Commit aa51b6bc authored Jun 23, 2021 by Thomas Gleixner Committed by Greg Kroah-Hartman Jul 20, 2021

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: 91c3dba7 ("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>

parent df749be3

arch/x86/kernel/fpu/regset.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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;