Messages in this thread | | | Subject | Re: [PATCH v4 3/7] kprobes: validate the symbol name provided during probe registration | From | Paul Clarke <> | Date | Fri, 21 Apr 2017 08:11:40 -0500 |
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a nit or two, below...
On 04/21/2017 07:32 AM, Naveen N. Rao wrote: > diff --git a/kernel/kprobes.c b/kernel/kprobes.c > index 6a128f3a7ed1..ff9b1ac72a38 100644 > --- a/kernel/kprobes.c > +++ b/kernel/kprobes.c > @@ -1383,6 +1383,34 @@ bool within_kprobe_blacklist(unsigned long addr) > } > > /* > + * We mainly want to ensure that the provided string is of a reasonable length > + * and is of the form [<mod_name>:]<sym_name>, so that this is safe to process > + * further. > + * We don't worry about invalid characters as those will just prevent > + * matching existing kallsyms. > + */ > +bool is_valid_kprobe_symbol_name(const char *name) > +{ > + size_t sym_len; > + const char *s; > + > + s = strnchr(name, ':', MODULE_NAME_LEN + KSYM_NAME_LEN + 1); > + if (s) { > + sym_len = (size_t)(s - name); > + if (sym_len <= 0 || sym_len >= MODULE_NAME_LEN)
"sym_len <= 0" looks odd here, since sym_len is likely unsigned and would never be less than zero, anyway.
> + return false; > + s++; > + } else > + s = name; > + > + sym_len = strnlen(s, KSYM_NAME_LEN); > + if (sym_len <= 0 || sym_len >= KSYM_NAME_LEN)
here, too.
> + return false; > + > + return true; > +}
PC
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