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/proc/*/environ: wrong placing of ptrace_may_attach() check 

It's a bit dopey-looking and can permit a task to cause a pagefault in an mm
which it doesn't have permission to read from.

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Alexey Dobriyan 2007-07-15 23:40:21 -07:00 committed by Linus Torvalds
parent 7126dd0562
commit da58a16173
1 changed files with 8 additions and 3 deletions
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11
fs/proc/base.c
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@ -204,12 +204,17 @@ static int proc_pid_environ(struct task_struct *task, char * buffer)
int res = 0;
struct mm_struct *mm = get_task_mm(task);
if (mm) {
unsigned int len = mm->env_end - mm->env_start;
unsigned int len;
res = -ESRCH;
if (!ptrace_may_attach(task))
goto out;
len = mm->env_end - mm->env_start;
if (len > PAGE_SIZE)
len = PAGE_SIZE;
res = access_process_vm(task, mm->env_start, buffer, len, 0);
if (!ptrace_may_attach(task))
res = -ESRCH;
out:
mmput(mm);
}
return res;