diff options
| -rw-r--r-- | arch/ia64/kernel/unaligned.c | 31 | ||||
| -rw-r--r-- | include/linux/sysctl.h | 1 | ||||
| -rw-r--r-- | kernel/sysctl.c | 14 |
3 files changed, 43 insertions, 3 deletions
diff --git a/arch/ia64/kernel/unaligned.c b/arch/ia64/kernel/unaligned.c index 11291389684..1e357550c77 100644 --- a/arch/ia64/kernel/unaligned.c +++ b/arch/ia64/kernel/unaligned.c @@ -53,6 +53,15 @@ dump (const char *str, void *vp, size_t len) #define SIGN_EXT9 0xffffffffffffff00ul /* + * sysctl settable hook which tells the kernel whether to honor the + * IA64_THREAD_UAC_NOPRINT prctl. Because this is user settable, we want + * to allow the super user to enable/disable this for security reasons + * (i.e. don't allow attacker to fill up logs with unaligned accesses). + */ +int no_unaligned_warning; +static int noprint_warning; + +/* * For M-unit: * * opcode | m | x6 | @@ -1324,8 +1333,9 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs) if ((current->thread.flags & IA64_THREAD_UAC_SIGBUS) != 0) goto force_sigbus; - if (!(current->thread.flags & IA64_THREAD_UAC_NOPRINT) - && within_logging_rate_limit()) + if (!no_unaligned_warning && + !(current->thread.flags & IA64_THREAD_UAC_NOPRINT) && + within_logging_rate_limit()) { char buf[200]; /* comm[] is at most 16 bytes... */ size_t len; @@ -1340,7 +1350,22 @@ ia64_handle_unaligned (unsigned long ifa, struct pt_regs *regs) if (user_mode(regs)) tty_write_message(current->signal->tty, buf); buf[len-1] = '\0'; /* drop '\r' */ - printk(KERN_WARNING "%s", buf); /* watch for command names containing %s */ + /* watch for command names containing %s */ + printk(KERN_WARNING "%s", buf); + } else { + if (no_unaligned_warning && !noprint_warning) { + noprint_warning = 1; + printk(KERN_WARNING "%s(%d) encountered an " + "unaligned exception which required\n" + "kernel assistance, which degrades " + "the performance of the application.\n" + "Unaligned exception warnings have " + "been disabled by the system " + "administrator\n" + "echo 0 > /proc/sys/kernel/ignore-" + "unaligned-usertrap to re-enable\n", + current->comm, current->pid); + } } } else { if (within_logging_rate_limit()) diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h index 0e92bf7ec28..bac61db2645 100644 --- a/include/linux/sysctl.h +++ b/include/linux/sysctl.h @@ -147,6 +147,7 @@ enum KERN_SETUID_DUMPABLE=69, /* int: behaviour of dumps for setuid core */ KERN_SPIN_RETRY=70, /* int: number of spinlock retries */ KERN_ACPI_VIDEO_FLAGS=71, /* int: flags for setting up video after ACPI sleep */ + KERN_IA64_UNALIGNED=72, /* int: ia64 unaligned userland trap enable */ }; diff --git a/kernel/sysctl.c b/kernel/sysctl.c index c05a2b7125e..acf6c1550f2 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -124,6 +124,10 @@ extern int sysctl_hz_timer; extern int acct_parm[]; #endif +#ifdef CONFIG_IA64 +extern int no_unaligned_warning; +#endif + static int parse_table(int __user *, int, void __user *, size_t __user *, void __user *, size_t, ctl_table *, void **); static int proc_doutsstring(ctl_table *table, int write, struct file *filp, @@ -666,6 +670,16 @@ static ctl_table kern_table[] = { .proc_handler = &proc_dointvec, }, #endif +#ifdef CONFIG_IA64 + { + .ctl_name = KERN_IA64_UNALIGNED, + .procname = "ignore-unaligned-usertrap", + .data = &no_unaligned_warning, + .maxlen = sizeof (int), + .mode = 0644, + .proc_handler = &proc_dointvec, + }, +#endif { .ctl_name = 0 } }; |