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fix: add check to mmap to ensure file isn't mapped over stack segment (ed1223)

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Themis Demetriades
2024-12-05 17:11:02 +00:00
parent d03e253046
commit 7860f3863f
1 changed files with 4 additions and 0 deletions
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4
src/userprog/syscall.c
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@@ -426,6 +426,10 @@ syscall_mmap (int fd, void *addr)
if (file_size == 0) if (file_size == 0)
return MMAP_FAILURE; return MMAP_FAILURE;
/* Ensure that the mmap page doesn't overlap with the stack. */
if (addr >= (thread_current ()->curr_esp) - PGSIZE)
return MMAP_FAILURE;
/* Check and ensure that there is enough space in the user virtual memory to /* Check and ensure that there is enough space in the user virtual memory to
hold the entire file. */ hold the entire file. */
for (off_t ofs = 0; ofs < file_size; ofs += PGSIZE) for (off_t ofs = 0; ofs < file_size; ofs += PGSIZE)