From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 0B60DDF40 for ; Mon, 15 May 2023 16:36:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F2C8C433D2; Mon, 15 May 2023 16:36:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684168610; bh=ypxJasnUqLk7S4UiAsFHgDnLBTl9EFSMR1YVWGCUaJ4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=n9LdynhaMJUlspFmwy+0ffAvihkreF5zjmmQlCeb0Qq1U6dBkkrVyzsqjRf+GupB+ 4jmcingTT7NKisndM9VFJ8Wy/GiRsQDLiaW01j3YHV4juSVQw8Izqy3i3SV90hIhr4 arpDOSFLy54RukPbyKsILMw5c9ZT3oRfNtZYLG0g= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+1966db24521e5f6e23f7@syzkaller.appspotmail.com, stable@kernel.org, Theodore Tso Subject: [PATCH 4.14 107/116] ext4: add bounds checking in get_max_inline_xattr_value_size() Date: Mon, 15 May 2023 18:26:44 +0200 Message-Id: <20230515161701.794953464@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161658.228491273@linuxfoundation.org> References: <20230515161658.228491273@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Theodore Ts'o commit 2220eaf90992c11d888fe771055d4de330385f01 upstream. Normally the extended attributes in the inode body would have been checked when the inode is first opened, but if someone is writing to the block device while the file system is mounted, it's possible for the inode table to get corrupted. Add bounds checking to avoid reading beyond the end of allocated memory if this happens. Reported-by: syzbot+1966db24521e5f6e23f7@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?extid=1966db24521e5f6e23f7 Cc: stable@kernel.org Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inline.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/fs/ext4/inline.c +++ b/fs/ext4/inline.c @@ -38,6 +38,7 @@ static int get_max_inline_xattr_value_si struct ext4_xattr_ibody_header *header; struct ext4_xattr_entry *entry; struct ext4_inode *raw_inode; + void *end; int free, min_offs; if (!EXT4_INODE_HAS_XATTR_SPACE(inode)) @@ -61,14 +62,23 @@ static int get_max_inline_xattr_value_si raw_inode = ext4_raw_inode(iloc); header = IHDR(inode, raw_inode); entry = IFIRST(header); + end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; /* Compute min_offs. */ - for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { + while (!IS_LAST_ENTRY(entry)) { + void *next = EXT4_XATTR_NEXT(entry); + + if (next >= end) { + EXT4_ERROR_INODE(inode, + "corrupt xattr in inline inode"); + return 0; + } if (!entry->e_value_inum && entry->e_value_size) { size_t offs = le16_to_cpu(entry->e_value_offs); if (offs < min_offs) min_offs = offs; } + entry = next; } free = min_offs - ((void *)entry - (void *)IFIRST(header)) - sizeof(__u32);