| Message ID | 20181026232409.16100-8-linux@rasmusvillemoes.dk (mailing list archive) |
|---|---|
| State | Rejected |
| Headers | show |
| Series | runtime format string checking | expand |
Hi, On Sat, Oct 27, 2018 at 01:24:09AM +0200, Rasmus Villemoes wrote: > With -Wformat-nonliteral, gcc complains > > drivers/hwmon/hwmon.c: In function ‘hwmon_genattr’: > drivers/hwmon/hwmon.c:282:6: warning: format not a string literal, argument types not checked [-Wformat-nonliteral] > index + hwmon_attr_base(type)); > > Add a runtime check to ensure that the template indeed has a single %d > printf specifier. Using fmtcheck() also makes gcc verify that the > expression 'index + hwmon_attr_base(type)' is suitable for %d. > > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> I'll defer to others on this one; let me know if the series is otherwise accepted. Personally I think that the compiler is at fault here for not detecting that the format string can not be wrong (since it is declared and used only in this file), and I find the fmtcheck() confusing/obfuscating. Guenter > --- > drivers/hwmon/hwmon.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c > index 33d51281272b..ec6f5f36b5fc 100644 > --- a/drivers/hwmon/hwmon.c > +++ b/drivers/hwmon/hwmon.c > @@ -278,7 +278,8 @@ static struct attribute *hwmon_genattr(struct device *dev, > if (type == hwmon_chip) { > name = (char *)template; > } else { > - scnprintf(hattr->name, sizeof(hattr->name), template, > + scnprintf(hattr->name, sizeof(hattr->name), > + fmtcheck(template, "type%dwhat", 0), > index + hwmon_attr_base(type)); > name = hattr->name; > }
diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c index 33d51281272b..ec6f5f36b5fc 100644 --- a/drivers/hwmon/hwmon.c +++ b/drivers/hwmon/hwmon.c @@ -278,7 +278,8 @@ static struct attribute *hwmon_genattr(struct device *dev, if (type == hwmon_chip) { name = (char *)template; } else { - scnprintf(hattr->name, sizeof(hattr->name), template, + scnprintf(hattr->name, sizeof(hattr->name), + fmtcheck(template, "type%dwhat", 0), index + hwmon_attr_base(type)); name = hattr->name; }
With -Wformat-nonliteral, gcc complains drivers/hwmon/hwmon.c: In function ‘hwmon_genattr’: drivers/hwmon/hwmon.c:282:6: warning: format not a string literal, argument types not checked [-Wformat-nonliteral] index + hwmon_attr_base(type)); Add a runtime check to ensure that the template indeed has a single %d printf specifier. Using fmtcheck() also makes gcc verify that the expression 'index + hwmon_attr_base(type)' is suitable for %d. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> --- drivers/hwmon/hwmon.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)