Re: [LTP] [PATCH v10 3/3] coredump02: Verify ELF structure and notes

[Andrea Cervesato via ltp <ltp@lists.linux.it>]

Hi Cyril,

> Hi!
> > +static void handle_note(uint32_t type, const void *desc, size_t descsz, pid_t pid)
> > +{
> > +	if (type == NT_PRPSINFO && descsz >= sizeof(struct elf_prpsinfo)) {
> > +		struct elf_prpsinfo info;
> > +
> > +		memcpy(&info, desc, sizeof(info));
> > +		TST_EXP_EQ_STR(info.pr_fname, "coredump02");
> 
> I still do not see a reason why this can't be:
> 
> 		struct elf_prpsinfo *info = desc;
> 
> 		TST_EXP_EQ_STR(info->pr_name, "coredump02");

because ELF notes in Linux are only 4-byte padded, desc pointers are not
guaranteed to be 8-byte aligned. Casting desc to struct elf_prpsinfo *
or struct elf_prstatus * creates a misaligned pointer, which is undefined
behavior in C.

--
Andrea Cervesato
SUSE QE Automation Engineer Linux
andrea.cervesato@suse.com

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