Messages in this thread | | | Date | Mon, 15 Apr 2013 12:30:11 +0800 | From | Chen Gang <> | Subject | Re: [PATCH v2] kernel: kallsyms: memory override issue, need check destination buffer length |
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On 2013年04月15日 10:05, Rusty Russell wrote: > Chen Gang <gang.chen@asianux.com> writes: >> > We don't export any symbols > 128 characters, but if we did then >> > kallsyms_expand_symbol() would overflow the buffer handed to it. >> > So we need check destination buffer length when copying. >> > >> > the related test: >> > if we define an EXPORT function which name more than 128. >> > will panic when call kallsyms_lookup_name by init_kprobes on booting. >> > after check the length (provide this patch), it is ok. >> > >> > Implementaion: >> > add additional destination buffer length parameter (maxlen) >> > if uncompressed string is too long (>= maxlen), it will be truncated. >> > not check the parameters whether valid, since it is a static function. > Found a bug already: > > kernel/kallsyms.c: In function ‘kallsyms_lookup’: > kernel/kallsyms.c:305:78: error: negative width in bit-field ‘<anonymous>’ > kernel/kallsyms.c: In function ‘lookup_symbol_name’: > kernel/kallsyms.c:327:78: error: negative width in bit-field ‘<anonymous>’ > kernel/kallsyms.c: In function ‘lookup_symbol_attrs’: > kernel/kallsyms.c:346:69: error: negative width in bit-field ‘<anonymous>’ >
oh... it is my fault, I will send v3.
I only tested kallsyms_on_each_symbol and kallsyms_lookup_name (they were of cause OK). , not test others.
ARRAY_SIZE is really valuable to help find bugs.
and next, after code changes, I should compile it again, at least.
:-)
> Cheers,
-- Chen Gang
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