Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH v2] powerpc/64: Fix build failure with GCC 8.1 | Date | Thu, 31 May 2018 21:17:20 +1000 |
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Christophe LEROY <christophe.leroy@c-s.fr> writes: > Le 31/05/2018 à 07:54, Michael Ellerman a écrit : >> Christophe LEROY <christophe.leroy@c-s.fr> writes: >>> Le 29/05/2018 à 11:05, Geert Uytterhoeven a écrit : >>>> Hi Christophe, >>>> On Tue, May 29, 2018 at 10:56 AM, Christophe LEROY >>>> <christophe.leroy@c-s.fr> wrote: >>>>> Le 29/05/2018 à 09:47, Geert Uytterhoeven a écrit : >>>>>> On Tue, May 29, 2018 at 8:03 AM, Christophe Leroy >>>>>>> --- a/arch/powerpc/kernel/nvram_64.c >>>>>>> +++ b/arch/powerpc/kernel/nvram_64.c >>>>>>> @@ -1039,7 +1039,7 @@ loff_t __init nvram_create_partition(const char >>>>>>> *name, int sig, >>>>>>> new_part->index = free_part->index; >>>>>>> new_part->header.signature = sig; >>>>>>> new_part->header.length = size; >>>>>>> - strncpy(new_part->header.name, name, 12); >>>>>>> + memcpy(new_part->header.name, name, strnlen(name, >>>>>>> sizeof(new_part->header.name))); >>>>>> >>>>>> >>>>>> The comment for nvram_header.lgnth says: >>>>>> >>>>>> /* Terminating null required only for names < 12 chars. */ >>>>>> >>>>>> This will not terminate the string with a zero (the struct is >>>>>> allocated with kmalloc). >>>>>> So the original code is correct, the new one isn't. >>>>> >>>>> Right, then I have to first zeroize the destination. >>>> >>>> Using kzalloc() instead of kmalloc() will do. >>>> >>>> Still, papering around these warnings seems to obscure things, IMHO. >>>> And it increases code size, as you had to add a call to strnlen(). >> >> >> The right fix is to not try and mirror the on-device structure in the >> kernel struct. We should just use a proper NULL terminated string, which >> would avoid the need to explicitly do strncmp(.., .., 12) in the code >> and be less bug prone in general. >> >> The only place where we should need to worry about the 12 byte buffer is >> in nvram_write_header(). >> >> Anyway that's a bigger change, so I'll take this for now with kzalloc(). > > Thanks. You take it as is and add the kzalloc() or you expect a v3 from > me with the kzalloc()
Sorry that wasn't clear was it. I'll add the kzalloc().
cheers
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