fault_in_user_writeable() should verify R/W access but only verify W. In
most archs W implies R, but not true in MIPS and LoongArch, so fix it.
Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
Signed-off-by: Hongchen Zhang <zhanghongchen@xxxxxxxxxxx>
---
kernel/futex.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/kernel/futex.c b/kernel/futex.c
index 2ecb07575055..c3b68be31bf3 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -672,10 +672,15 @@ static int get_futex_key(u32 __user *uaddr, bool fshared, union futex_key *key,
*/
static int fault_in_user_writeable(u32 __user *uaddr)
{
- struct mm_struct *mm = current->mm;
int ret;
+ struct mm_struct *mm = current->mm;
+ struct vm_area_struct *vma;
mmap_read_lock(mm);
+ vma = find_vma(mm, (unsigned long)uaddr);
+ if (!(vma->vm_flags & VM_READ))
+ ret = -EFAULT;
+
ret = fixup_user_fault(mm, (unsigned long)uaddr,
FAULT_FLAG_WRITE, NULL);
mmap_read_unlock(mm);
--
2.27.0
