[freetype2] master 10d8de7: [truetype] Fix UBSan warning on offset to nullptr (#57501).

[Werner LEMBERG]

branch: master
commit 10d8de7541ab1f26f6f04b2118d13a92a7119102
Author: Dominik Röttsches <address@hidden>
Commit: Werner Lemberg <address@hidden>

    [truetype] Fix UBSan warning on offset to nullptr (#57501).
    
    * src/truetype/ttinterp.c (Ins_CALL): Fail if `exc->FDefs' is null.
---
 ChangeLog               | 6 ++++++
 src/truetype/ttinterp.c | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 5447fc4..f7f2d68 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-02  Dominik Röttsches  <address@hidden>
+
+       [truetype] Fix UBSan warning on offset to nullptr (#57501).
+
+       * src/truetype/ttinterp.c (Ins_CALL): Fail if `exc->FDefs' is null.
+
 2019-12-31  Nikhil Ramakrishnan  <address@hidden>
 
        [woff2] Allow bitmap-only fonts (#57394).
diff --git a/src/truetype/ttinterp.c b/src/truetype/ttinterp.c
index dca11d7..56cf53b 100644
--- a/src/truetype/ttinterp.c
+++ b/src/truetype/ttinterp.c
@@ -3965,6 +3965,9 @@
     if ( BOUNDSL( F, exc->maxFunc + 1 ) )
       goto Fail;
 
+    if ( !exc->FDefs )
+      goto Fail;
+
     /* Except for some old Apple fonts, all functions in a TrueType */
     /* font are defined in increasing order, starting from 0.  This */
     /* means that we normally have                                  */