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 1C4DA509EE4; Wed, 30 Sep 2026 15:40:17 +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=1790782821; cv=none; b=f2Gvff15l1W7cDpvoY6LMXu7Df8K6p9OXUHHFrAEJpdwL9gDIHWRBvOqBvxt/yCM3z6juIdQ1itCS7fCvELlCUDvWlu/Dgif1uFSBMr9klIp1tgaHwZ37U2vR8suOjuDGROySfdXAw6q8FQa7h4XxDBUB+09gZWC8FVBxnPm4nA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790782821; c=relaxed/simple; bh=NYMrhdxa6cO+7sox2QyLguazJL20G2dzNuDdNMMHsRM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kEOp+XD0qe8RLVZUmlz7mbbzvm9Qcb//TJQvN5t7gMbwDI8oYu6SZBJKAj4MWuqgMexlbX7crBTZbNdjG09H2tng9/fjyrC6ZKYaMSRp5LrOZ+NY84z8cTKO8n+KamHrC7tt3Z6sLzzZ6fx+xvWn8YSgQbSker021J+Fg8MEaPw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pVch+1US; 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="pVch+1US" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05D751F00899; Wed, 30 Sep 2026 15:40:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790782817; bh=/bYmoJ3pP1RCE3/E6WP9v1bWsRCbEf7zASZdKfqjlH8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=pVch+1USZ4gUzb+1b62C3v0Zpbu6bwojKN4hAE0SZwhbRIY3m/gO2t16L06fUjjIG 4YXUkjRNeor+xUJ5kCxSgTa3BQRdGVhwAGjw9OoqtOICrLNQy4sqEOICBKX0PdS8NG QqJYxeVRUmoJVGmHpB31HneLRl3FBWKdOFjT86N4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiale Yao , Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 5.10 180/595] Bluetooth: RFCOMM: validate skb length in rfcomm_recv_frame Date: Wed, 30 Sep 2026 17:21:13 +0200 Message-ID: <20260930152351.612620329@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152347.700140858@linuxfoundation.org> References: <20260930152347.700140858@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: Jiale Yao [ Upstream commit b230e5bf501c5edaf2eb0991cb862ac142031d4b ] rfcomm_recv_frame() casts skb->data to struct rfcomm_hdr and dereferences hdr->addr and hdr->ctrl without validating skb->len first. A truncated frame with skb->len less than the minimum header size causes an out-of-bounds read of uninitialized memory. Additionally, a zero-length frame causes skb->len-- to underflow to UINT_MAX, making skb_tail_pointer() read far past the buffer. Commit 23882b828c3c ("Bluetooth: RFCOMM: validate skb length in MCC handlers") fixed the same class of missing-length-check bugs in the MCC sub-handlers, but the top-level rfcomm_recv_frame() was left unfixed. KMSAN reports: BUG: KMSAN: uninit-value in rfcomm_run ... Uninit was created at: __alloc_skb+0x474/0xb60 vhci_write+0xe9/0x870 Fix this by rejecting frames smaller than sizeof(struct rfcomm_hdr) + 1 (the minimum frame must have a 3-byte header and a 1-byte FCS). Signed-off-by: Jiale Yao Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/rfcomm/core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bluetooth/rfcomm/core.c b/net/bluetooth/rfcomm/core.c index 828c18d91e829..05f576463a27f 100644 --- a/net/bluetooth/rfcomm/core.c +++ b/net/bluetooth/rfcomm/core.c @@ -1782,6 +1782,11 @@ static struct rfcomm_session *rfcomm_recv_frame(struct rfcomm_session *s, return s; } + if (skb->len < sizeof(*hdr) + 1) { + kfree_skb(skb); + return s; + } + dlci = __get_dlci(hdr->addr); type = __get_type(hdr->ctrl); -- 2.53.0