From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f174.google.com (mail-qk1-f174.google.com [209.85.222.174]) (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 7B1F739CCF9 for ; Fri, 17 Jul 2026 10:40:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.174 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784284837; cv=none; b=N4KySCmZCJ/2NAUXo/RhyshHq2dQGYFxyPTtcOHWfRSsxbr+8jxuo6JOOZXCwa7mXcXG5C25mnpUJNg+Ajbe5EbkTw/sOXdSIKp4EqwBAhFzzgVhMXdLY3VkY5i0a3UO950iBVMivGbfuxO4N4peTESNSWEAnhkqb6c1Q1SlpGs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784284837; c=relaxed/simple; bh=EVMh4EJnBmbgwEy5VQ90Q076Mfc9GXnTaanW3sM92JA=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=j6wP24t3vq6McVNfRyvi3VLk68LAsKPK2ethDu2FJt5LENCRdcgQhkEtBcbigh4VAsJOrE5Y8GB13BPWegdDmfkRXKzgMmpYogi2jaBgPcvuR0ik548CHhQZ0b0WJTtHHpifd73qgOcYe/d+u9kBVwforjjgKnA9T+AdP86nPZE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=trailofbits.com; spf=pass smtp.mailfrom=trailofbits.com; dkim=pass (2048-bit key) header.d=trailofbits.com header.i=@trailofbits.com header.b=Qfxa00C8; arc=none smtp.client-ip=209.85.222.174 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=trailofbits.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=trailofbits.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=trailofbits.com header.i=@trailofbits.com header.b="Qfxa00C8" Received: by mail-qk1-f174.google.com with SMTP id af79cd13be357-9217d13c276so565510685a.1 for ; Fri, 17 Jul 2026 03:40:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=trailofbits.com; s=google; t=1784284835; x=1784889635; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=henLu2wLIlaVqokG1wD2FoMayR14wq1gWRo/m1wfX/M=; b=Qfxa00C88YvKhdO+kX07CrmZWwOYJGZW2fjBOcJcWB8FCd5aDOGFhEx6vt9rYF4PRN zUjxW25xJvCWMWVnmd+XqJKeqcBP64aGxFW6VwnltXQDdtsNd+7AHoJeFuAuaPqlQF+B /b2sEA5hImp6T0s/DVqBkRzZ7pQZ3E0OWocf06tuJ6Kfk1YYb+MlkRrNNDrGI5JNyKmP EjXsDgOn0n5eq0/AE1PJHpuDf1BGoGDohWseMPMTroxj8y8NBZc+Cir7hJLqA3RwhTr6 WDzo7yJ/t1BgX6rz5MPZj660byZjX8gbCEjvxfuJX5zXyPm5mvlsvge17fZstzVnofeU QuAQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784284835; x=1784889635; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=henLu2wLIlaVqokG1wD2FoMayR14wq1gWRo/m1wfX/M=; b=FJ+XGwnGU4hwX0tEecEDOVklNLRGctQY9ahW1vt6dD0RaP0TgH+XVc5SFsTbiCIbmS Dpqklo/FlnMValAtokHxrqDZEaZQnzu68xPd7wKkyBt5lGkxdO5H0qum7y1fuEEqpPD6 SgTUoP/PYODFLbMK4fp/DSUOqgDd67MSTy8Sp2Go6Oh+mYrIuej/3TTpU2ZlXAgUqvNG Carlr2Bc1PXjFSgYPJcLSXro8Moqk+9ROL8a6ZQyEeEENYULopWjSH8CHyOzYozdvisx 1AtRYS2O5CzndKisINlvYfrlcXti8l/FtgQNJEEf1VSXsaLOxlCO1KMGgisBplDFTcJT iClw== X-Forwarded-Encrypted: i=1; AHgh+RoNhnJqKqXYc3LahFbP9UFqtQ76yYb83pVvr1piyheMDSiGJwVvbF6E5hwW+NohCZ8ld6hhEBtAbZ0+ffs=@vger.kernel.org X-Gm-Message-State: AOJu0Yw5fgJeeWccVWdheHVhuOT9RwgiccgHIhPgWvvVv4gUXBgRGGTg zf4EVsag5Gd3IYBKgcT7RbXq5lghjK+6vOGCBFCuh4PBIqxfrq6dJi+4v6+sstqR37Q= X-Gm-Gg: AfdE7cnULhjH+J6TA8Njvk2jzDGJPzMR0WedBi+ZsXy0Ret6E/5XnOAH2DN0Nma4ttA D00vEtMAnNFY7DsGh72ymZ18dEq0+K4r7ZloOsFtdfL10GpV2Ep0Xnb88wUipq7IdrVH4cJ99gg H0CwatGQ8ziZPA3CI3gt7SxymbfOlzH32KXNmC6PMrMPKDoaxcpqVEtfuqq9IG/TyKPqfVG+wta gDs8j8vArqLx+LTeYo3kV9FuKuJRkBj3GNIiNzZdEX7KwPt1PZqku3//+epVOsR8qjCEwBQH3Fo jMCu46pE/wqVi3U55X0y2aNEiredtNUvUuhEGi+NfPoDmis+vQSW+e8I57raXTPzZF/k6IdMNQ6 T/PDrRCLE0hQg6Bq1CXvZ94C999L0dyIskGBioDUiUkB/jSeWUYQSZP13Oskgtuz6+GQhIWDi5x Q4IdAiKNk= X-Received: by 2002:a05:620a:7014:b0:92e:4867:95af with SMTP id af79cd13be357-930b4323a4dmr197784685a.73.1784284835379; Fri, 17 Jul 2026 03:40:35 -0700 (PDT) Received: from localhost ([146.190.222.192]) by smtp.gmail.com with UTF8SMTPSA id af79cd13be357-930b52dd4fasm121848085a.4.2026.07.17.03.40.34 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 17 Jul 2026 03:40:34 -0700 (PDT) From: David Lee To: Alexander Viro Cc: David Lee , Christian Brauner , Jan Kara , Kees Cook , linux-fsdevel@vger.kernel.org, Dominik 'Disconnect3d' Czarnota , linux-kernel@vger.kernel.org Subject: [PATCH] ufs: reject oversized cylinder group metadata Date: Fri, 17 Jul 2026 10:40:32 +0000 Message-ID: <20260717104033.38574-1-david.lee@trailofbits.com> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The on-disk cylinder group size becomes the fragment count used by ufs_read_cylinder(). A size larger than one filesystem block makes that count exceed UFS_MAXFRAG and drives buffer-head stores beyond the fixed eight-entry array in struct ufs_cg_private_info. Reject zero-sized cylinder groups and sizes larger than the validated filesystem block size while reading the superblock. Since a filesystem block contains at most UFS_MAXFRAG fragments, every later cylinder cache count is then bounded by its buffer-head array. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Assisted-by: Codex:gpt-5.5 Signed-off-by: David Lee --- fs/ufs/super.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/ufs/super.c b/fs/ufs/super.c index c4831a8b9b3f..fa2effdec7b0 100644 --- a/fs/ufs/super.c +++ b/fs/ufs/super.c @@ -1140,6 +1140,11 @@ static int ufs_fill_super(struct super_block *sb, struct fs_context *fc) uspi->s_cssize = fs32_to_cpu(sb, usb1->fs_cssize); uspi->s_cgsize = fs32_to_cpu(sb, usb1->fs_cgsize); + if (uspi->s_cgsize == 0 || uspi->s_cgsize > uspi->s_bsize) { + pr_err("%s(): invalid cylinder group size %u\n", + __func__, uspi->s_cgsize); + goto failed; + } uspi->s_ntrak = fs32_to_cpu(sb, usb1->fs_ntrak); uspi->s_nsect = fs32_to_cpu(sb, usb1->fs_nsect); uspi->s_spc = fs32_to_cpu(sb, usb1->fs_spc); -- 2.43.0