kprobes: 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -498,27 +498,36 @@ static int __kprobes in_kprobes_functions(unsigned long addr)
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return 0;
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}
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/*
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* If we have a symbol_name argument, look it up and add the offset field
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* to it. This way, we can specify a relative address to a symbol.
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*/
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static kprobe_opcode_t __kprobes *kprobe_addr(struct kprobe *p)
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{
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kprobe_opcode_t *addr = p->addr;
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if (p->symbol_name) {
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if (addr)
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return NULL;
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kprobe_lookup_name(p->symbol_name, addr);
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}
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if (!addr)
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return NULL;
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return (kprobe_opcode_t *)(((char *)addr) + p->offset);
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}
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static int __kprobes __register_kprobe(struct kprobe *p,
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unsigned long called_from)
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{
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int ret = 0;
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struct kprobe *old_p;
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struct module *probed_mod;
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kprobe_opcode_t *addr;
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/*
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* If we have a symbol_name argument look it up,
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* and add it to the address. That way the addr
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* field can either be global or relative to a symbol.
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*/
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if (p->symbol_name) {
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if (p->addr)
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return -EINVAL;
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kprobe_lookup_name(p->symbol_name, p->addr);
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}
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if (!p->addr)
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addr = kprobe_addr(p);
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if (!addr)
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return -EINVAL;
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p->addr = (kprobe_opcode_t *)(((char *)p->addr)+ p->offset);
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p->addr = addr;
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if (!kernel_text_address((unsigned long) p->addr) ||
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in_kprobes_functions((unsigned long) p->addr))
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@ -721,12 +730,12 @@ int __kprobes register_kretprobe(struct kretprobe *rp)
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int ret = 0;
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struct kretprobe_instance *inst;
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int i;
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void *addr = rp->kp.addr;
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void *addr;
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if (kretprobe_blacklist_size) {
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if (addr == NULL)
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kprobe_lookup_name(rp->kp.symbol_name, addr);
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addr += rp->kp.offset;
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addr = kprobe_addr(&rp->kp);
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if (!addr)
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return -EINVAL;
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for (i = 0; kretprobe_blacklist[i].name != NULL; i++) {
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if (kretprobe_blacklist[i].addr == addr)
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