From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E05ED34F270 for ; Fri, 3 Jul 2026 14:09:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783087779; cv=none; b=KLTp1Tus5km+RQNZqMQJqTQVYUi51k+dg//+XWWtfyaYzPwaJL8PjRRd9IB5hwZ9m6uetyYv2Sqzn2ctoz0S2+MG+8/9uJzbmly6kZjNq884iRwLQNrVCsleq6Qy+Dx7UMw2t0d0zMdctICnFbyuXePBAIbpasyg1pQ+ut4XBik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783087779; c=relaxed/simple; bh=JIjw4BcPDDEBdk7dnObLb6u3MuShdNJLj1HvXx9GqJc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qSmCG4ayZjnxlBxxUlJ0ZGFU6Z8EGV1HpVEQl8EzuKK6Dy9OYN9yHs3Qnxv+No1BuIPT3DLJ328+KUqNEYEE2yxyF0xW4pluaMzvPfL1AGv+j5Q7+KW/UITojqIpb3rkZhUfjGUu/1E9k2zXvv/BzJnhWS3NHO0Jpgjei39/si0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IZy76w8X; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IZy76w8X" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F25B81F000E9; Fri, 3 Jul 2026 14:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783087777; bh=V6S2cQ8cQs03vQyemoqkIaF+YbM1OZ904N49hXuGajQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IZy76w8XHj+4Rza+9MRcF26Di3akDa8yRpCniAjAPlEbz4Yow+V8YfkC5QCK/fWNe vYRkHgNQiY4qfNEKbqbVQdo3QB3RJqCLkPO+BpW4f5264cNWs6kiC/TsIYpRfqHqbW pDXotIzqdSs6ncFsUqIT8ExSNr2B2htIbJploCbiAxJxNSnaK3J5KpnGaUpjkwjc3q 3jAcjFFYc01w+eGfoQL+PY54a6SpCjDevVTyaDS915budC4gbg+FaYR9u9lHoue1HY kr0yuZ+jK9qyHMdnvA2vVGJvhak/e+pAjkzbXWnAAewrnF0EPaJvPZYenEf1Zm/JUl Q0wbFoxaBpqAA== From: Sasha Levin To: stable@vger.kernel.org Cc: Bryam Vargas , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 6.18.y] f2fs: bound i_inline_xattr_size for non-inline-xattr inodes Date: Fri, 3 Jul 2026 10:09:34 -0400 Message-ID: <20260703140934.18093-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026070205-tattoo-circling-7d61@gregkh> References: <2026070205-tattoo-circling-7d61@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Bryam Vargas [ Upstream commit 378acf3cf19b6af6cba55e8dd1154c4e1504bae8 ] When the flexible_inline_xattr feature is enabled, do_read_inode() loads the on-disk i_inline_xattr_size unconditionally: if (f2fs_sb_has_flexible_inline_xattr(sbi)) fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size); but sanity_check_inode() only range-checks it when the inode also has the FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline data but not FI_INLINE_XATTR -- the normal layout for an inline directory -- therefore keeps a fully attacker-controlled i_inline_xattr_size from a crafted image. get_inline_xattr_addrs() returns that value with no flag gating, so it feeds the inode geometry: MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1) NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...) addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY() negative, so make_dentry_ptr_inline() sets d->max (int) to a negative value. The inline directory walk then compares an unsigned long bit_pos against that negative d->max, which is promoted to a huge unsigned bound, and reads far past the inline area: while (bit_pos < d->max) /* fs/f2fs/dir.c */ ... test_bit_le(bit_pos, d->bitmap) / d->dentry[bit_pos] ... Mounting a crafted image and reading such a directory triggers an out-of-bounds read in f2fs_fill_dentries(); the same underflow also corrupts ADDRS_PER_INODE for regular files. Validate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the flexible_inline_xattr feature is enabled -- i.e. whenever the value is loaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE bound gated on inodes that actually carry an inline xattr, so legitimate inodes with i_inline_xattr_size == 0 are still accepted. Cc: stable@vger.kernel.org Fixes: 6afc662e68b5 ("f2fs: support flexible inline xattr size") Signed-off-by: Bryam Vargas Reviewed-by: Chao Yu Signed-off-by: Jaegeuk Kim Signed-off-by: Sasha Levin --- fs/f2fs/inode.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 49470f4c9362a0..1caa84c15c9969 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -318,9 +318,9 @@ static bool sanity_check_inode(struct inode *inode, struct folio *node_folio) } if (f2fs_sb_has_flexible_inline_xattr(sbi) && - f2fs_has_inline_xattr(inode) && - (fi->i_inline_xattr_size < MIN_INLINE_XATTR_SIZE || - fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE)) { + (fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE || + (f2fs_has_inline_xattr(inode) && + fi->i_inline_xattr_size < MIN_INLINE_XATTR_SIZE))) { f2fs_warn(sbi, "%s: inode (ino=%lx) has corrupted i_inline_xattr_size: %d, min: %zu, max: %lu", __func__, inode->i_ino, fi->i_inline_xattr_size, MIN_INLINE_XATTR_SIZE, MAX_INLINE_XATTR_SIZE); -- 2.53.0