diff options
| -rw-r--r-- | include/linux/kprobes.h | 7 | ||||
| -rw-r--r-- | kernel/kprobes.c | 52 |
2 files changed, 59 insertions, 0 deletions
diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h index 0f28486f6360..cd507ab4fed7 100644 --- a/include/linux/kprobes.h +++ b/include/linux/kprobes.h @@ -173,6 +173,13 @@ struct kretprobe_blackpoint { const char *name; void *addr; }; + +struct kprobe_blackpoint { + const char *name; + unsigned long start_addr; + unsigned long range; +}; + extern struct kretprobe_blackpoint kretprobe_blacklist[]; static inline void kretprobe_assert(struct kretprobe_instance *ri, diff --git a/kernel/kprobes.c b/kernel/kprobes.c index fcfb580c3afc..f02a4311768b 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -72,6 +72,18 @@ DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; +/* + * Normally, functions that we'd want to prohibit kprobes in, are marked + * __kprobes. But, there are cases where such functions already belong to + * a different section (__sched for preempt_schedule) + * + * For such cases, we now have a blacklist + */ +struct kprobe_blackpoint kprobe_blacklist[] = { + {"preempt_schedule",}, + {NULL} /* Terminator */ +}; + #ifdef __ARCH_WANT_KPROBES_INSN_SLOT /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -492,9 +504,22 @@ static int __kprobes register_aggr_kprobe(struct kprobe *old_p, static int __kprobes in_kprobes_functions(unsigned long addr) { + struct kprobe_blackpoint *kb; + if (addr >= (unsigned long)__kprobes_text_start && addr < (unsigned long)__kprobes_text_end) return -EINVAL; + /* + * If there exists a kprobe_blacklist, verify and + * fail any probe registration in the prohibited area + */ + for (kb = kprobe_blacklist; kb->name != NULL; kb++) { + if (kb->start_addr) { + if (addr >= kb->start_addr && + addr < (kb->start_addr + kb->range)) + return -EINVAL; + } + } return 0; } @@ -811,6 +836,11 @@ void __kprobes unregister_kretprobe(struct kretprobe *rp) static int __init init_kprobes(void) { int i, err = 0; + unsigned long offset = 0, size = 0; + char *modname, namebuf[128]; + const char *symbol_name; + void *addr; + struct kprobe_blackpoint *kb; /* FIXME allocate the probe table, currently defined statically */ /* initialize all list heads */ @@ -819,6 +849,28 @@ static int __init init_kprobes(void) INIT_HLIST_HEAD(&kretprobe_inst_table[i]); } + /* + * Lookup and populate the kprobe_blacklist. + * + * Unlike the kretprobe blacklist, we'll need to determine + * the range of addresses that belong to the said functions, + * since a kprobe need not necessarily be at the beginning + * of a function. + */ + for (kb = kprobe_blacklist; kb->name != NULL; kb++) { + kprobe_lookup_name(kb->name, addr); + if (!addr) + continue; + + kb->start_addr = (unsigned long)addr; + symbol_name = kallsyms_lookup(kb->start_addr, + &size, &offset, &modname, namebuf); + if (!symbol_name) + kb->range = 0; + else + kb->range = size; + } + if (kretprobe_blacklist_size) { /* lookup the function address from its name */ for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { |