From 624d1371304a5ae4b3429ad5e4267aac7cd03dfd Mon Sep 17 00:00:00 2001
From: Berke Güzel <wenekar1@gmail.com>
Date: Mon, 12 Oct 2026 00:09:38 +0300
Subject: missing impls and hardening

---
 src/common/backend.c | 57 +++++++++++++++++++++++++++++++++++++++++++---------
 1 file changed, 47 insertions(+), 10 deletions(-)

(limited to 'src/common/backend.c')

diff --git a/src/common/backend.c b/src/common/backend.c
index 2220f1f..214854b 100644
--- a/src/common/backend.c
+++ b/src/common/backend.c
@@ -113,14 +113,18 @@ int yasl_display_modifiers(const struct yasl_display *d)
 
 void yasl_display_copy(struct yasl_display *d, enum yasl_selection sel, const char *text)
 {
-    if (!d || !d->ops->display_copy)
+    if (!d || !d->ops->display_copy || !text ||
+        (sel != YASL_CLIPBOARD && sel != YASL_PRIMARY) ||
+        (sel == YASL_PRIMARY && !(yasl_display_caps(d) & YASL_CAP_PRIMARY_SELECTION)))
         return;
     d->ops->display_copy(d, sel, text);
 }
 
 void yasl_display_paste(struct yasl_display *d, enum yasl_selection sel, struct yasl_surface *target)
 {
-    if (!d || !d->ops->display_paste)
+    if (!d || !d->ops->display_paste ||
+        (sel != YASL_CLIPBOARD && sel != YASL_PRIMARY) ||
+        (sel == YASL_PRIMARY && !(yasl_display_caps(d) & YASL_CAP_PRIMARY_SELECTION)))
         return;
     if (!target || target->display != d)
         return;
@@ -145,8 +149,17 @@ void yasl_display_drag_cancel(struct yasl_display *d)
 
 struct yasl_surface *yasl_surface_create_toplevel(struct yasl_display *d, const struct yasl_surface_spec *spec)
 {
-    if (!d || !d->ops->surface_create_toplevel)
-        return 0;
+    if (!d || !d->ops->surface_create_toplevel || !spec ||
+        spec->size.x <= 0 || spec->size.y <= 0 ||
+        spec->size.x > 32767 || spec->size.y > 32767 ||
+        (int64_t)spec->size.x * spec->size.y * 4 > INT32_MAX) {
+        errno = EINVAL;
+        return NULL;
+    }
+    if (spec->graphics_device && !(yasl_display_caps(d) & YASL_CAP_NATIVE_GRAPHICS)) {
+        errno = ENOTSUP;
+        return NULL;
+    }
     return d->ops->surface_create_toplevel(d, spec);
 }
 
@@ -201,14 +214,34 @@ void yasl_surface_schedule_redraw(struct yasl_surface *s)
 
 bool yasl_surface_present(struct yasl_surface *s, const struct yasl_framebuffer *fb, const struct yasl_damage_list *damage)
 {
-    if (!s || !s->display->ops->surface_present)
-        return 0;
-    return s->display->ops->surface_present(s, fb, damage);
+    if (!s || !s->display->ops->surface_present || !fb || !damage ||
+        !fb->generation || fb->generation != s->frame_generation ||
+        fb->size.x <= 0 || fb->size.y <= 0 ||
+        damage->n < -1 || damage->n > YASL_DAMAGE_MAX)
+        return false;
+    struct yasl_damage_list clipped = {.n = damage->n};
+    if (damage->n >= 0) {
+        clipped.n = 0;
+        for (int i = 0; i < damage->n; i++) {
+            struct yasl_rect2i r = damage->rects[i];
+            if (r.width < 0 || r.height < 0) return false;
+            int64_t right = (int64_t)r.x + r.width;
+            int64_t bottom = (int64_t)r.y + r.height;
+            int64_t x = r.x > 0 ? r.x : 0, y = r.y > 0 ? r.y : 0;
+            if (right > fb->size.x) right = fb->size.x;
+            if (bottom > fb->size.y) bottom = fb->size.y;
+            if (right > x && bottom > y)
+                clipped.rects[clipped.n++] = (struct yasl_rect2i){
+                    (int)x, (int)y, (int)(right - x), (int)(bottom - y),
+                };
+        }
+    }
+    return s->display->ops->surface_present(s, fb, &clipped);
 }
 
 bool yasl_surface_input_poll(struct yasl_surface *s, struct yasl_input_event *ev)
 {
-    if (!s || !s->display->ops->surface_input_poll)
+    if (!s || !ev || !s->display->ops->surface_input_poll)
         return 0;
     return s->display->ops->surface_input_poll(s, ev);
 }
@@ -271,7 +304,7 @@ const char *yasl_surface_ime_preedit(const struct yasl_surface *s)
 
 bool yasl_surface_ime_preedit_cursor(const struct yasl_surface *s, int *begin, int *end)
 {
-    if (!s || !s->display->ops->surface_ime_preedit_cursor)
+    if (!s || !begin || !end || !s->display->ops->surface_ime_preedit_cursor)
         return 0;
     return s->display->ops->surface_ime_preedit_cursor(s, begin, end);
 }
@@ -292,7 +325,11 @@ bool yasl_surface_start_interactive_move(struct yasl_surface *s)
 
 bool yasl_surface_start_interactive_resize(struct yasl_surface *s, enum yasl_resize_edge edge)
 {
-    if (!s || !s->display->ops->surface_start_interactive_resize)
+    if (!s || !s->display->ops->surface_start_interactive_resize ||
+        (edge != YASL_EDGE_TOP && edge != YASL_EDGE_BOTTOM &&
+         edge != YASL_EDGE_LEFT && edge != YASL_EDGE_RIGHT &&
+         edge != YASL_EDGE_TOP_LEFT && edge != YASL_EDGE_TOP_RIGHT &&
+         edge != YASL_EDGE_BOTTOM_LEFT && edge != YASL_EDGE_BOTTOM_RIGHT))
         return 0;
     return s->display->ops->surface_start_interactive_resize(s, edge);
 }
-- 
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