Re: [Libguestfs] [PATCH v2 1/2] lib: change how hbin sections are read.

On Wed, 2017-02-15 at 16:50 -0500, Dawid Zamirski wrote: > On Wed, 2017-02-15 at 21:14 +0000, Richard W.M. Jones wrote: > > On Wed, Feb 15, 2017 at 02:28:41PM -0500, Dawid Zamirski wrote: > > > Correct, however there's also no guarantee that seeking by 4k in > > > "garbage" data would not land you in registry data that happens > > > to > > > evaluate to "hbin" as well. That's why I put "hbin" offset > > > validation > > > check couple of lines below to make sure that the "hbin" we found > > > by > > > searching is a proper one. The offset check I'm referring to is: > > > > > > /* get "stated" hbin offset from header */ > > > size_t page_offset = le32to(page->offset_first) + 0x1000; > > > > > > /* if that does not match our current file offset, > > >    then exit with error */ > > > if (page_offset != off) {  > > >   SET_ERRNO... > > > } > > > > Still, what kind of corruption would move a genuine hbin to a > > non-page-sized offset in the file?  It seems unlikely to me ... > > > > Rich. > > > > None that I know of :-) However I don't see any other simple way to > silence that GCC7 warning and it seems harmless that way to me > (besides > the fact that the loop will have to make more iterations) So I've found a way to keep offsetting by 4k and keep GCC7 happy: while (off < h->endpages) { if (off + 0x1000 > off) off += 0x1000; else break; // off would overflow Is this acceptable?