X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fkprobes.c;h=e3a5d817ac9b0f07b514587a7ec03453461ab655;hb=259d4e41f3ec25f22169daece42729f597b89f9a;hp=f58f171bd65fe36917854cd5755e6f224f1a7747;hpb=4c4308cb93450989846ac49faeb6dab943e7657e;p=linux-2.6 diff --git a/kernel/kprobes.c b/kernel/kprobes.c index f58f171bd6..e3a5d817ac 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -43,9 +43,11 @@ #include #include #include + #include #include #include +#include #define KPROBE_HASH_BITS 6 #define KPROBE_TABLE_SIZE (1 << KPROBE_HASH_BITS) @@ -62,17 +64,14 @@ static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; -static atomic_t kprobe_count; + +/* NOTE: change this value only with kprobe_mutex held */ +static bool kprobe_enabled; DEFINE_MUTEX(kprobe_mutex); /* Protects kprobe_table */ DEFINE_SPINLOCK(kretprobe_lock); /* Protects kretprobe_inst_table */ static DEFINE_PER_CPU(struct kprobe *, kprobe_instance) = NULL; -static struct notifier_block kprobe_page_fault_nb = { - .notifier_call = kprobe_exceptions_notify, - .priority = 0x7fffffff /* we need to notified first */ -}; - #ifdef __ARCH_WANT_KPROBES_INSN_SLOT /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -551,8 +550,6 @@ static int __kprobes __register_kprobe(struct kprobe *p, old_p = get_kprobe(p->addr); if (old_p) { ret = register_aggr_kprobe(old_p, p); - if (!ret) - atomic_inc(&kprobe_count); goto out; } @@ -564,11 +561,8 @@ static int __kprobes __register_kprobe(struct kprobe *p, hlist_add_head_rcu(&p->hlist, &kprobe_table[hash_ptr(p->addr, KPROBE_HASH_BITS)]); - if (atomic_add_return(1, &kprobe_count) == \ - (ARCH_INACTIVE_KPROBE_COUNT + 1)) - register_page_fault_notifier(&kprobe_page_fault_nb); - - arch_arm_kprobe(p); + if (kprobe_enabled) + arch_arm_kprobe(p); out: mutex_unlock(&kprobe_mutex); @@ -607,8 +601,13 @@ valid_p: if (old_p == p || (old_p->pre_handler == aggr_pre_handler && p->list.next == &old_p->list && p->list.prev == &old_p->list)) { - /* Only probe on the hash list */ - arch_disarm_kprobe(p); + /* + * Only probe on the hash list. Disarm only if kprobes are + * enabled - otherwise, the breakpoint would already have + * been removed. We save on flushing icache. + */ + if (kprobe_enabled) + arch_disarm_kprobe(p); hlist_del_rcu(&old_p->hlist); cleanup_p = 1; } else { @@ -647,16 +646,6 @@ valid_p: } mutex_unlock(&kprobe_mutex); } - - /* Call unregister_page_fault_notifier() - * if no probes are active - */ - mutex_lock(&kprobe_mutex); - if (atomic_add_return(-1, &kprobe_count) == \ - ARCH_INACTIVE_KPROBE_COUNT) - unregister_page_fault_notifier(&kprobe_page_fault_nb); - mutex_unlock(&kprobe_mutex); - return; } static struct notifier_block kprobe_exceptions_nb = { @@ -664,9 +653,18 @@ static struct notifier_block kprobe_exceptions_nb = { .priority = 0x7fffffff /* we need to be notified first */ }; +unsigned long __weak arch_deref_entry_point(void *entry) +{ + return (unsigned long)entry; +} int __kprobes register_jprobe(struct jprobe *jp) { + unsigned long addr = arch_deref_entry_point(jp->entry); + + if (!kernel_text_address(addr)) + return -EINVAL; + /* Todo: Verify probepoint is a function entry point */ jp->kp.pre_handler = setjmp_pre_handler; jp->kp.break_handler = longjmp_break_handler; @@ -718,6 +716,18 @@ int __kprobes register_kretprobe(struct kretprobe *rp) int ret = 0; struct kretprobe_instance *inst; int i; + void *addr = rp->kp.addr; + + if (kretprobe_blacklist_size) { + if (addr == NULL) + kprobe_lookup_name(rp->kp.symbol_name, addr); + addr += rp->kp.offset; + + for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { + if (kretprobe_blacklist[i].addr == addr) + return -EINVAL; + } + } rp->kp.pre_handler = pre_handler_kretprobe; rp->kp.post_handler = NULL; @@ -795,7 +805,20 @@ static int __init init_kprobes(void) INIT_HLIST_HEAD(&kprobe_table[i]); INIT_HLIST_HEAD(&kretprobe_inst_table[i]); } - atomic_set(&kprobe_count, 0); + + if (kretprobe_blacklist_size) { + /* lookup the function address from its name */ + for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { + kprobe_lookup_name(kretprobe_blacklist[i].name, + kretprobe_blacklist[i].addr); + if (!kretprobe_blacklist[i].addr) + printk("kretprobe: lookup failed: %s\n", + kretprobe_blacklist[i].name); + } + } + + /* By default, kprobes are enabled */ + kprobe_enabled = true; err = arch_init_kprobes(); if (!err) @@ -806,7 +829,7 @@ static int __init init_kprobes(void) #ifdef CONFIG_DEBUG_FS static void __kprobes report_probe(struct seq_file *pi, struct kprobe *p, - const char *sym, int offset,char *modname) + const char *sym, int offset,char *modname) { char *kprobe_type; @@ -885,9 +908,120 @@ static struct file_operations debugfs_kprobes_operations = { .release = seq_release, }; +static void __kprobes enable_all_kprobes(void) +{ + struct hlist_head *head; + struct hlist_node *node; + struct kprobe *p; + unsigned int i; + + mutex_lock(&kprobe_mutex); + + /* If kprobes are already enabled, just return */ + if (kprobe_enabled) + goto already_enabled; + + for (i = 0; i < KPROBE_TABLE_SIZE; i++) { + head = &kprobe_table[i]; + hlist_for_each_entry_rcu(p, node, head, hlist) + arch_arm_kprobe(p); + } + + kprobe_enabled = true; + printk(KERN_INFO "Kprobes globally enabled\n"); + +already_enabled: + mutex_unlock(&kprobe_mutex); + return; +} + +static void __kprobes disable_all_kprobes(void) +{ + struct hlist_head *head; + struct hlist_node *node; + struct kprobe *p; + unsigned int i; + + mutex_lock(&kprobe_mutex); + + /* If kprobes are already disabled, just return */ + if (!kprobe_enabled) + goto already_disabled; + + kprobe_enabled = false; + printk(KERN_INFO "Kprobes globally disabled\n"); + for (i = 0; i < KPROBE_TABLE_SIZE; i++) { + head = &kprobe_table[i]; + hlist_for_each_entry_rcu(p, node, head, hlist) { + if (!arch_trampoline_kprobe(p)) + arch_disarm_kprobe(p); + } + } + + mutex_unlock(&kprobe_mutex); + /* Allow all currently running kprobes to complete */ + synchronize_sched(); + return; + +already_disabled: + mutex_unlock(&kprobe_mutex); + return; +} + +/* + * XXX: The debugfs bool file interface doesn't allow for callbacks + * when the bool state is switched. We can reuse that facility when + * available + */ +static ssize_t read_enabled_file_bool(struct file *file, + char __user *user_buf, size_t count, loff_t *ppos) +{ + char buf[3]; + + if (kprobe_enabled) + buf[0] = '1'; + else + buf[0] = '0'; + buf[1] = '\n'; + buf[2] = 0x00; + return simple_read_from_buffer(user_buf, count, ppos, buf, 2); +} + +static ssize_t write_enabled_file_bool(struct file *file, + const char __user *user_buf, size_t count, loff_t *ppos) +{ + char buf[32]; + int buf_size; + + buf_size = min(count, (sizeof(buf)-1)); + if (copy_from_user(buf, user_buf, buf_size)) + return -EFAULT; + + switch (buf[0]) { + case 'y': + case 'Y': + case '1': + enable_all_kprobes(); + break; + case 'n': + case 'N': + case '0': + disable_all_kprobes(); + break; + } + + return count; +} + +static struct file_operations fops_kp = { + .read = read_enabled_file_bool, + .write = write_enabled_file_bool, +}; + static int __kprobes debugfs_kprobe_init(void) { struct dentry *dir, *file; + unsigned int value = 1; dir = debugfs_create_dir("kprobes", NULL); if (!dir) @@ -900,6 +1034,13 @@ static int __kprobes debugfs_kprobe_init(void) return -ENOMEM; } + file = debugfs_create_file("enabled", 0600, dir, + &value, &fops_kp); + if (!file) { + debugfs_remove(dir); + return -ENOMEM; + } + return 0; } @@ -912,6 +1053,11 @@ EXPORT_SYMBOL_GPL(register_kprobe); EXPORT_SYMBOL_GPL(unregister_kprobe); EXPORT_SYMBOL_GPL(register_jprobe); EXPORT_SYMBOL_GPL(unregister_jprobe); +#ifdef CONFIG_KPROBES EXPORT_SYMBOL_GPL(jprobe_return); +#endif + +#ifdef CONFIG_KPROBES EXPORT_SYMBOL_GPL(register_kretprobe); EXPORT_SYMBOL_GPL(unregister_kretprobe); +#endif