Bug 1768555 (CVE-2019-5094)

Summary: CVE-2019-5094 e2fsprogs: Crafted ext4 partition leads to out-of-bounds write
Product: [Other] Security Response Reporter: Guilherme de Almeida Suckevicz <gsuckevi>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: esandeen, josef, kasal, kzak, lczerner, oliver, sct
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: e2fprogs 1.45.4 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2020-04-28 16:34:30 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 1768556, 1768709, 1768710, 1783777, 1792192    
Bug Blocks: 1768557    

Description Guilherme de Almeida Suckevicz 2019-11-04 17:32:12 UTC
An exploitable code execution vulnerability exists in the quota file functionality of E2fsprogs 1.45.3. A specially crafted ext4 partition can cause an out-of-bounds write on the heap, resulting in code execution. An attacker can corrupt a partition to trigger this vulnerability.


Comment 1 Guilherme de Almeida Suckevicz 2019-11-04 17:32:29 UTC
Created e2fsprogs tracking bugs for this issue:

Affects: fedora-all [bug 1768556]

Comment 2 Eric Sandeen 2019-11-04 18:01:52 UTC
This is fixed by:

commit 8dbe7b475ec5e91ed767239f0e85880f416fc384
Author: Theodore Ts'o <tytso>
Date:   Sun Sep 1 00:59:16 2019 -0400

    libsupport: add checks to prevent buffer overrun bugs in quota code
    A maliciously corrupted file systems can trigger buffer overruns in
    the quota code used by e2fsck.  To fix this, add sanity checks to the
    quota header fields as well as to block number references in the quota
    Addresses: CVE-2019-5094
    Addresses: TALOS-2019-0887
    Signed-off-by: Theodore Ts'o <tytso>

Comment 4 Huzaifa S. Sidhpurwala 2019-11-05 04:09:29 UTC
Analysis notes:

This flaw is triggered by a malformed/specially-crafted ext2/3/4 partition. You need to run the e2fsck utility on the said partition in order to trigger the flaw. Since the e2fsck cannot only be run as a privileged  user, the attacker will need to social engineer/convince the system administrator to run this utility on the corrupted partition. Also the corrupted partition will first need to exists on the system either via a locally attached hard drive or a network device.

Based on the above, it seems like exploiting this flaw will need some previous privileged access on the system by the attacker.

Comment 8 Huzaifa S. Sidhpurwala 2019-11-05 04:20:07 UTC
External References:


Comment 9 errata-xmlrpc 2020-04-28 16:08:24 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2020:1913 https://access.redhat.com/errata/RHSA-2020:1913

Comment 10 Product Security DevOps Team 2020-04-28 16:34:30 UTC
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):


Comment 11 errata-xmlrpc 2020-09-29 20:34:14 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7

Via RHSA-2020:4011 https://access.redhat.com/errata/RHSA-2020:4011