From f56141e3e2d9aabf7e6b89680ab572c2cdbb2a24 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Thu, 12 Feb 2015 15:01:14 -0800 Subject: all arches, signal: move restart_block to struct task_struct If an attacker can cause a controlled kernel stack overflow, overwriting the restart block is a very juicy exploit target. This is because the restart_block is held in the same memory allocation as the kernel stack. Moving the restart block to struct task_struct prevents this exploit by making the restart_block harder to locate. Note that there are other fields in thread_info that are also easy targets, at least on some architectures. It's also a decent simplification, since the restart code is more or less identical on all architectures. [james.hogan@imgtec.com: metag: align thread_info::supervisor_stack] Signed-off-by: Andy Lutomirski Cc: Thomas Gleixner Cc: Al Viro Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Kees Cook Cc: David Miller Acked-by: Richard Weinberger Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Vineet Gupta Cc: Russell King Cc: Catalin Marinas Cc: Will Deacon Cc: Haavard Skinnemoen Cc: Hans-Christian Egtvedt Cc: Steven Miao Cc: Mark Salter Cc: Aurelien Jacquiot Cc: Mikael Starvik Cc: Jesper Nilsson Cc: David Howells Cc: Richard Kuo Cc: "Luck, Tony" Cc: Geert Uytterhoeven Cc: Michal Simek Cc: Ralf Baechle Cc: Jonas Bonn Cc: "James E.J. Bottomley" Cc: Helge Deller Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Acked-by: Michael Ellerman (powerpc) Tested-by: Michael Ellerman (powerpc) Cc: Martin Schwidefsky Cc: Heiko Carstens Cc: Chen Liqin Cc: Lennox Wu Cc: Chris Metcalf Cc: Guan Xuetao Cc: Chris Zankel Cc: Max Filippov Cc: Oleg Nesterov Cc: Guenter Roeck Signed-off-by: James Hogan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/xtensa/kernel/signal.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/xtensa/kernel') diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c index 4612321c73cc..3d733ba16f28 100644 --- a/arch/xtensa/kernel/signal.c +++ b/arch/xtensa/kernel/signal.c @@ -245,7 +245,7 @@ asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3, int ret; /* Always make any pending restarted system calls return -EINTR */ - current_thread_info()->restart_block.fn = do_no_restart_syscall; + current->restart_block.fn = do_no_restart_syscall; if (regs->depc > 64) panic("rt_sigreturn in double exception!\n"); -- cgit v1.2.3 From 62518994dd4c7c9a0a634441f012281406887258 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Fri, 13 Feb 2015 14:37:17 -0800 Subject: xtensa: use %*pb[l] to print bitmaps including cpumasks and nodemasks printk and friends can now format bitmaps using '%*pb[l]'. cpumask and nodemask also provide cpumask_pr_args() and nodemask_pr_args() respectively which can be used to generate the two printf arguments necessary to format the specified cpu/nodemask. Signed-off-by: Tejun Heo Cc: Chris Zankel Cc: Max Filippov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/xtensa/kernel/setup.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'arch/xtensa/kernel') diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c index 06370ccea9e9..28fc57ef5b86 100644 --- a/arch/xtensa/kernel/setup.c +++ b/arch/xtensa/kernel/setup.c @@ -574,12 +574,9 @@ void machine_power_off(void) static int c_show(struct seq_file *f, void *slot) { - char buf[NR_CPUS * 5]; - - cpulist_scnprintf(buf, sizeof(buf), cpu_online_mask); /* high-level stuff */ seq_printf(f, "CPU count\t: %u\n" - "CPU list\t: %s\n" + "CPU list\t: %*pbl\n" "vendor_id\t: Tensilica\n" "model\t\t: Xtensa " XCHAL_HW_VERSION_NAME "\n" "core ID\t\t: " XCHAL_CORE_ID "\n" @@ -588,7 +585,7 @@ c_show(struct seq_file *f, void *slot) "cpu MHz\t\t: %lu.%02lu\n" "bogomips\t: %lu.%02lu\n", num_online_cpus(), - buf, + cpumask_pr_args(cpu_online_mask), XCHAL_BUILD_UNIQUE_ID, XCHAL_HAVE_BE ? "big" : "little", ccount_freq/1000000, -- cgit v1.2.3