[lkml]   [2002]   [Aug]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [TRIVIAL] Warn users about machines with non-working WP bit
Kasper Dupont wrote:

>I just get another idea, that might be easier to get right. If
>the only problem is one process changing the mm while another
>process is doing a copy_to_user, we should be able to fix it by
>placing a readlock on the mm while the copy_to_user is in progress.
Yes, that would work. copy_to_user is never called with the mmap
semaphore locked, i.e.

#define copy_to_user(...) \
down(&current->mm->mmap_sem); \
check_wp_bit(); \
real_copy_to_user(); \

verify_area would just check that the pointer is below TASK_SIZE, and
the wp bit is checked within copy_to_user().

But how many 80386 Linux systems that run the 2.4 kernel exist?


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:22    [W:0.068 / U:1.532 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site