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Update validate_user_pointer to perform no memory checks when size is 0

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sBubshait
2024-11-04 00:38:58 +00:00
parent e718159ed8
commit 3a258cf064
1 changed files with 6 additions and 2 deletions
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8
src/userprog/syscall.c
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@@ -80,11 +80,15 @@ exit (int status UNUSED)
} }
/* Validates if a block of memory starting at PTR and of size SIZE bytes is /* Validates if a block of memory starting at PTR and of size SIZE bytes is
fully contained within user virtual memory. */ fully contained within user virtual memory. Kills the thread (by calling
thread_exit) if the memory is invalid. Otherwise, returns the PTR given.
If the size is 0, the function does no checks and returns PTR.*/
static void * static void *
validate_user_pointer (void *ptr, size_t size) validate_user_pointer (void *ptr, size_t size)
{ {
if (ptr == NULL || !is_user_vaddr (ptr) || !is_user_vaddr (ptr + size - 1)) if (size > 0 && (ptr == NULL ||
!is_user_vaddr (ptr) ||
!is_user_vaddr (ptr + size - 1)))
thread_exit (); thread_exit ();
return ptr; return ptr;