From fef47e2a2e1e75fe50a10f634a80f16808348cc6 Mon Sep 17 00:00:00 2001 From: Helge Deller Date: Mon, 5 May 2014 18:07:12 +0200 Subject: parisc: ratelimit userspace segfault printing Ratelimit printing of userspace segfaults and make it runtime configurable via the /proc/sys/debug/exception-trace variable. This should resolve syslog from growing way too fast and thus prevents possible system service attacks. Signed-off-by: Helge Deller Cc: stable@vger.kernel.org # 3.13+ --- arch/parisc/mm/fault.c | 44 ++++++++++++++++++++++++++++++-------------- 1 file changed, 30 insertions(+), 14 deletions(-) (limited to 'arch/parisc/mm') diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index 9d08c71a967e..d72197f0ddb8 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -19,10 +19,6 @@ #include #include -#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */ - /* dumped to the console via printk) */ - - /* Various important other fields */ #define bit22set(x) (x & 0x00000200) #define bits23_25set(x) (x & 0x000001c0) @@ -34,6 +30,8 @@ DEFINE_PER_CPU(struct exception_data, exception_data); +int show_unhandled_signals = 1; + /* * parisc_acctyp(unsigned int inst) -- * Given a PA-RISC memory access instruction, determine if the @@ -173,6 +171,32 @@ int fixup_exception(struct pt_regs *regs) return 0; } +/* + * Print out info about fatal segfaults, if the show_unhandled_signals + * sysctl is set: + */ +static inline void +show_signal_msg(struct pt_regs *regs, unsigned long code, + unsigned long address, struct task_struct *tsk, + struct vm_area_struct *vma) +{ + if (!unhandled_signal(tsk, SIGSEGV)) + return; + + if (!printk_ratelimit()) + return; + + pr_warn("\n"); + pr_warn("do_page_fault() command='%s' type=%lu address=0x%08lx", + tsk->comm, code, address); + print_vma_addr(KERN_CONT " in ", regs->iaoq[0]); + if (vma) + pr_warn(" vm_start = 0x%08lx, vm_end = 0x%08lx\n", + vma->vm_start, vma->vm_end); + + show_regs(regs); +} + void do_page_fault(struct pt_regs *regs, unsigned long code, unsigned long address) { @@ -270,16 +294,8 @@ bad_area: if (user_mode(regs)) { struct siginfo si; -#ifdef PRINT_USER_FAULTS - printk(KERN_DEBUG "\n"); - printk(KERN_DEBUG "do_page_fault() pid=%d command='%s' type=%lu address=0x%08lx\n", - task_pid_nr(tsk), tsk->comm, code, address); - if (vma) { - printk(KERN_DEBUG "vm_start = 0x%08lx, vm_end = 0x%08lx\n", - vma->vm_start, vma->vm_end); - } - show_regs(regs); -#endif + show_signal_msg(regs, code, address, tsk, vma); + switch (code) { case 15: /* Data TLB miss fault/Data page fault */ /* send SIGSEGV when outside of vma */ -- cgit v1.2.3