4.15-stable review patch. If anyone has any objections, please let me know.
------------------ From: Will Deacon <[email protected]> Commit 91b2d3442f6a upstream. The arm64 futex code has some explicit dereferencing of user pointers where performing atomic operations in response to a futex command. This patch uses masking to limit any speculative futex operations to within the user address space. Signed-off-by: Will Deacon <[email protected]> Signed-off-by: Catalin Marinas <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/arm64/include/asm/futex.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -48,9 +48,10 @@ do { \ } while (0) static inline int -arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *uaddr) +arch_futex_atomic_op_inuser(int op, int oparg, int *oval, u32 __user *_uaddr) { int oldval = 0, ret, tmp; + u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); pagefault_disable(); @@ -88,15 +89,17 @@ arch_futex_atomic_op_inuser(int op, int } static inline int -futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, +futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *_uaddr, u32 oldval, u32 newval) { int ret = 0; u32 val, tmp; + u32 __user *uaddr; - if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32))) + if (!access_ok(VERIFY_WRITE, _uaddr, sizeof(u32))) return -EFAULT; + uaddr = __uaccess_mask_ptr(_uaddr); uaccess_enable(); asm volatile("// futex_atomic_cmpxchg_inatomic\n" " prfm pstl1strm, %2\n"
