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x86/process: Don't mix user/kernel regs in 64bit __show_regs()

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When the kernel.print-fatal-signals sysctl has been enabled, a simple
userspace crash will cause the kernel to write a crash dump that contains,
among other things, the kernel gsbase into dmesg.

As suggested by Andy, limit output to pt_regs, FS_BASE and KERNEL_GS_BASE
in this case.

This also moves the bitness-specific logic from show_regs() into
process_{32,64}.c.

Fixes: 45807a1df9 ("vdso: print fatal signals")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180831194151.123586-1-jannh@google.com
This commit is contained in:
Jann Horn
2018-08-31 21:41:51 +02:00
committed by Thomas Gleixner
parent 17f6bac224
commit 9fe6299dde
4 changed files with 26 additions and 13 deletions
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12
arch/x86/include/asm/kdebug.h
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@@ -22,10 +22,20 @@ enum die_val {
DIE_NMIUNKNOWN,
};
enum show_regs_mode {
SHOW_REGS_SHORT,
/*
* For when userspace crashed, but we don't think it's our fault, and
* therefore don't print kernel registers.
*/
SHOW_REGS_USER,
SHOW_REGS_ALL
};
extern void die(const char *, struct pt_regs *,long);
extern int __must_check __die(const char *, struct pt_regs *, long);
extern void show_stack_regs(struct pt_regs *regs);
extern void __show_regs(struct pt_regs *regs, int all);
extern void __show_regs(struct pt_regs *regs, enum show_regs_mode);
extern void show_iret_regs(struct pt_regs *regs);
extern unsigned long oops_begin(void);
extern void oops_end(unsigned long, struct pt_regs *, int signr);