From: Will Deacon will.deacon@arm.com
commit 91b2d3442f6a44dce875670d702af22737ad5eff 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 will.deacon@arm.com Signed-off-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org --- 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 34d4d2e2f561..8ab6e83cb629 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -53,9 +53,10 @@ : "memory")
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();
@@ -93,15 +94,17 @@ arch_futex_atomic_op_inuser(int op, int oparg, int *oval, 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); asm volatile("// futex_atomic_cmpxchg_inatomic\n" ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, CONFIG_ARM64_PAN) " prfm pstl1strm, %2\n"