py/mpprint: Fail an assertion with unsupported format specifiers.

Arguments of an unknown type cannot be skipped and continuing to parse a
format string after encountering an unknown format specifier leads to
undefined behaviour.  This patch helps to find use of unsupported formats.
This commit is contained in:
Delio Brignoli 2016-08-20 10:51:28 +02:00 committed by Damien George
parent ce1c786297
commit f98bb2ddcb
3 changed files with 3 additions and 4 deletions

View File

@ -537,10 +537,12 @@ int mp_vprintf(const mp_print_t *print, const char *fmt, va_list args) {
chrs += mp_print_int(print, arg_value, *fmt == 'd', 10, 'a', flags, fill, width);
break;
}
// fall through to default case to print unknown format char
assert(!"unsupported fmt char");
}
#endif
default:
// if it's not %% then it's an unsupported format character
assert(*fmt == '%' || !"unsupported fmt char");
print->print_strn(print->data, fmt, 1);
chrs += 1;
break;

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@ -7,7 +7,6 @@ ab abc
false true
(null)
t
-2147483648
2147483648
80000000

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@ -12,7 +12,6 @@ STATIC mp_obj_t extra_coverage(void) {
// mp_printf (used by ports that don't have a native printf)
{
mp_printf(&mp_plat_print, "# mp_printf\n");
mp_printf(&mp_plat_print, "%"); // nothing after percent
mp_printf(&mp_plat_print, "%d %+d % d\n", -123, 123, 123); // sign
mp_printf(&mp_plat_print, "%05d\n", -123); // negative number with zero padding
mp_printf(&mp_plat_print, "%ld\n", 123); // long
@ -21,7 +20,6 @@ STATIC mp_obj_t extra_coverage(void) {
mp_printf(&mp_plat_print, "%.*s\n", -1, "abc"); // negative string precision
mp_printf(&mp_plat_print, "%b %b\n", 0, 1); // bools
mp_printf(&mp_plat_print, "%s\n", NULL); // null string
mp_printf(&mp_plat_print, "%t\n"); // non-format char
mp_printf(&mp_plat_print, "%d\n", 0x80000000); // should print signed
mp_printf(&mp_plat_print, "%u\n", 0x80000000); // should print unsigned
mp_printf(&mp_plat_print, "%x\n", 0x80000000); // should print unsigned