From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AB8JxZp0i/49sNK9SUOkv6N3/UsVFXVl8ZMce0R/O8VkpY3LWmLJfh0k8RObCShhsM0/8iBUl1uY ARC-Seal: i=1; a=rsa-sha256; t=1525116344; cv=none; d=google.com; s=arc-20160816; b=P9UBzhMXLOBMw15fH5l6rWDIcscTHVObjxIUhVJjERkmQz2/bNBoj4HbGcpcNG0+Vg 8P2LR/a9mCeMqa/wFT6yAahRmH9s4Lij1cjVBeW4xKkbKIxp80YszxhCcKk5lhMUfQSs DjPVoaRHyrXOFhDxNKvUmbNEiGruHCBNcJyMSzp/0QHIiLFQoPEOI86BBWBsOc0R3/x5 bLAJmBKcc33FnHDFlqXG+ksFIptg/BVAk/rgpBqMMqRgFmrxqrLTliX38a1xEHxHX/Ir rd5TyNQ6799RjwjZUt/YnL+e+4y5vIoJh5KFVuej87Qh63luwu2Sp4E9H6OGasRr//JW q7yQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:dmarc-filter:arc-authentication-results; bh=iXWq/wutiUxkxGSu6xmQ54d66+D1od9+u6F+FPi1lco=; b=K7igKfENZCKP4KvXvzhaseI+zKemq5Rlet6BptKe0dUQd+c/ms/fEjl58eIHr9F+ZH YG199Lz2kg2pUBfnE0VQkBABXpkchi8xXrhhAE8wrgkttgtFvqUN3sa2CJ5F/DaLafur J4EWK/I1bSJ4CgZeAkv3kXakV3qwrPfyQn+iMDwNR7BPbxXhHq8dXa1WCS08vbXQS7qO gxH3I9AI2qvymxD5MxGbwH+2bteQxuHQBOHmB3TaeHV+UafPDKd5wArSrMbJWX9W7j5q ihUTF4BHHlB4OVlcUkv7sWIWIKK/mK62KKSQXylz26fRu9CwZGgFRMmUZM+5mJ+nZmVg tmjQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of srs0=k66p=ht=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=K66P=HT=linuxfoundation.org=gregkh@kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of srs0=k66p=ht=linuxfoundation.org=gregkh@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=SRS0=K66P=HT=linuxfoundation.org=gregkh@kernel.org DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BF0F521746 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=fail smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, syzbot+06c885be0edcdaeab40c@syzkaller.appspotmail.com, Eric Biggers , Theodore Tso Subject: [PATCH 4.4 01/44] ext4: prevent right-shifting extents beyond EXT_MAX_BLOCKS Date: Mon, 30 Apr 2018 12:24:12 -0700 Message-Id: <20180430190946.371502271@linuxfoundation.org> X-Mailer: git-send-email 2.17.0 In-Reply-To: <20180430190946.093694747@linuxfoundation.org> References: <20180430190946.093694747@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1599200396004789064?= X-GMAIL-MSGID: =?utf-8?q?1599200396004789064?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Biggers commit 349fa7d6e1935f49bf4161c4900711b2989180a9 upstream. During the "insert range" fallocate operation, extents starting at the range offset are shifted "right" (to a higher file offset) by the range length. But, as shown by syzbot, it's not validated that this doesn't cause extents to be shifted beyond EXT_MAX_BLOCKS. In that case ->ee_block can wrap around, corrupting the extent tree. Fix it by returning an error if the space between the end of the last extent and EXT4_MAX_BLOCKS is smaller than the range being inserted. This bug can be reproduced by running the following commands when the current directory is on an ext4 filesystem with a 4k block size: fallocate -l 8192 file fallocate --keep-size -o 0xfffffffe000 -l 4096 -n file fallocate --insert-range -l 8192 file Then after unmounting the filesystem, e2fsck reports corruption. Reported-by: syzbot+06c885be0edcdaeab40c@syzkaller.appspotmail.com Fixes: 331573febb6a ("ext4: Add support FALLOC_FL_INSERT_RANGE for fallocate") Cc: stable@vger.kernel.org # v4.2+ Signed-off-by: Eric Biggers Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/extents.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5380,8 +5380,9 @@ ext4_ext_shift_extents(struct inode *ino stop = le32_to_cpu(extent->ee_block); /* - * In case of left shift, Don't start shifting extents until we make - * sure the hole is big enough to accommodate the shift. + * For left shifts, make sure the hole on the left is big enough to + * accommodate the shift. For right shifts, make sure the last extent + * won't be shifted beyond EXT_MAX_BLOCKS. */ if (SHIFT == SHIFT_LEFT) { path = ext4_find_extent(inode, start - 1, &path, @@ -5401,9 +5402,14 @@ ext4_ext_shift_extents(struct inode *ino if ((start == ex_start && shift > ex_start) || (shift > start - ex_end)) { - ext4_ext_drop_refs(path); - kfree(path); - return -EINVAL; + ret = -EINVAL; + goto out; + } + } else { + if (shift > EXT_MAX_BLOCKS - + (stop + ext4_ext_get_actual_len(extent))) { + ret = -EINVAL; + goto out; } }