Commit f0cbc8b3 authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Borislav Petkov
Browse files

x86/fpu: Do not leak fpstate pointer on fork 



If fork fails early then the copied task struct would carry the fpstate
pointer of the parent task.

Not a problem right now, but later when dynamically allocated buffers
are available, keeping the pointer might result in freeing the
parent's buffer. Set it to NULL which prevents that. If fork reaches
clone_thread(), the pointer will be correctly set to the new task
context.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211013145322.817101108@linutronix.de
parent 2f27b503

arch/x86/kernel/process.c

+2 −0
Original line number Diff line number Diff line
@@ -87,6 +87,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 
#ifdef CONFIG_VM86

	dst->thread.vm86 = NULL;

#endif

	/* Drop the copied pointer to current's fpstate */

	dst->thread.fpu.fpstate = NULL;

	return 0;

}