What problem could happen on a write() if the pointer argument is not first verified by...

 

Transcribed Image Text:

What problem could happen on a write() if the pointer argument is not first verified by the kernel to be in user space, and the supplied pointer is a virtual address in kernel space which has a valid mapping to a physical address? Q8.2 5 Points If the buffer pointer passed to read() or write() is not a valid virtual address (ie, in a region of the virtual address space that has not yet been made valid, e.g. with sbrk), the read or write cannot complete. According to the man pages, in this case, they return-1 and set errno to EFAULT. If these system calls did not do this, what could happen on a write() if the pointer argument is an invalid virtual address? [Hint, this question is not about demand allocation.] Activate Wir Go to Settings t What problem could happen on a write() if the pointer argument is not first verified by the kernel to be in user space, and the supplied pointer is a virtual address in kernel space which has a valid mapping to a physical address? Q8.2 5 Points If the buffer pointer passed to read() or write() is not a valid virtual address (ie, in a region of the virtual address space that has not yet been made valid, e.g. with sbrk), the read or write cannot complete. According to the man pages, in this case, they return-1 and set errno to EFAULT. If these system calls did not do this, what could happen on a write() if the pointer argument is an invalid virtual address? [Hint, this question is not about demand allocation.] Activate Wir Go to Settings t

Answer rating: 100% (QA)

If the write system call does not first verify that the pointer argument is in user space and the supplied pointer is a virtual address in kernel spac... View the full answer