On Thu, Jul 23, 2015 at 1:50 PM, Andy Shevchenko <andriy.shevche...@linux.intel.com> wrote: > On Thu, 2015-07-23 at 13:36 -0700, Kees Cook wrote: >> On Thu, Jul 23, 2015 at 1:27 PM, Andy Shevchenko >> <andriy.shevche...@linux.intel.com> wrote: >> > On Thu, 2015-07-23 at 12:59 -0700, Kees Cook wrote: >> > > Hi, >> > > >> > > I'm curious why ESCAPE_SPACE doesn't escape spaces (0x20)? >> > >> > Space is a printable character. >> > You perhaps wants something like ESCAPE_SPACE | ESCAPE_HEX. >> >> Yeah, I can get the effect I want with: >> >> flags = ESCAPE_SPACE | ESCAPE_SPECIAL | ESCAPE_NULL | ESCAPE_HEX; >> esc = "\f\n\r\t\v\\\a\e\0 "; > > esc can't contain '\0' in the middle.
Ah, yes, of course. > So, you would like to convert only space to hex and leave everything > else printable as is? That was one idea I was having, yes. >> This isn't reachable via kasprintf, though (it always has a NULL >> esc). >> I will consider some options and send patches. > > Before doing this, describe your use case in detail, please. Sure. I'd like to be able to hex-escape everything <0x20, >0x7f, and ". (I'm working on building a quotable string that is safe to log.) I think I've settled for a subset of this as: string_escape_mem(src, slen, dst, 0, ESCAPE_HEX, "\f\n\r\t\v\a\e\\\"") >> > > That is >> > > surprising to me, especially since things like isspace() include >> > > 0x20. >> > >> > Moreover, there are test cases in test-string_helpers.c module and >> > they >> > are based on the real use cases (before helpers were introduced and >> > users were converted). So, there is no user which expects hex >> > conversio >> > n of the printable character if not asked explicitly. >> >> Yeah, I saw it was testing for space to be excluded. I guess I just >> think the name "ESCAPE_SPACE" is misleading. :) > > For sake of name shortness I suppose. The idea is to escape *special* > spaces by this. Makes sense. I'll send a patch with some clarifications on the comments. Thanks! -Kees -- Kees Cook Chrome OS Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
