From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) (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 6E7791F2380 for ; Tue, 14 Apr 2026 13:04:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.214.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776171860; cv=none; b=Pa2KYW/qTKhH4JlKvXwFXyZtXBwPB8XBS4I8wbWFyUVm71j6gikUNoZXNCa7y9jRZVKbwp+mxz2maEYEx+5cOTdlZO5J3/oZZex74oHpt3xOuntXS4UvpItkcsFUpk4Uk8HzHwra/8EZGq8Y2z/YDryywX/ME8UHx9I4uLGcad4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776171860; c=relaxed/simple; bh=4/AER0+79jUWl6FaRfWd3aGY/aJ6MEcGm48BpGjFB+k=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=q20F/E0Vb6I+QJVIGabg8VK50mmk7b+fVEZWYy/doQBXVD7kicO1H+Uop4PdMW8KIFEE6Es7MbHy9FfGP8+QnOvRn578G6JLUAeLWDREiyJl0Xkn4chZrRg3VKIHciSiCZbQyLmaBjOQULl/Ch3VrESu66Lej1FCtWmLHS9PXiw= 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=C9aVets9; arc=none smtp.client-ip=209.85.214.172 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="C9aVets9" Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-2ab08e6c553so5655335ad.3 for ; Tue, 14 Apr 2026 06:04:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1776171859; x=1776776659; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=opcylBd2GGN1SyilCKpA4V3rg0BLKqf3938q77JOvpk=; b=C9aVets9yeSzJe9hZrf9sflWrbgaQDVXGBVkHRK4icRXkXC04qXsI6dSoFwVLqQYuT 7ZWEcH0DQNUsDbeusJxX90smZZIBFq8yQur4Az364q5KUSrGmLpL2ZA65+RjlCoh40z1 sfNToR4EGSxF8jlRc7x8be6y4MGqoYswm4RUdImfPkrfeNQO/QrLbLjOLzzbjEKKioYl 7xic3EY/Pk6Lb8RTuirLJcRr1Z21Ji/xaeSoB74lTXR7p2bU/jOS6psQ8j6apm5uOBcT NffVGuxH6Cx5+VMmTxvkxnWKkDq7uHXqQT2G3YlDEt/gtp9XnmhKZxzZtIJLnfCCMmFy XcLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1776171859; x=1776776659; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=opcylBd2GGN1SyilCKpA4V3rg0BLKqf3938q77JOvpk=; b=haboWpFSwmNXV6KkbV1yW1cufltPpD0QFW0rGMZXTNH/rQME+AjwrN7oj6CPTD6Zj5 Kx/Ot9FtIJp7dBIENInGEw9Y52ggwtnGZXauHQzxQL8NEnClU5gPBIvgPxYh6nIGKNz/ TiJXZaaPnrnH8ug1Ud5l/kT9Mj/2obxS5ZKTZiiLTvia5y9x+ViTKAAhJz1sirutYHtI O5V8x9UcoYKG5XTPSUoTdjpjOunFRx+i9VeNYmVXj9ECJoUJ27tN3jbdXVceKoy9Y6uF yhen0zAVsN93VQ0zagujFEB9TJR3jejw82ZG9b52ymcCXYy+J1R6J7NmS8TOdw30Y//c WSNQ== X-Forwarded-Encrypted: i=1; AFNElJ9lkQzAa3au2GGxx4qJT1R1NtcTfQMsSlN3KEUMU7AeUZaww2K3LYrZegOmVDfYEG47JsBZTCE=@vger.kernel.org X-Gm-Message-State: AOJu0YxKJFqeFqNm4hs2DcM9qVa9znGVsiMM0o4tFxfKQszF/60o65IL 5K4fU6TCcIGceFQTuqDU/Wt1SNikGnDRMClTgDgC0FN9LdMm3xzuXb4Y X-Gm-Gg: AeBDietiLeU1eXUK9/n4EegUDTLDup9L0FlqYMSo2Lxp4U4amyr6KdXqL8UfuMpRnrS dEaUxI/H7A82O0JbBxfGYfkeLM2kZ3OZBvLNB+dlOJ91bf9LHGFpjL00zTRjEsUFA9/pNIUc7cb AwBQsHKb5V7PdL59keNOOZOx5uCu+305IZuDGuI6+1bsHdjCsCa9KgAJfwo42L8pSB6As7MlN5J LZvYsiXo12kSjqLsS2BBHgKZAg9mSNZnA49JEgNE3a/+F7GQZsB5MVtl3J601KFwgjNfXeXu8Fa XCGXHlCGtnfj7IgIcNOMzakxJuwHrjQCBz7ZzdVf+HVx9PA7VJ4M+kvq17R9OEd4UBeR9cPS4tn vqyM/0kXMkhnGJH+8xXm4vtdlEzyL7JcScsfyQYCWHwdFkp7O9ka0hzrGt6MfXiU8ZDvB4o1XVr hr4pb+o7khjl8EDSWgwwMRrHX8rtRKLhC/PICgKE3YalUtYxPLDtCGL13w0RzwsPj2aWm9eXU= X-Received: by 2002:a17:902:b213:b0:2b2:aa7b:b3bd with SMTP id d9443c01a7336-2b2d5a6e4famr76571835ad.6.1776171858706; Tue, 14 Apr 2026 06:04:18 -0700 (PDT) Received: from mi-HP-ProDesk-680-G6-PCI-Microtower-PC ([43.224.245.229]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2b45d066afesm70522445ad.8.2026.04.14.06.04.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Apr 2026 06:04:18 -0700 (PDT) From: Ziqing Chen X-Google-Original-From: Ziqing Chen To: tiwai@suse.com, perex@perex.cz Cc: linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ziqing Chen Subject: [RESEND PATCH] ALSA: control: Validate buf_len before strnlen() in snd_ctl_elem_init_enum_names() Date: Tue, 14 Apr 2026 21:03:33 +0800 Message-ID: <20260414130333.244544-1-chenziqing@xiaomi.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <87ik9tsukj.wl-tiwai@suse.de> References: <87ik9tsukj.wl-tiwai@suse.de> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit snd_ctl_elem_init_enum_names() advances pointer p through the names buffer while decrementing buf_len. If buf_len reaches zero but items remain, the next iteration calls strnlen(p, 0). While strnlen(p, 0) returns 0 and would hit the existing name_len == 0 error path, CONFIG_FORTIFY_SOURCE's fortified strnlen() first checks maxlen against __builtin_dynamic_object_size(). When Clang loses track of p's object size inside the loop, this triggers a BRK exception panic before the return value is examined. Add a buf_len == 0 guard at the loop entry to prevent calling fortified strnlen() on an exhausted buffer. Found by kernel fuzz testing through Xiaomi Smartphone. Fixes: 8d448162bda5 ("ALSA: control: add support for ENUMERATED user space controls") Cc: stable@vger.kernel.org Signed-off-by: Ziqing Chen --- sound/core/control.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/core/control.c b/sound/core/control.c index 0ddade871b52..6ceb5f977fcd 100644 --- a/sound/core/control.c +++ b/sound/core/control.c @@ -1574,6 +1574,10 @@ static int snd_ctl_elem_init_enum_names(struct user_element *ue) /* check that there are enough valid names */ p = names; for (i = 0; i < ue->info.value.enumerated.items; ++i) { + if (buf_len == 0) { + kvfree(names); + return -EINVAL; + } name_len = strnlen(p, buf_len); if (name_len == 0 || name_len >= 64 || name_len == buf_len) { kvfree(names); -- 2.52.0