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=1793208656; b=ObVaKVy2sWQsJ+RgLI0EnnVtqAH+/72Sxb6bfQ1oDeWpXW4SE73A9WMl+ZceU4CAaN36 xQp+3uRABhETZognlyJ2Q81q9aYSisfPvqtF2HHtsQskOJb73y64q4QUVu684ainEaso+ 3ut8m/ObMgccoDaPAIw8yXMzItpFq0U/eLbhp+IHHzJqg2eR+sD7aJ5PofPk5scaQltSU CC6BYCdhXSXh7O99vF4dm7d4HGVDrr1BYyyYbpoaYxgfPPIGVT8J561ePRkgaLLjuTM5G HUs9R3sTGxuLAbkTo1oTHDLEeriVv4cpttySbKx8AJ/UzENrPYEgDQOCUeBbXL63fyw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793208656; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=1XDEH7v6kmT+/v7aO/cRewbd4kloQtyFZgO3OSpE/ak=; b=Cuqj595X/ySdLUx6LlJ9q5uaT1W+/XKwUHMAX2drN+NMQ3DWjy0h/ngZd+K3dyLWEEsB I72bd6zpSeGFvETagH+wWWF+bc6CixHaRIZQWWKtfAzsdZXs7eLMoEDgmrJIwsxOiKYJy mvDlZGGuUXzb5QAArNJ9GVtwHT6PTIlj0G+5Nh2AfpmqmM9PXnjPCCGS5xIbUKHoVVed1 BOSlVVishfeOu0E8MLo4WhsgUj37McnaQwkBC0N3aJ4cGWc+QyzRRj9F3SLGSr/cgi9NK 3YgvUJ7cBPSOaH24cparGtPlWFtHqmyhbRtWfhsWrXoF99UHbpqzM/rT6/71MfmrArg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=1VKHCyk2; 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 5A635606A31A; Wed, 28 Oct 2026 17:30:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=1VKHCyk2 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A6F491F01825; Wed, 28 Oct 2026 17:30:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793208656; bh=1XDEH7v6kmT+/v7aO/cRewbd4kloQtyFZgO3OSpE/ak=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1VKHCyk2xC6hUrVBlchoL1UTsWBbiKPa/x/SLEhpXK6caJIAvFGqDzGSeEOxcAT/v tT7Gz3XNDRFFc3uKyyY9gsgrP3KRZptY/fdMqN6iLEnGJGVupyR6Ak/KB3XdD2xoGQ lCB/Yvi6ryuHOijzQbrrLDl/bo+PMO2gdD0LNXVQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@kernel.org, Yuchao Zhang , =?UTF-8?q?Micha=C5=82=20Nazarewicz?= Subject: [PATCH 5.10 197/516] usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC Date: Wed, 28 Oct 2026 17:55:49 +0100 Message-ID: <20261028170008.169491118@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170003.522232767@linuxfoundation.org> References: <20261028170003.522232767@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Yuchao Zhang commit 9cd072788c76595529eb38f42bf94d23852f8534 upstream. When user space sets up FunctionFS with only full-speed descriptors (e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a higher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER), config_ep_by_speed() detects that the function lacks descriptors for the current speed, logs a warning, and falls back to full-speed descriptors. The endpoint is then successfully enabled via usb_ep_enable(), and epfile->ep becomes valid. However, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC ioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the descriptor index solely based on gadget->speed: switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: case USB_SPEED_SUPER_PLUS: desc_idx = 2; break; case USB_SPEED_HIGH: desc_idx = 1; break; default: desc_idx = 0; } desc = epfile->ep->descs[desc_idx]; memcpy(&desc1, desc, desc->bLength); Because user space only supplied full-speed descriptors, epfile->ep->descs[1] is NULL. Dereferencing desc->bLength triggers an immediate kernel NULL pointer dereference panic. Fix this by falling back through lower speed descriptors if the current speed descriptor was not supplied, matching the fallback logic in config_ep_by_speed() and historical f_fs behavior. If still missing, fall back to epfile->ep->ep->desc (the active descriptor), and return -EINVAL safely if no valid descriptor is found. In addition, mark desc as const to match struct usb_ep::desc and avoid discarding qualifiers. Fixes: c559a3534109 ("usb: gadget: f_fs: add ioctl returning ep descriptor") Cc: stable@kernel.org Signed-off-by: Yuchao Zhang Acked-by: Michał Nazarewicz Link: https://patch.msgid.link/20260918005438.81263-2-ndaugoing@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_fs.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) --- a/drivers/usb/gadget/function/f_fs.c +++ b/drivers/usb/gadget/function/f_fs.c @@ -1338,8 +1338,9 @@ static long ffs_epfile_ioctl(struct file break; case FUNCTIONFS_ENDPOINT_DESC: { + const struct usb_endpoint_descriptor *desc; + struct usb_endpoint_descriptor desc1; int desc_idx; - struct usb_endpoint_descriptor desc1, *desc; switch (epfile->ffs->gadget->speed) { case USB_SPEED_SUPER: @@ -1353,7 +1354,17 @@ static long ffs_epfile_ioctl(struct file desc_idx = 0; } - desc = epfile->ep->descs[desc_idx]; + do { + desc = epfile->ep->descs[desc_idx]; + } while (!desc && --desc_idx >= 0); + + if (!desc) + desc = epfile->ep->ep->desc; + if (!desc) { + ret = -EINVAL; + break; + } + memcpy(&desc1, desc, desc->bLength); spin_unlock_irq(&epfile->ffs->eps_lock);