martin/emacs
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Fix undefined behavior when fetching glyphs from the display vector.

Browse Source 
You can trigger this rather obscure bug by enabling selective display
if the second glyph in its display vector has an invalid face.  For
example, evaluate

(set-display-table-slot standard-display-table
                        'selective-display [?A (?B . invalid)])

and then enable selective display.

* src/xdisp.c (next_element_from_display_vector): Check whether next
glyph code is valid before accessing it.
This commit is contained in:
Philipp Stephani
2020-11-09 22:14:39 +01:00
parent 78e1646bf7
commit 109eb1e7e2
1 changed files with 3 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
src/xdisp.c
View File

@@ -8221,10 +8221,10 @@ next_element_from_display_vector (struct it *it)
next_face_id = it->dpvec_face_id;
else
{
int lface_id =
GLYPH_CODE_FACE (it->dpvec[it->current.dpvec_index + 1]);
Lisp_Object gc = it->dpvec[it->current.dpvec_index + 1];
int lface_id = GLYPH_CODE_P (gc) ? GLYPH_CODE_FACE (gc) : 0;
if (lface_id > 0)
if (lface_id > 0)
next_face_id = merge_faces (it->w, Qt, lface_id,
it->saved_face_id);
}