Messages in this thread Patch in this message | | | Date | Wed, 23 Jun 2021 14:01:40 +0200 | From | Thomas Gleixner <> | Subject | [patch V4 13/65] x86/fpu: Fail ptrace() requests that try to set invalid MXCSR values |
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From: Andy Lutomirski <luto@kernel.org>
There is no benefit from accepting and silently changing an invalid MXCSR value supplied via ptrace(). Instead, return -EINVAL on invalid input.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> --- V2: New patch. Picked up from Andy. --- arch/x86/kernel/fpu/regset.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -64,8 +64,9 @@ int xfpregs_set(struct task_struct *targ if (ret) return ret; - /* Mask invalid MXCSR bits (for historical reasons). */ - newstate.mxcsr &= mxcsr_feature_mask; + /* Do not allow an invalid MXCSR value. */ + if (newstate.mxcsr & ~mxcsr_feature_mask) + return -EINVAL; fpu__prepare_write(fpu);
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