From 3a8dcfa8b8ee6311cc6426e12580cfd179d3eb1d Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Tue, 17 Jun 2025 10:34:01 +0200
Subject: forbid too long arrays & strings

---
 pez.c | 19 +++++++++++++++++--
 pez.h |  1 +
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/pez.c b/pez.c
index f341c78..72272ca 100644
--- a/pez.c
+++ b/pez.c
@@ -500,6 +500,8 @@ splittable64(uint64_t x)
 /* Objects */
 /***********/
 
+#define FX_MAX_INT 0x7FFFF
+
 static Proto *
 newproto(PezContext *cx, const char *file, const char *name, int line)
 {
@@ -738,6 +740,10 @@ box_str(PezContext *cx, Val *pv, const char *s, int len)
         pv->r = r;
         return 1;
     }
+    if (len > FX_MAX_INT) {
+        cx->err = PEZ_ETooBig;
+        return 0;
+    }
     TRY(slot = strpool_lookup(cx, s, len));
     if (!*slot) {
         Str *o = newobj(cx, PEZ_TString, sizeof(Str) + len + 1);
@@ -762,10 +768,14 @@ sizeofstr(Str *str)
 static Array *
 newarr(PezContext *cx, uint cap)
 {
-    Array *arr = newobj(cx, PEZ_TArray, sizeof *arr);
-    if (!arr) {
+    Array *arr;
+    if (cap > FX_MAX_INT) {
+        cx->err = PEZ_ETooBig;
         return NULL;
     }
+    arr = newobj(cx, PEZ_TArray, sizeof *arr);
+    if (!arr)
+        return NULL;
     if (cap) {
         if (!push(cx, box_obj(arr))) { // gc keep
             cxfree(cx, arr, sizeof *arr);
@@ -785,6 +795,10 @@ arrpushn(PezContext *cx, Array *arr, Val *src, uint n)
         if (cx->gccanrun && (cx->dbg & DBGstressgc)) {
             gc(cx);
         }
+        if (arr->len + n > FX_MAX_INT) {
+            cx->err = PEZ_ETooBig;
+            return 0;
+        }
         if (arr->len + n - 1 >= arr->cap) {
             uint newcap = (arr->len + n - 1) * 2;
             Val *new;
@@ -4455,6 +4469,7 @@ pez_geterr(PezContext *cx)
     case PEZ_ENoMem:   return "out of memory";
     case PEZ_ESyntax:  return cx->errstr;
     case PEZ_ERuntime: return cx->errstr;
+    case PEZ_ETooBig:  return "object too big";
     }
     return NULL;
 }
diff --git a/pez.h b/pez.h
index 62946d2..b27ff4f 100644
--- a/pez.h
+++ b/pez.h
@@ -28,6 +28,7 @@ typedef enum PezError {
     PEZ_ENoMem,
     PEZ_ESyntax,
     PEZ_ERuntime,
+    PEZ_ETooBig,
 } PezError;
 
 typedef struct PezContext PezContext;
-- 
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