fontforge/SOURCES/fontforge-20170731-cve-2020-5395.patch
2021-09-09 16:42:46 +00:00

79 lines
3.0 KiB
Diff

From 048a91e2682c1a8936ae34dbc7bd70291ec05410 Mon Sep 17 00:00:00 2001
From: Skef Iterum <unknown>
Date: Mon, 6 Jan 2020 03:05:06 -0800
Subject: [PATCH] Fix for #4084 Use-after-free (heap) in the
SFD_GetFontMetaData() function Fix for #4086 NULL pointer dereference in the
SFDGetSpiros() function Fix for #4088 NULL pointer dereference in the
SFD_AssignLookups() function Add empty sf->fontname string if it isn't set,
fixing #4089 #4090 and many other potential issues (many downstream calls
to strlen() on the value).
---
fontforge/sfd.c | 19 ++++++++++++++-----
fontforge/sfd1.c | 2 +-
2 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/fontforge/sfd.c b/fontforge/sfd.c
index 731be201e0..e8ca39ba83 100644
--- a/fontforge/sfd.c
+++ b/fontforge/sfd.c
@@ -4032,13 +4032,16 @@ static void SFDGetSpiros(FILE *sfd,SplineSet *cur) {
while ( fscanf(sfd,"%lg %lg %c", &cp.x, &cp.y, &cp.ty )==3 ) {
if ( cur!=NULL ) {
if ( cur->spiro_cnt>=cur->spiro_max )
- cur->spiros = realloc(cur->spiros,(cur->spiro_max+=10)*sizeof(spiro_cp));
+ cur->spiros = realloc(cur->spiros,
+ (cur->spiro_max+=10)*sizeof(spiro_cp));
cur->spiros[cur->spiro_cnt++] = cp;
}
}
- if ( cur!=NULL && (cur->spiros[cur->spiro_cnt-1].ty&0x7f)!=SPIRO_END ) {
+ if ( cur!=NULL && cur->spiro_cnt>0
+ && (cur->spiros[cur->spiro_cnt-1].ty&0x7f)!=SPIRO_END ) {
if ( cur->spiro_cnt>=cur->spiro_max )
- cur->spiros = realloc(cur->spiros,(cur->spiro_max+=1)*sizeof(spiro_cp));
+ cur->spiros = realloc(cur->spiros,
+ (cur->spiro_max+=1)*sizeof(spiro_cp));
memset(&cur->spiros[cur->spiro_cnt],0,sizeof(spiro_cp));
cur->spiros[cur->spiro_cnt++].ty = SPIRO_END;
}
@@ -7992,10 +7995,12 @@ bool SFD_GetFontMetaData( FILE *sfd,
else if ( strmatch(tok,"LayerCount:")==0 )
{
d->had_layer_cnt = true;
- getint(sfd,&sf->layer_cnt);
- if ( sf->layer_cnt>2 ) {
+ int layer_cnt_tmp;
+ getint(sfd,&layer_cnt_tmp);
+ if ( layer_cnt_tmp>2 ) {
sf->layers = realloc(sf->layers,sf->layer_cnt*sizeof(LayerInfo));
memset(sf->layers+2,0,(sf->layer_cnt-2)*sizeof(LayerInfo));
+ sf->layer_cnt = layer_cnt_tmp;
}
}
else if ( strmatch(tok,"Layer:")==0 )
@@ -8948,6 +8953,10 @@ exit( 1 );
}
}
+ // Many downstream functions assume this isn't NULL (use strlen, etc.)
+ if ( sf->fontname==NULL)
+ sf->fontname = copy("");
+
if ( fromdir )
sf = SFD_FigureDirType(sf,tok,dirname,enc,remap,had_layer_cnt);
else if ( sf->subfontcnt!=0 ) {
diff --git a/fontforge/sfd1.c b/fontforge/sfd1.c
index cf931059d0..b42f832678 100644
--- a/fontforge/sfd1.c
+++ b/fontforge/sfd1.c
@@ -674,7 +674,7 @@ void SFD_AssignLookups(SplineFont1 *sf) {
/* Fix up some gunk from really old versions of the sfd format */
SFDCleanupAnchorClasses(&sf->sf);
- if ( sf->sf.uni_interp==ui_unset )
+ if ( sf->sf.uni_interp==ui_unset && sf->sf.map!=NULL )
sf->sf.uni_interp = interp_from_encoding(sf->sf.map->enc,ui_none);
/* Fixup for an old bug */