From: Thomas Gleixner tglx@linutronix.de
stable inclusion from linux-4.19.198 commit fecb9b7b06ee288103f0f687b57cb033c96c54ca
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[ Upstream commit 07d6688b22e09be465652cf2da0da6bf86154df6 ]
If the count argument is larger than the xstate size, this will happily copy beyond the end of xstate.
Fixes: 91c3dba7dbc1 ("x86/fpu/xstate: Fix PTRACE frames for XSAVES") Signed-off-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Borislav Petkov bp@suse.de Reviewed-by: Andy Lutomirski luto@kernel.org Reviewed-by: Borislav Petkov bp@suse.de Link: https://lkml.kernel.org/r/20210623121452.120741557@linutronix.de Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- arch/x86/kernel/fpu/regset.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index bc02f5144b958..621d249ded0b9 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -128,7 +128,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, /* * A whole standard-format XSAVE buffer is needed: */ - if ((pos != 0) || (count < fpu_user_xstate_size)) + if (pos != 0 || count != fpu_user_xstate_size) return -EFAULT;
xsave = &fpu->state.xsave;