[PATCH] RLIMIT_MEMLOCK checking fix

Always use page counts when doing RLIMIT_MEMLOCK checking to avoid possible
overflow.

Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/mmap.c b/mm/mmap.c
index 1ec0f6e9c0d86a4f9d523f9f497a0a0ea720a255..01f9793591f666965342df8ef886358680bbae4c 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -937,9 +937,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr,
        /* mlock MCL_FUTURE? */
        if (vm_flags & VM_LOCKED) {
                unsigned long locked, lock_limit;
-               locked = mm->locked_vm << PAGE_SHIFT;
+               locked = len >> PAGE_SHIFT;
+               locked += mm->locked_vm;
                lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
-               locked += len;
+               lock_limit >>= PAGE_SHIFT;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        return -EAGAIN;
        }
@@ -1822,9 +1823,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
         */
        if (mm->def_flags & VM_LOCKED) {
                unsigned long locked, lock_limit;
-               locked = mm->locked_vm << PAGE_SHIFT;
+               locked = len >> PAGE_SHIFT;
+               locked += mm->locked_vm;
                lock_limit = current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur;
-               locked += len;
+               lock_limit >>= PAGE_SHIFT;
                if (locked > lock_limit && !capable(CAP_IPC_LOCK))
                        return -EAGAIN;
        }