[PATCH v2 2/4] kprobes: split blacklist into common and arch

From: Oskar Andero
Date: Thu Apr 04 2013 - 08:53:11 EST

Some blackpoints are only valid for specific architectures. To let each
architecture specify its own blackpoints the list has been split in two
lists: common and arch. The common list is kept in kernel/kprobes.c and
the arch list is kept in the arch/ directory.

Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: linux-arch@xxxxxxxxxxxxxxx
Signed-off-by: Oskar Andero <oskar.andero@xxxxxxxxxxxxxx>
---
arch/arc/kernel/kprobes.c | 3 ++
arch/arm/kernel/kprobes.c | 2 +
arch/avr32/kernel/kprobes.c | 3 ++
arch/ia64/kernel/kprobes.c | 3 ++
arch/mips/kernel/kprobes.c | 3 ++
arch/mn10300/kernel/kprobes.c | 2 +
arch/powerpc/kernel/kprobes.c | 3 ++
arch/s390/kernel/kprobes.c | 3 ++
arch/sh/kernel/kprobes.c | 3 ++
arch/sparc/kernel/kprobes.c | 3 ++
arch/x86/kernel/kprobes/core.c | 3 ++
kernel/kprobes.c | 85 +++++++++++++++++++++++++++---------------
12 files changed, 86 insertions(+), 30 deletions(-)

diff --git a/arch/arc/kernel/kprobes.c b/arch/arc/kernel/kprobes.c
index 3bfeacb..894eee6 100644
--- a/arch/arc/kernel/kprobes.c
+++ b/arch/arc/kernel/kprobes.c
@@ -24,6 +24,9 @@
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
/* Attempt to probe at unaligned address */
diff --git a/arch/arm/kernel/kprobes.c b/arch/arm/kernel/kprobes.c
index 170e9f3..772d9ec 100644
--- a/arch/arm/kernel/kprobes.c
+++ b/arch/arm/kernel/kprobes.c
@@ -46,6 +46,8 @@
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);

int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
diff --git a/arch/avr32/kernel/kprobes.c b/arch/avr32/kernel/kprobes.c
index f820e9f..3b02c1e 100644
--- a/arch/avr32/kernel/kprobes.c
+++ b/arch/avr32/kernel/kprobes.c
@@ -24,6 +24,9 @@ static struct pt_regs jprobe_saved_regs;

struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
int ret = 0;
diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index f8280a7..239f2fd 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -42,6 +42,9 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
enum instruction_type {A, I, M, F, B, L, X, u};
static enum instruction_type bundle_encoding[32][3] = {
{ M, I, I }, /* 00 */
diff --git a/arch/mips/kernel/kprobes.c b/arch/mips/kernel/kprobes.c
index 12bc4eb..de6a1aa 100644
--- a/arch/mips/kernel/kprobes.c
+++ b/arch/mips/kernel/kprobes.c
@@ -53,6 +53,9 @@ static const union mips_instruction breakpoint2_insn = {
DEFINE_PER_CPU(struct kprobe *, current_kprobe);
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
static int __kprobes insn_has_delayslot(union mips_instruction insn)
{
switch (insn.i_format.opcode) {
diff --git a/arch/mn10300/kernel/kprobes.c b/arch/mn10300/kernel/kprobes.c
index 0311a7f..ed57094 100644
--- a/arch/mn10300/kernel/kprobes.c
+++ b/arch/mn10300/kernel/kprobes.c
@@ -41,6 +41,8 @@ static unsigned long cur_kprobe_bp_addr;

DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);

/* singlestep flag bits */
#define SINGLESTEP_BRANCH 1
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 11f5b03..b18ba45 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -47,6 +47,9 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
int ret = 0;
diff --git a/arch/s390/kernel/kprobes.c b/arch/s390/kernel/kprobes.c
index 3388b2b..2077bb0 100644
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -37,6 +37,9 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

struct kretprobe_blackpoint kretprobe_blacklist[] = { };

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
static int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn)
{
switch (insn[0] >> 8) {
diff --git a/arch/sh/kernel/kprobes.c b/arch/sh/kernel/kprobes.c
index 42b46e6..8acfb02 100644
--- a/arch/sh/kernel/kprobes.c
+++ b/arch/sh/kernel/kprobes.c
@@ -24,6 +24,9 @@ static DEFINE_PER_CPU(struct kprobe, saved_current_opcode);
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode);
static DEFINE_PER_CPU(struct kprobe, saved_next_opcode2);

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
#define OPCODE_JMP(x) (((x) & 0xF0FF) == 0x402b)
#define OPCODE_JSR(x) (((x) & 0xF0FF) == 0x400b)
#define OPCODE_BRA(x) (((x) & 0xF000) == 0xa000)
diff --git a/arch/sparc/kernel/kprobes.c b/arch/sparc/kernel/kprobes.c
index e722121..627e35c 100644
--- a/arch/sparc/kernel/kprobes.c
+++ b/arch/sparc/kernel/kprobes.c
@@ -45,6 +45,9 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
int __kprobes arch_prepare_kprobe(struct kprobe *p)
{
if ((unsigned long) p->addr & 0x3UL)
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 7bfe318..4aa71a5 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -65,6 +65,9 @@ void jprobe_return_end(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);

+const char * const arch_kprobes_blacksyms[] = {};
+const size_t arch_kprobes_blacksyms_size = ARRAY_SIZE(arch_kprobes_blacksyms);
+
#define stack_addr(regs) ((unsigned long *)kernel_stack_pointer(regs))

#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index 0a270e5..7654278 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -68,7 +68,6 @@
#endif

static int kprobes_initialized;
-static int kprobe_blacklist_initialized;
static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE];
static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE];

@@ -94,31 +93,60 @@ static raw_spinlock_t *kretprobe_table_lock_ptr(unsigned long hash)
*
* For such cases, we now have a blacklist
*/
-static struct kprobe_blackpoint kprobe_blacklist[] = {
- {"preempt_schedule",},
- {"native_get_debugreg",},
- {"irq_entries_start",},
- {"common_interrupt",},
- {"mcount",}, /* mcount can be called from everywhere */
- {NULL} /* Terminator */
+static const char * const common_kprobes_blacksyms[] = {
+ "preempt_schedule",
+ "native_get_debugreg",
+ "irq_entries_start",
+ "common_interrupt",
+ "mcount", /* mcount can be called from everywhere */
};
+static const size_t common_kprobes_blacksyms_size =
+ ARRAY_SIZE(common_kprobes_blacksyms);
+
+extern const char * const arch_kprobes_blacksyms[];
+extern const size_t arch_kprobes_blacksyms_size;
+
+static struct kprobe_blackpoint *kprobe_blacklist;
+static size_t kprobe_blacklist_size;
+
+static void init_kprobe_blacklist_entry(struct kprobe_blackpoint *kb,
+ const char * const name)
+{
+ const char *symbol_name;
+ char *modname, namebuf[128];
+ void *addr;
+ unsigned long offset = 0, size = 0;
+
+ kb->name = name;
+ kprobe_lookup_name(kb->name, addr);
+ if (!addr)
+ return;
+
+ 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;
+}

/* it can take some time ( > 100ms ) to initialise the
* blacklist so we delay this until we actually need it
*/
static void init_kprobe_blacklist(void)
{
- int i;
- unsigned long offset = 0, size = 0;
- char *modname, namebuf[128];
- const char *symbol_name;
- void *addr;
- struct kprobe_blackpoint *kb;
+ int i, j = 0;

mutex_lock(&kprobe_mutex);
- if (kprobe_blacklist_initialized)
+ if (kprobe_blacklist)
goto out;

+ kprobe_blacklist_size = common_kprobes_blacksyms_size +
+ arch_kprobes_blacksyms_size;
+ kprobe_blacklist = kzalloc(sizeof(*kprobe_blacklist) *
+ kprobe_blacklist_size, GFP_KERNEL);
+
/*
* Lookup and populate the kprobe_blacklist.
*
@@ -127,18 +155,14 @@ static void init_kprobe_blacklist(void)
* 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;
+ for (i = 0; i < common_kprobes_blacksyms_size; i++, j++) {
+ init_kprobe_blacklist_entry(&kprobe_blacklist[j],
+ common_kprobes_blacksyms[i]);
+ }

- 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;
+ for (i = 0; i < arch_kprobes_blacksyms_size; i++, j++) {
+ init_kprobe_blacklist_entry(&kprobe_blacklist[j],
+ arch_kprobes_blacksyms[i]);
}

if (kretprobe_blacklist_size) {
@@ -151,7 +175,6 @@ static void init_kprobe_blacklist(void)
kretprobe_blacklist[i].name);
}
}
- kprobe_blacklist_initialized = 1;

out:
mutex_unlock(&kprobe_mutex);
@@ -1382,18 +1405,20 @@ out:
static int __kprobes in_kprobes_functions(unsigned long addr)
{
struct kprobe_blackpoint *kb;
+ int i;

if (addr >= (unsigned long)__kprobes_text_start &&
addr < (unsigned long)__kprobes_text_end)
return -EINVAL;

- if (unlikely(!kprobe_blacklist_initialized))
+ if (unlikely(!kprobe_blacklist))
init_kprobe_blacklist();
/*
* If there exists a kprobe_blacklist, verify and
* fail any probe registration in the prohibited area
*/
- for (kb = kprobe_blacklist; kb->name != NULL; kb++) {
+ for (i = 0; i < kprobe_blacklist_size; i++) {
+ kb = &kprobe_blacklist[i];
if (kb->start_addr) {
if (addr >= kb->start_addr &&
addr < (kb->start_addr + kb->range))
@@ -1874,7 +1899,7 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
void *addr;

if (kretprobe_blacklist_size) {
- if (unlikely(!kprobe_blacklist_initialized))
+ if (unlikely(!kprobe_blacklist))
init_kprobe_blacklist();
addr = kprobe_addr(&rp->kp);
if (IS_ERR(addr))
--
1.8.1.5

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