client/smb2ops.c @@ -5027,6 +5027,7 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid, *mid = smb2_find_mid(server, buf); if (*mid == NULL) { cifs_dbg(FYI, "mid not found\n"); + rc = -1; } else { cifs_dbg(FYI, "mid found\n"); (*mid)->decrypted = true; -- 2.53.0