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 B386830C165 for ; Fri, 3 Jul 2026 18:38:20 +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=1783103901; cv=none; b=hu7FbQx2bD4+dK7mJblE9fuBQHne5jGLZdV9oHENfgbpifJaULfJGi3V8hwufhFaSVRda4hv3G315sNMuUBP/XDkn8F/f/ldfN5lE98sxKOwdjcV9nVhhlCfdv+HkP59IkPIUj5tr6YuujY41oRus+NYCdSxN2iNsw9zsnxt17w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783103901; c=relaxed/simple; bh=2k4IBV4qSlWgZwQFIGO2yMwOwYTADvuecIV84Or3e8Q=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FaXUP9zs3DoSYARxF7iXJ4gpws0lBMaG7RW4bZC7RwPSRMgGUWTPTzxZ68peyMYkxkdXIxpx2o7WzM/1iRr4nvotE9mqQ3BF9eAjcT7ySPSsGtiNVRxciVW9UAHaOiNm3WrSIk0zv4/iFBARwHo903SRH45kFkCtlxVawmC3LgM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DhqT2GEL; 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="DhqT2GEL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C578F1F000E9; Fri, 3 Jul 2026 18:38:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783103900; bh=I2ZQevghA8vyulxxy9stWaHgdCZkCwN6ndxv0Zm1N44=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DhqT2GELAUbVzuIT80MsduRvSOXWNaBI9FbAqVvoExWcGKupicujSe63Ytil4i4v3 eikdhvnrl1gTJY2yQXYZs8zoxYC+tBCrjvX2MEH5F/KA53yda+6X8AjCs4rT96CBnQ IhqNMkAy0eSzkntKUNo6LCVp6TYAtDq+F/Pss5MQxxJVlfSUWIksitI1CWypvjXGnj yalDXt7p0EgAQjd549rIgMuRVI5qxbuYiHPeLIAhO5GjvzabBzsX8Du/D9lXsnb/4a krNxJDpP0V0iCiniJZuxkulmm3GrGGq4dkKNSI5id/nwcA6uaQ2Yb+ZilAFv2GaV19 Pf9DJLP6XuNNw== From: Sasha Levin To: stable@vger.kernel.org Cc: Bryam Vargas , Chao Yu , Jaegeuk Kim , Sasha Levin Subject: [PATCH 5.15.y] f2fs: bound i_inline_xattr_size for non-inline-xattr inodes Date: Fri, 3 Jul 2026 14:38:18 -0400 Message-ID: <20260703183818.261657-1-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <2026070208-stiffly-pyromania-4a20@gregkh> References: <2026070208-stiffly-pyromania-4a20@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 | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c index 7494a68a53196f..3e1b2a9b5b6f36 100644 --- a/fs/f2fs/inode.c +++ b/fs/f2fs/inode.c @@ -258,14 +258,15 @@ static bool sanity_check_inode(struct inode *inode, struct page *node_page) return false; } - if (f2fs_has_extra_attr(inode) && - f2fs_sb_has_flexible_inline_xattr(sbi) && - f2fs_has_inline_xattr(inode) && - (!fi->i_inline_xattr_size || - fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE)) { + if (f2fs_sb_has_flexible_inline_xattr(sbi) && + (fi->i_inline_xattr_size > MAX_INLINE_XATTR_SIZE || + (f2fs_has_inline_xattr(inode) && + fi->i_inline_xattr_size < + sizeof(struct f2fs_xattr_header) / sizeof(__le32)))) { set_sbi_flag(sbi, SBI_NEED_FSCK); - f2fs_warn(sbi, "%s: inode (ino=%lx) has corrupted i_inline_xattr_size: %d, max: %zu", + f2fs_warn(sbi, "%s: inode (ino=%lx) has corrupted i_inline_xattr_size: %d, min: %zu, max: %zu", __func__, inode->i_ino, fi->i_inline_xattr_size, + sizeof(struct f2fs_xattr_header) / sizeof(__le32), MAX_INLINE_XATTR_SIZE); return false; } -- 2.53.0