Bug 1413890 (CVE-2017-5356)

Summary:	CVE-2017-5356 irssi: Out-of-bounds read in format string
Product:	[Other] Security Response	Reporter:	Andrej Nemec <anemec>
Component:	vulnerability	Assignee:	Red Hat Product Security <security-response-team>
Status:	CLOSED WONTFIX	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	huzaifas, jskarvad, mmahut, rosser.bjr
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	irssi 0.8.21, irssi 1.0.0	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-02-28 16:30:54 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1410829, 1410830
Bug Blocks:	1410833

Description Andrej Nemec 2017-01-17 09:12:32 UTC

A vulnerability was found in irssi. Printing the value %[ leads to out-of-bounds read.

CVE assignment:

http://seclists.org/oss-sec/2017/q1/77

Comment 1 Andrej Nemec 2017-01-17 09:14:15 UTC

Created irssi tracking bugs for this issue:

Affects: fedora-all [bug 1410829]
Affects: epel-5 [bug 1410830]

Comment 2 Cedric Buissart 2017-02-27 13:31:51 UTC

Corresponding patch for CVE-2017-5356 :
---8<---
--- a/src/fe-common/core/formats.c   2010-04-03 18:19:24.000000000 +0200
+++ b/src/fe-common/core/formats.c   2017-02-24 16:53:56.663978694 +0100
@@ -68,7 +68,7 @@ static void format_expand_code(const cha

        if (flags == NULL) {
                /* flags are being ignored - skip the code */
-               while (**format != ']')
+               while (**format != ']' && **format != '\0')
                        (*format)++;
                return;
        }
@@ -161,6 +161,10 @@ int format_expand_styles(GString *out, c
        case '[':
                /* code */
                format_expand_code(format, out, flags);
+               if ((*format)[0] == '\0')
+                       /* oops, reached end prematurely */
+                       (*format)--;
+               
                break;
        default:
                /* check if it's a background color */
--->8---

Comment 4 Cedric Buissart 2017-02-28 16:29:56 UTC

Lowering the impact to low : the attacker would need to trick user into loading a maliciously crafted theme, or running a malicious command in order to crash irssi.

Comment 5 Cedric Buissart 2017-02-28 16:31:04 UTC

Statement:

Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.