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-rw-r--r--kernel/futex.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/kernel/futex.c b/kernel/futex.c
index 80ba086f021d..f6ff0191ecf7 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -251,6 +251,9 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
return -EINVAL;
address -= key->both.offset;
+ if (unlikely(!access_ok(rw, uaddr, sizeof(u32))))
+ return -EFAULT;
+
/*
* PROCESS_PRIVATE futexes are fast.
* As the mm cannot disappear under us and the 'key' only needs
@@ -259,8 +262,6 @@ get_futex_key(u32 __user *uaddr, int fshared, union futex_key *key, int rw)
* but access_ok() should be faster than find_vma()
*/
if (!fshared) {
- if (unlikely(!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))))
- return -EFAULT;
key->private.mm = mm;
key->private.address = address;
get_futex_key_refs(key);
@@ -288,7 +289,7 @@ again:
put_page(page);
/* serialize against __split_huge_page_splitting() */
local_irq_disable();
- if (likely(__get_user_pages_fast(address, 1, 1, &page) == 1)) {
+ if (likely(__get_user_pages_fast(address, 1, !ro, &page) == 1)) {
page_head = compound_head(page);
/*
* page_head is valid pointer but we must pin