diff options
| author | Will Deacon <will.deacon@arm.com> | 2018-02-05 15:34:24 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-20 08:21:08 +0200 |
| commit | 1cd969fdb447655e6f4b1e0a3213e27c7ad236c2 (patch) | |
| tree | 96fab9dba1f2a4a3c73ad8c2b847e66ed6c8f1ed | |
| parent | 82236561095d64471a3a38d3a8f1fd7d815df3dd (diff) | |
arm64: futex: Mask __user pointers prior to dereference
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: Mark Rutland <mark.rutland@arm.com> [v4.9 backport]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/futex.h | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/arch/arm64/include/asm/futex.h b/arch/arm64/include/asm/futex.h index 20dcb196b240..4e5f36a804b4 100644 --- a/arch/arm64/include/asm/futex.h +++ b/arch/arm64/include/asm/futex.h @@ -51,13 +51,14 @@ : "memory") static inline int -futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *uaddr) +futex_atomic_op_inuser(unsigned int encoded_op, u32 __user *_uaddr) { int op = (encoded_op >> 28) & 7; int cmp = (encoded_op >> 24) & 15; int oparg = (int)(encoded_op << 8) >> 20; int cmparg = (int)(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 = 1U << (oparg & 0x1f); @@ -109,15 +110,17 @@ futex_atomic_op_inuser(unsigned 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); asm volatile("// futex_atomic_cmpxchg_inatomic\n" ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_HAS_PAN, CONFIG_ARM64_PAN) " prfm pstl1strm, %2\n" |