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: Alex Shi <[email protected]> Conflicts: change on old futex_atomic_op_inuser function instead of arch_futex_atomic_op_inuser in arch/arm64/include/asm/futex.h --- arch/arm64/include/asm/futex.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 85c4a89..1943cf6 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -48,13 +48,14 @@ do { \ } while (0) static inline int -futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) +futex_atomic_op_inuser (int encoded_op, u32 __user *_uaddr) { int op = (encoded_op >> 28) & 7; int cmp = (encoded_op >> 24) & 15; int oparg = (encoded_op << 8) >> 20; int cmparg = (encoded_op << 20) >> 20; int oldval = 0, ret, tmp; + u32 __user *uaddr = __uaccess_mask_ptr(_uaddr); if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28)) oparg = 1 << oparg; @@ -106,15 +107,17 @@ futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr) } 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" -- 2.7.4
