From aa51b6bc79078e1b8a168f38926db9d6cb2181b7 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 23 Jun 2021 14:01:35 +0200 Subject: [PATCH] x86/fpu: Limit xstate copy size in xstateregs_set() [ 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 Signed-off-by: Borislav Petkov Reviewed-by: Andy Lutomirski Reviewed-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210623121452.120741557@linutronix.de Signed-off-by: Sasha Levin --- 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 d652b939ccfb..68e1fb66e701 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -124,7 +124,7 @@ 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;