From 47e5dec521ab6243c9b249dd65b93d232d90d6b1 Mon Sep 17 00:00:00 2001 From: Jan Dittberner Date: Thu, 25 Aug 2016 17:13:49 +0200 Subject: [PATCH] Apply patch to fix CVE-2016-6318 This patch fixes an issue with a stack-based buffer overflow whne parsing large GECOS field. See https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-6318 and https://security-tracker.debian.org/tracker/CVE-2016-6318 for more information. Signed-off-by: Stefan Sørensen --- Status: upstream, not yet released. lib/fascist.c | 57 ++++++++++++++++++++++++++++++++----------------------- 2 files changed, 34 insertions(+), 24 deletions(-) diff --git a/lib/fascist.c b/lib/fascist.c index a996509..d4deb15 100644 --- a/lib/fascist.c +++ b/lib/fascist.c @@ -502,7 +502,7 @@ FascistGecosUser(char *password, const char *user, const char *gecos) char gbuffer[STRINGSIZE]; char tbuffer[STRINGSIZE]; char *uwords[STRINGSIZE]; - char longbuffer[STRINGSIZE * 2]; + char longbuffer[STRINGSIZE]; if (gecos == NULL) gecos = ""; @@ -583,38 +583,47 @@ FascistGecosUser(char *password, const char *user, const char *gecos) { for (i = 0; i < j; i++) { - strcpy(longbuffer, uwords[i]); - strcat(longbuffer, uwords[j]); - - if (GTry(longbuffer, password)) + if (strlen(uwords[i]) + strlen(uwords[j]) < STRINGSIZE) { - return _("it is derived from your password entry"); - } + strcpy(longbuffer, uwords[i]); + strcat(longbuffer, uwords[j]); - strcpy(longbuffer, uwords[j]); - strcat(longbuffer, uwords[i]); + if (GTry(longbuffer, password)) + { + return _("it is derived from your password entry"); + } - if (GTry(longbuffer, password)) - { - return _("it's derived from your password entry"); - } + strcpy(longbuffer, uwords[j]); + strcat(longbuffer, uwords[i]); - longbuffer[0] = uwords[i][0]; - longbuffer[1] = '\0'; - strcat(longbuffer, uwords[j]); + if (GTry(longbuffer, password)) + { + return _("it's derived from your password entry"); + } + } - if (GTry(longbuffer, password)) + if (strlen(uwords[j]) < STRINGSIZE - 1) { - return _("it is derivable from your password entry"); + longbuffer[0] = uwords[i][0]; + longbuffer[1] = '\0'; + strcat(longbuffer, uwords[j]); + + if (GTry(longbuffer, password)) + { + return _("it is derivable from your password entry"); + } } - longbuffer[0] = uwords[j][0]; - longbuffer[1] = '\0'; - strcat(longbuffer, uwords[i]); - - if (GTry(longbuffer, password)) + if (strlen(uwords[i]) < STRINGSIZE - 1) { - return _("it's derivable from your password entry"); + longbuffer[0] = uwords[j][0]; + longbuffer[1] = '\0'; + strcat(longbuffer, uwords[i]); + + if (GTry(longbuffer, password)) + { + return _("it's derivable from your password entry"); + } } } } -- 2.9.3