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[PATCH][2.6.25-rc2-mm1] fix a null pointer bug in register_kretprobe
- From: Masami Hiramatsu <mhiramat at redhat dot com>
- To: LKML <linux-kernel at vger dot kernel dot org>, Andrew Morton <akpm at linux-foundation dot org>
- Cc: Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, systemtap-ml <systemtap at sources dot redhat dot com>, Jim Keniston <jkenisto at us dot ibm dot com>
- Date: Mon, 03 Mar 2008 17:26:36 -0500
- Subject: [PATCH][2.6.25-rc2-mm1] fix a null pointer bug in register_kretprobe
Fix a bug in regiseter_kretprobe() which does not check
rp->kp.symbol_name == NULL before calling kprobe_lookup_name.
For maintainability, this introduces kprobe_addr helper function which
resolves addr field. It is used by register_kprobe and register_kretprobe.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
CC: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
CC: Jim Keniston <jkenisto@us.ibm.com>
---
kernel/kprobes.c | 43 ++++++++++++++++++++++++++-----------------
1 file changed, 26 insertions(+), 17 deletions(-)
Index: 2.6.25-rc2-mm1/kernel/kprobes.c
===================================================================
--- 2.6.25-rc2-mm1.orig/kernel/kprobes.c 2008-02-18 11:37:18.000000000 -0500
+++ 2.6.25-rc2-mm1/kernel/kprobes.c 2008-02-18 11:37:18.000000000 -0500
@@ -498,27 +498,36 @@ static int __kprobes in_kprobes_function
return 0;
}
+/*
+ * If we have a symbol_name argument, look it up and add the offset field
+ * to it. This way, we can specify a relative address to a symbol.
+ */
+static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
+{
+ kprobe_opcode_t *addr = p->addr;
+ if (p->symbol_name) {
+ if (addr)
+ return NULL;
+ kprobe_lookup_name(p->symbol_name, addr);
+ }
+
+ if (!addr)
+ return NULL;
+ return (kprobe_opcode_t *)(((char *)addr) + p->offset);
+}
+
static int __kprobes __register_kprobe(struct kprobe *p,
unsigned long called_from)
{
int ret = 0;
struct kprobe *old_p;
struct module *probed_mod;
+ kprobe_opcode_t *addr;
- /*
- * If we have a symbol_name argument look it up,
- * and add it to the address. That way the addr
- * field can either be global or relative to a symbol.
- */
- if (p->symbol_name) {
- if (p->addr)
- return -EINVAL;
- kprobe_lookup_name(p->symbol_name, p->addr);
- }
-
- if (!p->addr)
+ addr = kprobe_addr(p);
+ if (!addr)
return -EINVAL;
- p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset);
+ p->addr = addr;
if (!kernel_text_address((unsigned long) p->addr) ||
in_kprobes_functions((unsigned long) p->addr))
@@ -722,12 +731,12 @@ int __kprobes register_kretprobe(struct
int ret = 0;
struct kretprobe_instance *inst;
int i;
- void *addr = rp->kp.addr;
+ void *addr;
if (kretprobe_blacklist_size) {
- if (addr == NULL)
- kprobe_lookup_name(rp->kp.symbol_name, addr);
- addr += rp->kp.offset;
+ addr = kprobe_addr(&rp->kp);
+ if (!addr)
+ return -EINVAL;
for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
if (kretprobe_blacklist[i].addr == addr)
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com