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=1794063276; b=Uq9yF3Jgv9bo5Gv14anubTUq+0TaWclzgV9CSS5WFlyust582k9FEBc0wCB+0+ZXRpBV Yo7b1FHM6FjvsaxNjRVlPpwzogH8r4r+/DZD3PgedCyZ4Stypgt0cHK4GQZrM/T65U+KU VExZu3ZoLNwTJbu5mEfHdz2QmWTRrWcPdHBXuB+A/LhIy2CRgNYHewek78HA8FUz2xE3n 26ryLH6nc20ZYGKDae6axKrlRzxtdb5MIOhsxFI7gteyKYkcxeOP1Yx1b3dhWGXss33LI hD4REYXtBYIqE77UIG7KIEyhSEUfXzrviHS0AOWedfMKniUxsHL3Djstga+f/Q622Lg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794063276; 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-Transfer-Encoding; bh=3vXjwtzG4m44EBVKgQD5LYHrNo/mCJuQ6NS26APexAQ=; b=wMQG8Jb9QvR31sku5dCsY9AKJq+4kd2MFEHMaeBpQztdxJ7e/HcU6r1JQwBGTgbsOFLo L3lJRwxx/9+XS2sXqqc1SPi5u1tp4UAmYOA96Mn+loEsJVjEWFysO+xjnTZDVSOJptrHG H4M35KGjmTMxCLXRdyuzQdDR3MmHeaLCEZ8XlOuR80G1taycF/G7WRbRR7BBkMRoacQ1N iDokdGlWSd/XoklTYRdtv3ZQrnArKvD6c7+K4CoiaG6jaa+LBBU/mp2r5S18+CLC6D55W LS/NyT07a1hgHa0BNMslSMbLm2I+ZpRnm/INVIE6qIef23lv24Q/ZdJ3XzEgOO4Gb5w== 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="tlsMkFX/"; 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 78B74606A337; Sat, 7 Nov 2026 14:54:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=tlsMkFX/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24C4A1F0089F; Sat, 7 Nov 2026 14:54:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794063276; bh=3vXjwtzG4m44EBVKgQD5LYHrNo/mCJuQ6NS26APexAQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=tlsMkFX/hAQhhJpc0skl7nOrmCrKW7TaWKUArUp0YAp5d4aPDLvahxkRSFUU9Bhsm 9V9EE8f2oVOkHQVFjsuGVTQeuKp/BjrRf7f+B/N9Tklg2Di1mKuDtmlUTXlsRQOniz F4B6mUWvx+a5c3HK0/AGfDRn6ZANlkMua9gOMF18= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qu Wenruo , Hengyu Liang , David Sterba , Sasha Levin Subject: [PATCH 6.18 472/869] btrfs: return -ENOTTY for unknown ioctls on the control device Date: Sat, 7 Nov 2026 08:52:34 -0500 Message-ID: <20261107134909.628407144@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134852.069646174@linuxfoundation.org> References: <20261107134852.069646174@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Hengyu Liang [ Upstream commit 9985f1643ac3f8595862e2f82108f0ccae4cf959 ] Commit 5ab2b180884c ("btrfs: factor out validation of btrfs_ioctl_vol_args::name") made btrfs_control_ioctl() store the result of btrfs_check_ioctl_vol_args_path() in ret before it looks at the command. However, ret is initialized to -ENOTTY and the switch has no default case, so this initial value was what an unknown command returned. As of now, every unknown ioctl on /dev/btrfs-control returns 0. A tool that tries a control ioctl which the running kernel does not have is told that the ioctl succeeded. The issue can be reproduced with a simple C program, run as root: #include #include #include int main(void) { static char buf[4096]; int fd = open("/dev/btrfs-control", O_RDWR); if (ioctl(fd, TCGETS, buf) < 0) perror("ioctl"); else printf("ioctl succeeded\n"); return 0; } Before commit 5ab2b180884c ("btrfs: factor out validation of btrfs_ioctl_vol_args::name"), the result is: ioctl: Inappropriate ioctl for device After that commit, the result is: ioctl succeeded This patch will add a default case that returns -ENOTTY. Fixes: 5ab2b180884c ("btrfs: factor out validation of btrfs_ioctl_vol_args::name") CC: stable@vger.kernel.org Reviewed-by: Qu Wenruo Signed-off-by: Hengyu Liang Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin --- fs/btrfs/super.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 6cc4fe2ccd8a7..61a0575fd162a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -2284,6 +2284,9 @@ static long btrfs_control_ioctl(struct file *file, unsigned int cmd, case BTRFS_IOC_GET_SUPPORTED_FEATURES: ret = btrfs_ioctl_get_supported_features((void __user*)arg); break; + default: + ret = -ENOTTY; + break; } out: -- 2.53.0