kprobes: support kretprobe blacklist

Introduce architecture dependent kretprobe blacklists to prohibit users
from inserting return probes on the function in which kprobes can be
inserted but kretprobes can not.

This patch also removes "__kprobes" mark from "__switch_to" on x86_64 and
registers "__switch_to" to the blacklist on x86-64, because that mark is to
prohibit user from inserting only kretprobe.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Acked-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/avr32/kernel/kprobes.c b/arch/avr32/kernel/kprobes.c
index 4942ee662e0b53c14fb84c572a1902992433a031..20b1c9d8f945e1e68e994286728476f548d82bf2 100644 (file)
--- a/arch/avr32/kernel/kprobes.c
+++ b/arch/avr32/kernel/kprobes.c
@@ -22,6 +22,8 @@ DEFINE_PER_CPU(struct kprobe *, current_kprobe);
 static unsigned long kprobe_status;
 static struct pt_regs jprobe_saved_regs;
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
 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 5dc98b5abcfbcc3de963e60faaa139d86d362170..5fd65d8302c8561e50cf12a576f0c54569c30d1d 100644 (file)
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -40,6 +40,8 @@ extern void jprobe_inst_return(void);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
 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/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index 440f5a87271faf8e9467e198db21677e49ceded6..5338e48557127ca02e8238f421f73bcb88ae33b0 100644 (file)
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -38,6 +38,8 @@
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
 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 e40373d9fbce7ba975f3cbba412c70368988273d..c5549a20628450f31794d708c63f6fa80bab89ac 100644 (file)
--- a/arch/s390/kernel/kprobes.c
+++ b/arch/s390/kernel/kprobes.c
@@ -33,6 +33,8 @@
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
        /* Make sure the probe isn't going on a difficult instruction */

diff --git a/arch/sparc64/kernel/kprobes.c b/arch/sparc64/kernel/kprobes.c
index c93a15b785fa28322b5c254040ceb510904e7113..d94f901d321e91423e25f26fee5ccf3f57907c8f 100644 (file)
--- a/arch/sparc64/kernel/kprobes.c
+++ b/arch/sparc64/kernel/kprobes.c
@@ -42,6 +42,8 @@
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {{NULL, NULL}};
+
 int __kprobes arch_prepare_kprobe(struct kprobe *p)
 {
        p->ainsn.insn[0] = *p->addr;

diff --git a/arch/x86/kernel/kprobes_32.c b/arch/x86/kernel/kprobes_32.c
index 06b86e5617f62c739bdc4b448985d46462078273..90f778c04b3f1b847ea6c8653ae2f0c9503a8e39 100644 (file)
--- a/arch/x86/kernel/kprobes_32.c
+++ b/arch/x86/kernel/kprobes_32.c
@@ -41,6 +41,13 @@ void jprobe_return_end(void);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {
+       {"__switch_to", }, /* This function switches only current task, but
+                            doesn't switch kernel stack.*/
+       {NULL, NULL}    /* Terminator */
+};
+const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
+
 /* insert a jmp code */
 static __always_inline void set_jmp_op(void *from, void *to)
 {

diff --git a/arch/x86/kernel/kprobes_64.c b/arch/x86/kernel/kprobes_64.c
index 7c16506d681fc56f985c65f2c4b22dea7a5019ea..681b801c5e26bf7be2a09c24134f590381214258 100644 (file)
--- a/arch/x86/kernel/kprobes_64.c
+++ b/arch/x86/kernel/kprobes_64.c
@@ -48,6 +48,13 @@ static void __kprobes arch_copy_kprobe(struct kprobe *p);
 DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
 DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
 
+struct kretprobe_blackpoint kretprobe_blacklist[] = {
+       {"__switch_to", }, /* This function switches only current task, but
+                             doesn't switch kernel stack.*/
+       {NULL, NULL}    /* Terminator */
+};
+const int kretprobe_blacklist_size = ARRAY_SIZE(kretprobe_blacklist);
+
 /*
  * returns non-zero if opcode modifies the interrupt flag.
  */

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 7352d4b377e6d0f411bf1a6cf9d26e9266afacaa..6309b275cb9c176f61133fa7fc2b5585c9063fd4 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -581,7 +581,7 @@ static inline void __switch_to_xtra(struct task_struct *prev_p,
  *
  * Kprobes not supported here. Set the probe on schedule instead.
  */
-__kprobes struct task_struct *
+struct task_struct *
 __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 {
        struct thread_struct *prev = &prev_p->thread,

diff --git a/include/asm-avr32/kprobes.h b/include/asm-avr32/kprobes.h
index 0f3e636e6e4dda8d36c89b50f697777f59bdf88d..996cb656474e267920ad6856f6445156349b0579 100644 (file)
--- a/include/asm-avr32/kprobes.h
+++ b/include/asm-avr32/kprobes.h
@@ -17,6 +17,8 @@ typedef u16   kprobe_opcode_t;
 #define BREAKPOINT_INSTRUCTION 0xd673  /* breakpoint */
 #define MAX_INSN_SIZE          2
 
+#define kretprobe_blacklist_size 0
+
 #define arch_remove_kprobe(p)  do { } while (0)
 
 /* Architecture specific copy of original instruction */

diff --git a/include/asm-ia64/kprobes.h b/include/asm-ia64/kprobes.h
index 6c79edf24d73adc1572b885417394bcb6c02ae13..a93ce9ef07ff7a5497a4806d99df460030b080aa 100644 (file)
--- a/include/asm-ia64/kprobes.h
+++ b/include/asm-ia64/kprobes.h
@@ -83,6 +83,7 @@ struct kprobe_ctlblk {
 };
 
 #define ARCH_SUPPORTS_KRETPROBES
+#define kretprobe_blacklist_size 0
 
 #define SLOT0_OPCODE_SHIFT     (37)
 #define SLOT1_p1_OPCODE_SHIFT  (37 - (64-46))

diff --git a/include/asm-powerpc/kprobes.h b/include/asm-powerpc/kprobes.h
index c16973d5de6287dc4c14d1572065d747c719416e..afabad230dbb4f212d057449f03f3fec3b79d171 100644 (file)
--- a/include/asm-powerpc/kprobes.h
+++ b/include/asm-powerpc/kprobes.h
@@ -82,6 +82,7 @@ typedef unsigned int kprobe_opcode_t;
 
 #define ARCH_SUPPORTS_KRETPROBES
 #define flush_insn_slot(p)     do { } while (0)
+#define kretprobe_blacklist_size 0
 
 void kretprobe_trampoline(void);
 extern void arch_remove_kprobe(struct kprobe *p);

diff --git a/include/asm-s390/kprobes.h b/include/asm-s390/kprobes.h
index 8bc67cc9ffd2972a64f9da56564892e54d48d7c5..948db3d0d05c194d4715706fe4c932a781d23e4e 100644 (file)
--- a/include/asm-s390/kprobes.h
+++ b/include/asm-s390/kprobes.h
@@ -47,6 +47,7 @@ typedef u16 kprobe_opcode_t;
        : (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR)))
 
 #define ARCH_SUPPORTS_KRETPROBES
+#define kretprobe_blacklist_size 0
 
 #define KPROBE_SWAP_INST       0x10
 

diff --git a/include/asm-sparc64/kprobes.h b/include/asm-sparc64/kprobes.h
index a04145b77f9635e8a7a30504bef7f1b2cfdcc1e1..5020eaf67c292d10c34831cb71ce5ec421a6e8fd 100644 (file)
--- a/include/asm-sparc64/kprobes.h
+++ b/include/asm-sparc64/kprobes.h
@@ -10,6 +10,8 @@ typedef u32 kprobe_opcode_t;
 #define BREAKPOINT_INSTRUCTION_2 0x91d02071 /* ta 0x71 */
 #define MAX_INSN_SIZE 2
 
+#define kretprobe_blacklist_size 0
+
 #define arch_remove_kprobe(p)  do {} while (0)
 
 #define flush_insn_slot(p)             \

diff --git a/include/asm-x86/kprobes_32.h b/include/asm-x86/kprobes_32.h
index f2489d07ce88cdef0dec6d5d5d605a0d84a3c4f0..b772d5b386855cd4f3de9c52ab13f747f9257e25 100644 (file)
--- a/include/asm-x86/kprobes_32.h
+++ b/include/asm-x86/kprobes_32.h
@@ -45,6 +45,8 @@ typedef u8 kprobe_opcode_t;
 #define ARCH_SUPPORTS_KRETPROBES
 #define flush_insn_slot(p)     do { } while (0)
 
+extern const int kretprobe_blacklist_size;
+
 void arch_remove_kprobe(struct kprobe *p);
 void kretprobe_trampoline(void);
 

diff --git a/include/asm-x86/kprobes_64.h b/include/asm-x86/kprobes_64.h
index 3f495e5308b13499f4d7122e2bb90510bc293417..53f4d85073545641421291911acc3a319488868c 100644 (file)
--- a/include/asm-x86/kprobes_64.h
+++ b/include/asm-x86/kprobes_64.h
@@ -42,6 +42,7 @@ typedef u8 kprobe_opcode_t;
        : (((unsigned long)current_thread_info()) + THREAD_SIZE - (ADDR)))
 
 #define ARCH_SUPPORTS_KRETPROBES
+extern const int kretprobe_blacklist_size;
 
 void kretprobe_trampoline(void);
 extern void arch_remove_kprobe(struct kprobe *p);

diff --git a/include/linux/kprobes.h b/include/linux/kprobes.h
index 51464d12a4e5aa14b09a7a0d0b228055ba81b23a..81891581e89ba544a527aa994386374b4c1c2146 100644 (file)
--- a/include/linux/kprobes.h
+++ b/include/linux/kprobes.h
@@ -166,6 +166,12 @@ struct kretprobe_instance {
        struct task_struct *task;
 };
 
+struct kretprobe_blackpoint {
+       const char *name;
+       void *addr;
+};
+extern struct kretprobe_blackpoint kretprobe_blacklist[];
+
 static inline void kretprobe_assert(struct kretprobe_instance *ri,
        unsigned long orig_ret_address, unsigned long trampoline_address)
 {

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f9798ff7899f4a610823fd641fe5e2dde0e746f7..e3a5d817ac9b0f07b514587a7ec03453461ab655 100644 (file)
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -716,6 +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;
@@ -794,6 +806,17 @@ static int __init init_kprobes(void)
                INIT_HLIST_HEAD(&kretprobe_inst_table[i]);
        }
 
+       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;