diff options
Diffstat (limited to 'arch/ia64/kernel/unaligned.c')
| -rw-r--r-- | arch/ia64/kernel/unaligned.c | 31 |
1 files changed, 28 insertions, 3 deletions
diff --git a/arch/ia64/kernel/unaligned.c b/arch/ia64/kernel/unaligned.c index 112913896844..1e357550c776 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()) |