Remove the size limit for memory read and write

Eliminate the maximum size restriction for uc_mem_read and uc_mem_write. This
change is required to support applications, such as LLVM CFI, that map or unmap
memory blocks with sizes equal to or greater than INT_MAX.

Author: secretnonempty

uc.c

@@ -565,6 +565,8 @@ static bool check_mem_area(uc_engine *uc, uint64_t address, size_t size)
     return (count == size);
 }
 
+#define MAX_RW_LENGTH ((INT_MAX >> (8*sizeof(int)/2)) << (8*sizeof(int)/2))
+
 UNICORN_EXPORT
 uc_err uc_mem_read(uc_engine *uc, uint64_t address, void *_bytes, size_t size)
 {
@@ -573,10 +575,6 @@ uc_err uc_mem_read(uc_engine *uc, uint64_t address, void *_bytes, size_t size)
 
     UC_INIT(uc);
 
-    // qemu cpu_physical_memory_rw() size is an int
-    if (size > INT_MAX)
-        return UC_ERR_ARG;
-
     if (uc->mem_redirect) {
         address = uc->mem_redirect(address);
     }
@@ -590,6 +588,7 @@ uc_err uc_mem_read(uc_engine *uc, uint64_t address, void *_bytes, size_t size)
         MemoryRegion *mr = memory_mapping(uc, address);
         if (mr) {
             len = (size_t)MIN(size - count, mr->end - address);
+            len = (size_t)MIN(len, MAX_RW_LENGTH);
             if (uc->read_mem(&uc->address_space_memory, address, bytes, len) ==
                 false) {
                 break;
@@ -618,10 +617,6 @@ uc_err uc_mem_write(uc_engine *uc, uint64_t address, const void *_bytes,
 
     UC_INIT(uc);
 
-    // qemu cpu_physical_memory_rw() size is an int
-    if (size > INT_MAX)
-        return UC_ERR_ARG;
-
     if (uc->mem_redirect) {
         address = uc->mem_redirect(address);
     }
@@ -642,6 +637,7 @@ uc_err uc_mem_write(uc_engine *uc, uint64_t address, const void *_bytes,
             }
 
             len = (size_t)MIN(size - count, mr->end - address);
+            len = (size_t)MIN(len, MAX_RW_LENGTH);
             if (uc->write_mem(&uc->address_space_memory, address, bytes, len) ==
                 false) {
                 break;