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=1793210959; b=1NHX/XYdAgJOsjGpWApsXkhkCmwNND2Thcc0CPD7iKS/E8JeoVqjtDhD4FMNB36M/CpL y9thuxHQy1FeGWAj51ICZWyQOBoEntVlBkC6zxVk9iPynFpugvg3R0esLmBoae9jHQK8b EMTnsn9P5lnSoPcMlDd1dx6fWPvhI9Udr2OVEGxVzWvKAuBRzBIFURr/GTwzh5o+7wxGN 7AbDeVU2llEldVvu2gVTWZ3wc+Nh1joQuRSySv4Kc0FdPPH0WF6dPde7d3BORIhm5eFhM 11lUpR+jRYUcyAs/F130CwXDlbLR2siCRbNGvTvOk4U+hXkzbOkDBx5MZfeb0NYVovQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210959; 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=IeONskHq/Htz7VDUskedKTohiF9/TsRn7i2K6Ajsy6g=; b=nJ/pRjT9RBsLBv6u2PumYuGmu1PnS3v+5JWoR6xZoLYwS1B6geB5SKStSVcGUZzv5fm8 s678S1bVxb4sOKEVbuCICCxERw4M1P2diLDWfJh+/qwU+kdAWPqCTEqRUgBRQ6NAVls+Z gOBPOE5TRey7Ar3cvKpNjR/JwVfbJxGUO3+jX8DANfHzOgcZElSCy2IODCzku69qbza5i 98yhqOZ2YUbK99a2Mgfsn2PW3sFOGh5/rMtgFBWuhyW8pf9JCTXfBG8escbohYBTKm6om 5skFAHff9mDKxBumIcsJ2FhQ0SnltpPfhi6v33uFzhIpaXKsXDka8NZADG5PxiWuXnA== 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=RBdiJ+71; 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 F2BC9606A31D; Wed, 28 Oct 2026 18:09:18 +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=RBdiJ+71 Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D7FD1F01825; Wed, 28 Oct 2026 18:09:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210958; bh=IeONskHq/Htz7VDUskedKTohiF9/TsRn7i2K6Ajsy6g=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RBdiJ+71NitFMoFA9non2GAX6bXNyAJJjetjyYTqtntog8Sb4YUhn2Z3GmzzxOWx6 9Hj3up5tfgEbinnuA80ETaBemu3Fb/vj08z2kpioXgwIRyV5X3rEviXYesEMZWvFpF HhIme52lqLQWR0X1MXkSJ2bN482EL2thVdXw6sQM= 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 5.15 208/571] usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC Date: Wed, 28 Oct 2026 17:55:55 +0100 Message-ID: <20261028170012.938941228@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@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 5.15-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 @@ -1351,8 +1351,9 @@ 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: @@ -1366,7 +1367,17 @@ 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);