Fix GJDuck#18

GJDuck · GJDuck · commit a72cf7177688 · 2021-07-07T07:18:44.000+08:00
diff --git a/examples/stdlib.c b/examples/stdlib.c
@@ -1291,8 +1291,9 @@ static __attribute__((__noinline__)) void *malloc_allocate(size_t size,
     next += alloc_size;
     if (next > pool->access)
     {
-        size_t access_size =
-          ((next - pool->access) / MALLOC_PAGE_SIZE) + MALLOC_PAGE_SIZE;
+        size_t access_size = ((next - pool->access) / MALLOC_PAGE_SIZE) + 1;
+        access_size = (access_size < 4? 4: access_size);
+        access_size *= MALLOC_PAGE_SIZE;
         if (mprotect(pool->access, access_size, PROT_READ | PROT_WRITE) < 0)
         {
             if (lock)
diff --git a/test/regtest/18.exp b/test/regtest/18.exp
@@ -0,0 +1,2 @@
+buf = "aaaaaaaaaa...", strlen(buf) = 8191
+PASSED
diff --git a/test/regtest/18.in b/test/regtest/18.in
@@ -0,0 +1 @@
+./test.pie -M 'asm=.*%cs:.*' -A 'call bug_18@patch'
diff --git a/test/regtest/patch.cpp b/test/regtest/patch.cpp
@@ -351,3 +351,15 @@ void string(const char *s)
     fprintf(stderr, "%s\n", s);
 }
 
+void bug_18(void)
+{
+    int size = 8192;
+    char *buf = (char *)malloc((size_t) size * sizeof(char));
+
+    for (int i = 0; i < size; i += 1)
+        buf[i] = 'a';
+	buf[size-1] = '\0';
+
+	fprintf(stderr, "buf = \"%.10s...\", strlen(buf) = %zu\n", buf, strlen(buf));
+}
+

Original file line number	Diff line number	Diff line change
`@@ -1291,8 +1291,9 @@ static __attribute__((__noinline__)) void *malloc_allocate(size_t size,`
`1291`	`1291`	`next += alloc_size;`
`1292`	`1292`	`if (next > pool->access)`
`1293`	`1293`	`{`
`1294`		`- size_t access_size =`
`1295`		`- ((next - pool->access) / MALLOC_PAGE_SIZE) + MALLOC_PAGE_SIZE;`
	`1294`	`+ size_t access_size = ((next - pool->access) / MALLOC_PAGE_SIZE) + 1;`
	`1295`	`+ access_size = (access_size < 4? 4: access_size);`
	`1296`	`+ access_size *= MALLOC_PAGE_SIZE;`
`1296`	`1297`	`if (mprotect(pool->access, access_size, PROT_READ \| PROT_WRITE) < 0)`
`1297`	`1298`	`{`
`1298`	`1299`	`if (lock)`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+./test.pie -M 'asm=.%cs:.' -A 'call bug_18@patch'`