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kprobes: fix a null pointer bug in register_kretprobe()

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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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Masami Hiramatsu 2008-03-04 14:29:44 -08:00 committed by Linus Torvalds
parent 1913130553
commit b2a5cd6938
1 changed files with 26 additions and 17 deletions
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43
kernel/kprobes.c
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@ -498,27 +498,36 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
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))
@ -721,12 +730,12 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
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)