Messages in this thread |  | | From | Michael Ellerman <> | Subject | Re: [PATCH v4 3/7] kprobes: validate the symbol name provided during probe registration | Date | Sat, 22 Apr 2017 15:55:21 +1000 |
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"Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com> writes:
> When a kprobe is being registered, we use the symbol_name field to > lookup the address where the probe should be placed. Since this is a > user-provided field, let's ensure that the length of the string is > within expected limits.
What are we actually trying to protect against here?
If you ignore powerpc for a moment, kprobe_lookup_name() is just kallsyms_lookup_name().
All kallsyms_lookup_name() does with name is strcmp() it against a legitimate symbol name which is at most KSYM_NAME_LEN.
So I don't think any of this validation helps in that case?
In the powerpc version of kprobe_lookup_name() we do need to do some string juggling, for which it helps to know the input is sane. But I think we should just make that code more robust by checking the input before we do anything with it.
cheers
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