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authorHelge Deller <deller@gmx.de>2014-05-05 18:07:12 +0200
committerHelge Deller <deller@gmx.de>2014-05-15 21:12:15 +0200
commitfef47e2a2e1e75fe50a10f634a80f16808348cc6 (patch)
treef052abbf816238548d278d20cd8164daa7cd4dcc /arch/parisc/kernel/traps.c
parent455c6fdbd219161bd09b1165f11699d6d73de11c (diff)
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 <deller@gmx.de> Cc: stable@vger.kernel.org # 3.13+
Diffstat (limited to 'arch/parisc/kernel/traps.c')
-rw-r--r--arch/parisc/kernel/traps.c54
1 files changed, 25 insertions, 29 deletions
diff --git a/arch/parisc/kernel/traps.c b/arch/parisc/kernel/traps.c
index 1cd1d0c83b6d..47ee620d15d2 100644
--- a/arch/parisc/kernel/traps.c
+++ b/arch/parisc/kernel/traps.c
@@ -25,6 +25,7 @@
#include <linux/interrupt.h>
#include <linux/console.h>
#include <linux/bug.h>
+#include <linux/ratelimit.h>
#include <asm/assembly.h>
#include <asm/uaccess.h>
@@ -42,9 +43,6 @@
#include "../math-emu/math-emu.h" /* for handle_fpe() */
-#define PRINT_USER_FAULTS /* (turn this on if you want user faults to be */
- /* dumped to the console via printk) */
-
#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK)
DEFINE_SPINLOCK(pa_dbit_lock);
#endif
@@ -160,6 +158,17 @@ void show_regs(struct pt_regs *regs)
}
}
+static DEFINE_RATELIMIT_STATE(_hppa_rs,
+ DEFAULT_RATELIMIT_INTERVAL, DEFAULT_RATELIMIT_BURST);
+
+#define parisc_printk_ratelimited(critical, regs, fmt, ...) { \
+ if ((critical || show_unhandled_signals) && __ratelimit(&_hppa_rs)) { \
+ printk(fmt, ##__VA_ARGS__); \
+ show_regs(regs); \
+ } \
+}
+
+
static void do_show_stack(struct unwind_frame_info *info)
{
int i = 1;
@@ -229,12 +238,10 @@ void die_if_kernel(char *str, struct pt_regs *regs, long err)
if (err == 0)
return; /* STFU */
- printk(KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
+ parisc_printk_ratelimited(1, regs,
+ KERN_CRIT "%s (pid %d): %s (code %ld) at " RFMT "\n",
current->comm, task_pid_nr(current), str, err, regs->iaoq[0]);
-#ifdef PRINT_USER_FAULTS
- /* XXX for debugging only */
- show_regs(regs);
-#endif
+
return;
}
@@ -321,14 +328,11 @@ static void handle_break(struct pt_regs *regs)
(tt == BUG_TRAP_TYPE_NONE) ? 9 : 0);
}
-#ifdef PRINT_USER_FAULTS
- if (unlikely(iir != GDB_BREAK_INSN)) {
- printk(KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
+ if (unlikely(iir != GDB_BREAK_INSN))
+ parisc_printk_ratelimited(0, regs,
+ KERN_DEBUG "break %d,%d: pid=%d command='%s'\n",
iir & 31, (iir>>13) & ((1<<13)-1),
task_pid_nr(current), current->comm);
- show_regs(regs);
- }
-#endif
/* send standard GDB signal */
handle_gdb_break(regs, TRAP_BRKPT);
@@ -758,11 +762,9 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
default:
if (user_mode(regs)) {
-#ifdef PRINT_USER_FAULTS
- printk(KERN_DEBUG "\nhandle_interruption() pid=%d command='%s'\n",
- task_pid_nr(current), current->comm);
- show_regs(regs);
-#endif
+ parisc_printk_ratelimited(0, regs, KERN_DEBUG
+ "handle_interruption() pid=%d command='%s'\n",
+ task_pid_nr(current), current->comm);
/* SIGBUS, for lack of a better one. */
si.si_signo = SIGBUS;
si.si_code = BUS_OBJERR;
@@ -779,16 +781,10 @@ void notrace handle_interruption(int code, struct pt_regs *regs)
if (user_mode(regs)) {
if ((fault_space >> SPACEID_SHIFT) != (regs->sr[7] >> SPACEID_SHIFT)) {
-#ifdef PRINT_USER_FAULTS
- if (fault_space == 0)
- printk(KERN_DEBUG "User Fault on Kernel Space ");
- else
- printk(KERN_DEBUG "User Fault (long pointer) (fault %d) ",
- code);
- printk(KERN_CONT "pid=%d command='%s'\n",
- task_pid_nr(current), current->comm);
- show_regs(regs);
-#endif
+ parisc_printk_ratelimited(0, regs, KERN_DEBUG
+ "User fault %d on space 0x%08lx, pid=%d command='%s'\n",
+ code, fault_space,
+ task_pid_nr(current), current->comm);
si.si_signo = SIGSEGV;
si.si_errno = 0;
si.si_code = SEGV_MAPERR;