Vineet Gupta e4140819da ARC: signal handling robustify ... A malicious signal handler / restorer can DOS the system by fudging the user regs saved on stack, causing weird things such as sigreturn returning to user mode PC but cpu state still being kernel mode.... Ensure that in sigreturn path status32 always has U bit; any other bogosity (gargbage PC etc) will be taken care of by normal user mode exceptions mechanisms. Reproducer signal handler: void handle_sig(int signo, siginfo_t *info, void *context) { ucontext_t *uc = context; struct user_regs_struct *regs = &(uc->uc_mcontext.regs); regs->scratch.status32 = 0; } Before the fix, kernel would go off to weeds like below: --------->8----------- [ARCLinux]$ ./signal-test Path: /signal-test CPU: 0 PID: 61 Comm: signal-test Not tainted 4.0.0-rc5+ #65 task: 8f177880 ti: 5ffe6000 task.ti: 8f15c000 [ECR ]: 0x00220200 => Invalid Write @ 0x00000010 by insn @ 0x00010698 [EFA ]: 0x00000010 [BLINK ]: 0x2007c1ee [ERET ]: 0x10698 [STAT32]: 0x00000000 : <-------- BTA: 0x00010680 SP: 0x5ffe7e48 FP: 0x00000000 LPS: 0x20003c6c LPE: 0x20003c70 LPC: 0x00000000 ... --------->8----------- Reported-by: Alexey Brodkin <abrodkin@synopsys.com> Cc: <stable@vger.kernel.org> Signed-off-by: Vineet Gupta <vgupta@synopsys.com>		2015-03-26 11:19:36 +05:30
..
boot	dmaengine: dw: define DW_DMA_MAX_NR_MASTERS	2015-02-04 22:39:44 -08:00
configs	ARC: rename default defconfig	2014-12-17 15:23:56 +05:30
include	ARC: Fix thread_saved_pc()	2015-02-27 10:59:34 +05:30
kernel	ARC: signal handling robustify	2015-03-26 11:19:36 +05:30
lib
mm	ARC: perf: Enable generic software events	2015-02-27 10:15:01 +05:30
oprofile
plat-arcfpga
plat-tb10x
Kbuild
Kconfig	ARC: add power management options	2014-11-03 18:05:43 +05:30
Kconfig.debug
Makefile	ARC: rename default defconfig	2014-12-17 15:23:56 +05:30