From nobody Sun Apr 5 13:07:30 2026 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 15BD6327C07; Wed, 18 Feb 2026 10:14:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771409663; cv=none; b=Dv81K0IXrdKqZ6xye+0Xx2apagR1Dp6wr6uoM64V37vHwlMPwTbMC4RI/zAfQj86v2m9Zpe91n9JW1//ymE2kJV5++18Hy8vaMPlS2Tna7z1hgY3F99oukigIabwzfT96gY2sl+EKLH0i1J5lMFeafBLYV53KdG2CRBexcA/ZHY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771409663; c=relaxed/simple; bh=NSL8LXlakBuOU2+iw8RIEkJEzD0nTYZ79OcqylTu4Os=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Qxp7izRmQKhhJSu13gClJardepCKCAULNw5pryCLCHQlyBl3OXiNTtmzAmE0Xs78BVqIoJitfHNFXYbABYrHYv3R+WuLg/uAUDZlvKuEU74RxXXqnXmJdfy7JZTHYj3Y3dM2vgN/ixWk2tCKssVwXt/KImoP79DJ53d3AN1TJeg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y8qr5pAW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y8qr5pAW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0BFAAC19421; Wed, 18 Feb 2026 10:14:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771409662; bh=NSL8LXlakBuOU2+iw8RIEkJEzD0nTYZ79OcqylTu4Os=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y8qr5pAWP24BGVzg7TLAL49mzjXojiCEIHA/AwcUoYUHt0K95993aluTyLKLNRAXz 2ZPpTko5b17LNEsD1CyPh1tG8Pb4n83ZLAIvvHibxW4qx09UGk0hEo6+e3GxMDC+qO hJkDg9xHsJPwaBjxLuLnsTZYSoFRkRoG6eWh6OSBE0ZTQ138+dffFxtFAhn2NKDQ23 3Ua/juQ8XtRyxGXSZpqVji5biMvUXBdTDKfrj6Qq0rwA2KVyOmsupH4kEGecvo/tB0 5OYm37tKF9PUYoFGcz1RsRk915N7HBX7sCi8jusvZq5LAksVB2keKIBZHsgmbVEL6u Cq4/TrRAPeo5w== From: "Masami Hiramatsu (Google)" To: Steven Rostedt Cc: Masami Hiramatsu , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH v2 1/4] ring-buffer: Fix to check event length before using Date: Wed, 18 Feb 2026 19:14:20 +0900 Message-ID: <177140966034.1537493.2009658315480887232.stgit@mhiramat.tok.corp.google.com> X-Mailer: git-send-email 2.53.0.310.g728cabbaf7-goog In-Reply-To: <177140965047.1537493.15501794841217306382.stgit@mhiramat.tok.corp.google.com> References: <177140965047.1537493.15501794841217306382.stgit@mhiramat.tok.corp.google.com> User-Agent: StGit/0.19 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable From: Masami Hiramatsu (Google) Check the event length before adding it for accessing next index in rb_read_data_buffer(). Since this function is used for validating possibly broken ring buffers, the length of the event could be broken. In that case, the new event (e + len) can point a wrong address. To avoid invalid memory access at boot, check whether the length of each event is in the possible range before using it. Fixes: 5f3b6e839f3c ("ring-buffer: Validate boot range memory events") Cc: stable@vger.kernel.org Signed-off-by: Masami Hiramatsu (Google) --- kernel/trace/ring_buffer.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index d33103408955..f7fd4bdf6560 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1849,6 +1849,7 @@ static int rb_read_data_buffer(struct buffer_data_pag= e *dpage, int tail, int cpu struct ring_buffer_event *event; u64 ts, delta; int events =3D 0; + int len; int e; =20 *delta_ptr =3D 0; @@ -1856,9 +1857,12 @@ static int rb_read_data_buffer(struct buffer_data_pa= ge *dpage, int tail, int cpu =20 ts =3D dpage->time_stamp; =20 - for (e =3D 0; e < tail; e +=3D rb_event_length(event)) { + for (e =3D 0; e < tail; e +=3D len) { =20 event =3D (struct ring_buffer_event *)(dpage->data + e); + len =3D rb_event_length(event); + if (len <=3D 0 || len > tail - e) + return -1; =20 switch (event->type_len) {