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kprobes: Introduce NOKPROBE_SYMBOL() macro to maintain kprobes blacklist

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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>
This commit is contained in:
Masami Hiramatsu
2014-04-17 17:17:05 +09:00
committed by Ingo Molnar
parent be8f274323
commit 376e242429
8 changed files with 107 additions and 52 deletions
Download Patch File Download Diff File Expand all files Collapse all files

100
kernel/kprobes.c
View File

@@ -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) {