Re: [PATCH 2/2] proc: use set_puts() at /proc/*/wchan
On Wed, 21 Feb 2018 09:57:49 +0100 Rasmus Villemoes wrote: > On 2018-02-21 01:02, Andrew Morton wrote: > > On Sat, 17 Feb 2018 16:06:42 +0200 Andy Shevchenko > > wrote: > > > >> On Sat, Feb 17, 2018 at 9:20 AM, Alexey Dobriyan > >> wrote: > >>> Signed-off-by: Alexey Dobriyan > >> > >> > >>> - seq_printf(m, "%s", symname); > >>> + seq_puts(m, symname); > >> > >> While this might have no security concerns, the pattern might be > >> brainlessly used by some janitors and there would have security > >> implications. > > > > And I'd like to see a changelog, please. One which explains why > > `symname' cannot have a %s (etc) in it, and never will. > > OK, since #youtoo: It doesn't _matter_ if symname is "%pHAHAHA %fooled > you ", seq_puts does not interpret it at > all. There are _never_ security implications with the above replacement. > Sure, seq_printf(m, symname) would be bad, but that's not what is being > done. doh, OK, sorry. RTFP, Andrew.
Re: [PATCH 2/2] proc: use set_puts() at /proc/*/wchan
On 2018-02-21 01:02, Andrew Morton wrote: > On Sat, 17 Feb 2018 16:06:42 +0200 Andy Shevchenko > wrote: > >> On Sat, Feb 17, 2018 at 9:20 AM, Alexey Dobriyan wrote: >>> Signed-off-by: Alexey Dobriyan >> >> >>> - seq_printf(m, "%s", symname); >>> + seq_puts(m, symname); >> >> While this might have no security concerns, the pattern might be >> brainlessly used by some janitors and there would have security >> implications. > > And I'd like to see a changelog, please. One which explains why > `symname' cannot have a %s (etc) in it, and never will. OK, since #youtoo: It doesn't _matter_ if symname is "%pHAHAHA %fooled you ", seq_puts does not interpret it at all. There are _never_ security implications with the above replacement. Sure, seq_printf(m, symname) would be bad, but that's not what is being done. AFAICT, this should always lead to slightly smaller code (one less parameter passed) and in all likelyhood also slightly faster (no format interpretation, no slow char-by-char handling by the string() function etc.). So the only case where I'd think this should not necessarily be done would be in a long sequence of seq_printf, where only one or two could be replaced by seq_puts/seq_putc. Rasmus
Re: [PATCH 2/2] proc: use set_puts() at /proc/*/wchan
On Sat, 17 Feb 2018 16:06:42 +0200 Andy Shevchenko wrote: > On Sat, Feb 17, 2018 at 9:20 AM, Alexey Dobriyan wrote: > > Signed-off-by: Alexey Dobriyan > > > > - seq_printf(m, "%s", symname); > > + seq_puts(m, symname); > > While this might have no security concerns, the pattern might be > brainlessly used by some janitors and there would have security > implications. And I'd like to see a changelog, please. One which explains why `symname' cannot have a %s (etc) in it, and never will.
Re: [PATCH 2/2] proc: use set_puts() at /proc/*/wchan
On Sat, Feb 17, 2018 at 04:06:42PM +0200, Andy Shevchenko wrote: > On Sat, Feb 17, 2018 at 9:20 AM, Alexey Dobriyan wrote: > > - seq_printf(m, "%s", symname); > > + seq_puts(m, symname); > > While this might have no security concerns, the pattern might be > brainlessly used by some janitors and there would have security > implications. Unless there is some kind of preprocessor which seamlessly converts one to another I'd continue converting.
Re: [PATCH 2/2] proc: use set_puts() at /proc/*/wchan
On Sat, Feb 17, 2018 at 9:20 AM, Alexey Dobriyan wrote: > Signed-off-by: Alexey Dobriyan > - seq_printf(m, "%s", symname); > + seq_puts(m, symname); While this might have no security concerns, the pattern might be brainlessly used by some janitors and there would have security implications. -- With Best Regards, Andy Shevchenko
[PATCH 2/2] proc: use set_puts() at /proc/*/wchan
Signed-off-by: Alexey Dobriyan
---
fs/proc/base.c |2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -396,7 +396,7 @@ static int proc_pid_wchan(struct seq_file *m, struct
pid_namespace *ns,
wchan = get_wchan(task);
if (wchan && !lookup_symbol_name(wchan, symname)) {
- seq_printf(m, "%s", symname);
+ seq_puts(m, symname);
return 0;
}
