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authorWill Deacon <will.deacon@arm.com>2018-02-05 15:34:24 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-04-20 08:21:08 +0200
commit1cd969fdb447655e6f4b1e0a3213e27c7ad236c2 (patch)
tree96fab9dba1f2a4a3c73ad8c2b847e66ed6c8f1ed /arch/arm64
parent82236561095d64471a3a38d3a8f1fd7d815df3dd (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>
Diffstat (limited to 'arch/arm64')
-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 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"