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x86 futex: fix out of bounds shift

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8 << 28 needs unsigned to fit, other shifts were done to truncate
the input, use a mask instead

Change-Id: I81ba41595f4629f1df554e34392116440ff3b641
This commit is contained in:
Dominique Martinet
2018-07-17 18:49:26 +09:00
committed by Dominique Martinet
parent 6f7c428a34
commit bc887aab44
3 changed files with 6 additions and 5 deletions
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7
arch/x86_64/kernel/include/arch-futex.h
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@@ -64,12 +64,13 @@ static inline int futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval,
return oldval;
}
static inline int futex_atomic_op_inuser(int encoded_op, int __user *uaddr)
static inline int futex_atomic_op_inuser(int encoded_op,
int __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 oparg = (encoded_op & 0x00fff000) >> 12;
int cmparg = encoded_op & 0xfff;
int oldval = 0, ret, tem;
if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))