From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-vs1-f50.google.com (mail-vs1-f50.google.com [209.85.217.50]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 735FE4014AB for ; Thu, 21 May 2026 19:03:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.217.50 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779390237; cv=none; b=t/vuLHNFbn4RTM+3VJVpMH2FARJdDDMy2Tl+MR9vd09CdajSKScZjIVHnbHDSBL9L5HzOjh6wjvVod2AkoaQteFDN2cPWnus+9dtQkjifHwUNYH9pTLHKJyzdghX5HqbHu0fc36188EgKppFvR2wLpHqyZhnwiGL6+G+/5Y6qsM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779390237; c=relaxed/simple; bh=OkIJFj1WpHxPKkw7/vbBH23Sz9MpEmCSnLhzwZDR+Bo=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=Kn3NKwWhiOTNkAFdY343WRd/9Nw1j2op3eRqExnA8wjgFkr/vSo4oFBKUu1oO01dTzCNqpunYNZxsqyrM7jTX65CmrWl47wl5FBzPqU3NOIhb41bTdRyYeCgRrBJrzEwsBpnbukMhC0M5VuXj/92r+tCQbuLf1p4Qd/bGMIXK3c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=bvIRFEBj; arc=none smtp.client-ip=209.85.217.50 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="bvIRFEBj" Received: by mail-vs1-f50.google.com with SMTP id ada2fe7eead31-6314d2e31d6so2250119137.0 for ; Thu, 21 May 2026 12:03:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1779390222; x=1779995022; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=zgN6mf2S3Ka5W9KYYeUGfEraPnENfWLJguQUgwFYtak=; b=bvIRFEBj6ZDHSxgBm+gp0dWt00NwzcPbdZXCwJe7aGsNkshyFTFi8sXJxtNPM73uCD NQO/I1TtA0CbG0ds59UPoYmRESJP9Y8rRgEQMs5OtKdMZ6YWf4wdkIxxrSnTn8L5K2vl 87IAnBArT+JkPeOCchiz69xECFyK7hO1fjuiW7O15HYtqzXefp5G9YTzF7zP+8uDFhIm Pxu1y8ruTq+RqemYAU6A9jJ2s4KNv1BEZ6KuccCBN0N5K95ss1c0nWHniO8I3vkXoldU ahRwFwYqHQ9Sr7FkqiIIEeFNYkzT1O+vbtsehUPhwGz5E25UAM3Ktq87+pZEj/6iHtQW HysA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779390222; x=1779995022; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zgN6mf2S3Ka5W9KYYeUGfEraPnENfWLJguQUgwFYtak=; b=LmE0VjbbnOnMkctyinY27KedGAxQhACpOev2IFSS9JPU4v5IeC7swv8H686XrQ0iRi sZ6+v09u1Sv3AHU1nvjBVkrF2+N0dN3sNhEc4S48vppx2+SunsjjMlbX861VqG44zwgs rQpcYMJa9aUWVPmOPQvELSxH/+Cw9VU/7VxFx+X0b/gB8RJmosRqUhBS4ipd+afbt9/S 98akClRb2rZu0/34VlJrqiIlz3xlzkTofTUL/PfvKujKfDZt2icbkoj60O4IqMTwetwA sVerqmAEaEPvwxXXwyALT1DZh4DQ7R5K8QIit/BhVE7afViSC32SRf6Q3rvl5iVRWe+Y Dpjg== X-Gm-Message-State: AOJu0YzdUbrG8F0fjIxveF0mZdVjlle1a9d+1EpqVq1DgVQk2b3hyFkW YTmgTGFXuiVHt23oblDasMRripJ1qYinnNZhoOb/2+oQwb75djKIZFeqeuyV+Q== X-Gm-Gg: Acq92OGhFJ9kAk+lFwXz+49g1cohQtPYd65iIFWJuqdwgHif5SMacCODqcchkDqKTF6 lF7JTu5BKuZ2cjvRdD9AJAozf1ztjuGFcPIM3pFBX0U4SmnlWa3636B17vxz/1/+aUG4IDmtraP /Yu1CXU3KkIz6CWcRGNU0yPw1+9Ko5D3h8o3gUzWxA3aIHcFofZTD+fATCvK8tD3nhyNJtrzHWG qksKN4NdEXA8UaYfWfLYIjV/ufS18+cY3qyDj2AOqOlAwbECatRUafNWDmgmfK7ZUCmLmhqdUhc y9KkuuMKqpUlJVRJeh0axzHnJMjVYzW2AVyFfuGalTbYxAF47R9DAluyatpubtlDs3NJgD1DB3w QIvU4AOELZF6SgCOR10QC5b0zfIjlItxgfUvQJsP4cwzn4+XlrXSqpJ9ikY0Z0PQnHjGsmW9QLh hRFO2yOxXE23EYCt7EyQ9mjdOG9BoLzbJsEF8x5FXaoBDaWAp/QsjYnb0MZEaY0K8mDfPRsNJKg PUUbAWkhBVLB3W3Mw== X-Received: by 2002:a67:e7cb:0:b0:605:6773:611d with SMTP id ada2fe7eead31-67c7405f583mr138494137.1.1779390221893; Thu, 21 May 2026 12:03:41 -0700 (PDT) Received: from lvondent-mobl5 ([72.188.211.115]) by smtp.gmail.com with ESMTPSA id ada2fe7eead31-679ed329671sm1684947137.4.2026.05.21.12.03.40 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 May 2026 12:03:41 -0700 (PDT) From: Luiz Augusto von Dentz To: linux-bluetooth@vger.kernel.org Subject: [PATCH v3] Bluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp Date: Thu, 21 May 2026 15:03:32 -0400 Message-ID: <20260521190332.3171234-1-luiz.dentz@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-bluetooth@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Luiz Augusto von Dentz If dcid is received for an already-assigned destination CID the spec requires that both channels to be discarded, but calling l2cap_chan_del may invalidate the tmp cursor created by list_for_each_entry_safe and in fact it is the wrong procedure as the chan->dcid may be assigned previously it really needs to be disconnected. Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so instead schedule l2cap_chan_timeout with delay 0 to close the channel asynchronously. Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode") Signed-off-by: Luiz Augusto von Dentz --- net/bluetooth/l2cap_core.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 5668c92b3f58..5ae34bbcc5b2 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -5244,7 +5244,7 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, struct l2cap_ecred_conn_rsp *rsp = (void *) data; struct hci_conn *hcon = conn->hcon; u16 mtu, mps, credits, result; - struct l2cap_chan *chan, *tmp; + struct l2cap_chan *chan, *tmp, *orig = NULL; int err = 0, sec_level; int i = 0; @@ -5264,7 +5264,7 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, list_for_each_entry_safe(chan, tmp, &conn->chan_l, list) { u16 dcid; - if (chan->ident != cmd->ident || + if (orig == chan || chan->ident != cmd->ident || chan->mode != L2CAP_MODE_EXT_FLOWCTL || chan->state == BT_CONNECTED) continue; @@ -5283,8 +5283,10 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, BT_DBG("dcid[%d] 0x%4.4x", i, dcid); + orig = __l2cap_get_chan_by_dcid(conn, dcid); + /* Check if dcid is already in use */ - if (dcid && __l2cap_get_chan_by_dcid(conn, dcid)) { + if (dcid && orig) { /* If a device receives a * L2CAP_CREDIT_BASED_CONNECTION_RSP packet with an * already-assigned Destination CID, then both the @@ -5293,10 +5295,16 @@ static inline int l2cap_ecred_conn_rsp(struct l2cap_conn *conn, */ l2cap_chan_del(chan, ECONNREFUSED); l2cap_chan_unlock(chan); - chan = __l2cap_get_chan_by_dcid(conn, dcid); - l2cap_chan_lock(chan); - l2cap_chan_del(chan, ECONNRESET); - l2cap_chan_unlock(chan); + l2cap_chan_lock(orig); + /* Disconnect the original channel as it may be + * considered connected since dcid has already been + * assigned; don't call l2cap_chan_close directly + * since that could lead to l2cap_chan_del and then + * removing the channel from the list while we're + * iterating over it. + */ + __set_chan_timer(orig, 0); + l2cap_chan_unlock(orig); continue; } -- 2.53.0