called pkey_set().
int real_prot = PROT_READ|PROT_WRITE;
- pkey = pkey_alloc(0, PKEY_DENY_WRITE);
+ pkey = pkey_alloc(0, PKEY_DISABLE_WRITE);
ptr = mmap(NULL, PAGE_SIZE, PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
ret = pkey_mprotect(ptr, PAGE_SIZE, real_prot, pkey);
... application runs here
Now, if the application needs to update the data at 'ptr', it can
gain access, do the update, then remove its write access:
- pkey_set(pkey, 0); // clear PKEY_DENY_WRITE
+ pkey_set(pkey, 0); // clear PKEY_DISABLE_WRITE
*ptr = foo; // assign something
- pkey_set(pkey, PKEY_DENY_WRITE); // set PKEY_DENY_WRITE again
+ pkey_set(pkey, PKEY_DISABLE_WRITE); // set PKEY_DISABLE_WRITE again
Now when it frees the memory, it will also free the pkey since it
is no longer in use: