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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2014-04-17 17:17:05 +0900
committerIngo Molnar <mingo@kernel.org>2014-04-24 10:02:56 +0200
commit376e242429bf8539ef39a080ac113c8799840b13 (patch)
tree33c871f48d37acd167de0b3bf5c902ce4aaa325c /kernel/kprobes.c
parentbe8f274323c26ddc7e6fd6c44254b7abcdbe6389 (diff)
downloadlwn-376e242429bf8539ef39a080ac113c8799840b13.tar.gz
lwn-376e242429bf8539ef39a080ac113c8799840b13.zip
kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist
Introduce NOKPROBE_SYMBOL() macro which builds a kprobes blacklist at kernel build time. The usage of this macro is similar to EXPORT_SYMBOL(), placed after the function definition: NOKPROBE_SYMBOL(function); Since this macro will inhibit inlining of static/inline functions, this patch also introduces a nokprobe_inline macro for static/inline functions. In this case, we must use NOKPROBE_SYMBOL() for the inline function caller. When CONFIG_KPROBES=y, the macro stores the given function address in the "_kprobe_blacklist" section. Since the data structures are not fully initialized by the macro (because there is no "size" information), those are re-initialized at boot time by using kallsyms. Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Link: http://lkml.kernel.org/r/20140417081705.26341.96719.stgit@ltc230.yrl.intra.hitachi.co.jp Cc: Alok Kataria <akataria@vmware.com> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Christopher Li <sparse@chrisli.org> Cc: Chris Wright <chrisw@sous-sol.org> Cc: David S. Miller <davem@davemloft.net> Cc: Jan-Simon Möller <dl9pf@gmx.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: linux-arch@vger.kernel.org Cc: linux-doc@vger.kernel.org Cc: linux-sparse@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/kprobes.c')
-rw-r--r--kernel/kprobes.c100
1 files changed, 52 insertions, 48 deletions
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 5b5ac76671e7..5ffc6875d2a7 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -86,18 +86,8 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
return &(kretprobe_table_locks[hash].lock);
}
-/*
- * 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
- */
-static struct kprobe_blackpoint kprobe_blacklist[] = {
- {"preempt_schedule",},
- {"native_get_debugreg",},
- {NULL} /* Terminator */
-};
+/* Blacklist -- list of struct kprobe_blacklist_entry */
+static LIST_HEAD(kprobe_blacklist);
#ifdef __ARCH_WANT_KPROBES_INSN_SLOT
/*
@@ -1328,24 +1318,22 @@ bool __weak arch_within_kprobe_blacklist(unsigned long addr)
addr < (unsigned long)__kprobes_text_end;
}
-static int __kprobes in_kprobes_functions(unsigned long addr)
+static bool __kprobes within_kprobe_blacklist(unsigned long addr)
{
- struct kprobe_blackpoint *kb;
+ struct kprobe_blacklist_entry *ent;
if (arch_within_kprobe_blacklist(addr))
- return -EINVAL;
+ return true;
/*
* 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;
- }
+ list_for_each_entry(ent, &kprobe_blacklist, list) {
+ if (addr >= ent->start_addr && addr < ent->end_addr)
+ return true;
}
- return 0;
+
+ return false;
}
/*
@@ -1436,7 +1424,7 @@ static __kprobes int check_kprobe_address_safe(struct kprobe *p,
/* Ensure it is not in reserved area nor out of text */
if (!kernel_text_address((unsigned long) p->addr) ||
- in_kprobes_functions((unsigned long) p->addr) ||
+ within_kprobe_blacklist((unsigned long) p->addr) ||
jump_label_text_reserved(p->addr, p->addr)) {
ret = -EINVAL;
goto out;
@@ -2022,6 +2010,38 @@ void __kprobes dump_kprobe(struct kprobe *kp)
kp->symbol_name, kp->addr, kp->offset);
}
+/*
+ * 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.
+ */
+static int __init populate_kprobe_blacklist(unsigned long *start,
+ unsigned long *end)
+{
+ unsigned long *iter;
+ struct kprobe_blacklist_entry *ent;
+ unsigned long offset = 0, size = 0;
+
+ for (iter = start; iter < end; iter++) {
+ if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) {
+ pr_err("Failed to find blacklist %p\n", (void *)*iter);
+ continue;
+ }
+
+ ent = kmalloc(sizeof(*ent), GFP_KERNEL);
+ if (!ent)
+ return -ENOMEM;
+ ent->start_addr = *iter;
+ ent->end_addr = *iter + size;
+ INIT_LIST_HEAD(&ent->list);
+ list_add_tail(&ent->list, &kprobe_blacklist);
+ }
+ return 0;
+}
+
/* Module notifier call back, checking kprobes on the module */
static int __kprobes kprobes_module_callback(struct notifier_block *nb,
unsigned long val, void *data)
@@ -2065,14 +2085,13 @@ static struct notifier_block kprobe_module_nb = {
.priority = 0
};
+/* Markers of _kprobe_blacklist section */
+extern unsigned long __start_kprobe_blacklist[];
+extern unsigned long __stop_kprobe_blacklist[];
+
static int __init init_kprobes(void)
{
int i, err = 0;
- unsigned long offset = 0, size = 0;
- char *modname, namebuf[KSYM_NAME_LEN];
- const char *symbol_name;
- void *addr;
- struct kprobe_blackpoint *kb;
/* FIXME allocate the probe table, currently defined statically */
/* initialize all list heads */
@@ -2082,26 +2101,11 @@ static int __init init_kprobes(void)
raw_spin_lock_init(&(kretprobe_table_locks[i].lock));
}
- /*
- * 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;
+ err = populate_kprobe_blacklist(__start_kprobe_blacklist,
+ __stop_kprobe_blacklist);
+ if (err) {
+ pr_err("kprobes: failed to populate blacklist: %d\n", err);
+ pr_err("Please take care of using kprobes.\n");
}
if (kretprobe_blacklist_size) {