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authorWill Deacon <will.deacon@arm.com>2018-02-05 15:34:24 +0000
committerCatalin Marinas <catalin.marinas@arm.com>2018-02-06 22:53:42 +0000
commit91b2d3442f6a44dce875670d702af22737ad5eff (patch)
treeb723651d1d77cee6e73d4d1a1898653f0801d6d4 /arch
parentf71c2ffcb20dd8626880747557014bb9a61eb90e (diff)
arm64: futex: Mask __user pointers prior to dereference
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>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/futex.h9
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h
index 5bb2fd4674e7..07fe2479d310 100644
--- 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 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);
uaccess_enable();
asm volatile("// futex_atomic_cmpxchg_inatomic\n"
" prfm pstl1strm, %2\n"