On Wed, Jan 6, 2016 at 3:28 AM, Fengguang Wu <[email protected]> wrote: > Hi Steven, > > On Mon, Jan 04, 2016 at 10:42:46AM -0500, Steven Rostedt wrote: >> On Wed, 30 Dec 2015 23:06:41 +0000 >> Colin King <[email protected]> wrote: >> >> > From: Colin Ian King <[email protected]> >> > >> > Fix build warning: >> > >> > scripts/recordmcount.c:589:4: warning: format not a string >> > literal and no format arguments [-Wformat-security] >> > sprintf("%s: failed\n", file); >> > >> > Fixes: a50bd43935586 ("ftrace/scripts: Have recordmcount copy the object >> > file") >> > Signed-off-by: Colin Ian King <[email protected]> >> > --- >> > scripts/recordmcount.c | 2 +- >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> > >> > diff --git a/scripts/recordmcount.c b/scripts/recordmcount.c >> > index 301d70b..e1675927 100644 >> > --- a/scripts/recordmcount.c >> > +++ b/scripts/recordmcount.c >> > @@ -586,7 +586,7 @@ main(int argc, char *argv[]) >> > do_file(file); >> > break; >> > case SJ_FAIL: /* error in do_file or below */ >> > - sprintf("%s: failed\n", file); >> > + fprintf(stderr, "%s: failed\n", file); >> >> Paper bag bug. I'm not sure how this passed my tests? My tests check >> for warnings. And I even got a "BUILD SUCCESS" from Fengguang Wu's >> kbuild test robot. > > Because the error will only show up on "gcc -Wformat-security".
I wish GCC were smarter about this. I would have hoped at least ONE of the various -Wformat... options would warn about "you did not actually specify a buffer for sprintf". But yeah, this comes from -Wformat-security (a subset of -Wformat-nonliteral), but can't be turned on by default, as mentioned by Fengguang. > It tend to raise false positives, so Kees setup a dedicated tree > which enables -Wformat-security as well as quieting the common false > positives. In that way Kees can catch such problems from time to time, > however the limitation is, only upstreamed code can be tested in Kees' > tree. -Kees -- Kees Cook Chrome OS & Brillo Security -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
