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| author | Stephan Bergmann <sbergman@redhat.com> | 2020-09-10 15:18:03 +0200 |
|---|---|---|
| committer | Stephan Bergmann <sbergman@redhat.com> | 2020-09-10 15:36:34 +0200 |
| commit | 42e1738baebbf82e71d2a8f156b023339d0a4c92 (patch) | |
| tree | f1bbd96e4abeea9e56c14209c625141f60a4edb6 /pango | |
| parent | 51b2b2231b85af7fe4ade4ec98129b28182f7148 (diff) | |
| download | pango-42e1738baebbf82e71d2a8f156b023339d0a4c92.tar.gz | |
Let get_items_log_attrs take the start-of-text offset into account
...when interpreting item->offset values.
I ran into this when executing tests of recent LibreOffice master with ASan on
Fedora 32 (with pango-1.44.7-2.fc32.x86_64), where one of the tests renders
various dialogs with a Tamil localization and failed with
> ==97247==ERROR: AddressSanitizer: SEGV on unknown address 0x60b000210006 (pc 0x7fd6c5b22b54 bp 0x61d0004b4150 sp 0x7fff107a0d18 T0)
> ==97247==The signal is caused by a READ memory access.
> #0 in g_utf8_get_char at ../glib/gutf8.c:319:37 (/lib64/libglib-2.0.so.0 +0x85b54)
> #1 in break_indic at ../pango/break-indic.c:119:17 (/lib64/libpango-1.0.so.0 +0x1076d)
> #2 in break_script at ../pango/break.c:1896:7 (/lib64/libpango-1.0.so.0 +0x1076d)
> #3 in tailor_break at ../pango/break.c:1606:9 (/lib64/libpango-1.0.so.0 +0x147db)
> #4 in pango_tailor_break at ../pango/break.c:1774:7 (/lib64/libpango-1.0.so.0 +0x147db)
> #5 in get_items_log_attrs at ../pango/pango-layout.c:4032:7 (/lib64/libpango-1.0.so.0 +0x2729c)
> #6 in pango_layout_check_lines at ../pango/pango-layout.c:4289:7 (/lib64/libpango-1.0.so.0 +0x2729c)
> #7 in pango_layout_get_extents_internal at ../pango/pango-layout.c:2623:3 (/lib64/libpango-1.0.so.0 +0x29068)
> #8 in gtk_label_get_measuring_layout at /usr/src/debug/gtk3-3.24.22-1.fc32.x86_64/gtk/gtklabel.c:3376:3 (/lib64/libgtk-3.so.0 +0x2454d0)
[...]
From some debugging, it smells like `pango_layout_check_lines` calls
`pango_itemize_with_base_dir` to compute `state.items` that are relative to the
beginning of `layout->text`, but then passes `state.items` together with the
offset'ed `start` into `get_items_log_attrs`, so that the latter misinterpreted
the items' locations relative to the offset'ed start.
Just adding
g_assert (item->offset <= length);
g_assert (item->length <= length - item->offset);
to the original `get_items_log_attrs` would make various tests in the `meson
test` suite fail, but which pass again with the complete fix, matching the above
speculation.
Diffstat (limited to 'pango')
| -rw-r--r-- | pango/pango-layout.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/pango/pango-layout.c b/pango/pango-layout.c index 7d5b9b10..68ffd190 100644 --- a/pango/pango-layout.c +++ b/pango/pango-layout.c @@ -4088,6 +4088,7 @@ process_line (PangoLayout *layout, static void get_items_log_attrs (const char *text, + int start, int length, GList *items, PangoLogAttr *log_attrs, @@ -4096,11 +4097,13 @@ get_items_log_attrs (const char *text, int offset = 0; GList *l; - pango_default_break (text, length, NULL, log_attrs, log_attrs_len); + pango_default_break (text + start, length, NULL, log_attrs, log_attrs_len); for (l = items; l; l = l->next) { PangoItem *item = l->data; + g_assert (item->offset <= start + length); + g_assert (item->length <= (start + length) - item->offset); pango_tailor_break (text + item->offset, item->length, @@ -4371,7 +4374,8 @@ pango_layout_check_lines (PangoLayout *layout) apply_attributes_to_items (state.items, shape_attrs); - get_items_log_attrs (start, + get_items_log_attrs (layout->text, + start - layout->text, delimiter_index + delim_len, state.items, layout->log_attrs + start_offset, |