diff options
| -rw-r--r-- | libc/inet/ether_addr.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/libc/inet/ether_addr.c b/libc/inet/ether_addr.c index 621c62989..9071d71de 100644 --- a/libc/inet/ether_addr.c +++ b/libc/inet/ether_addr.c @@ -38,10 +38,12 @@ struct ether_addr *ether_aton_r(const char *asc, struct ether_addr *addr) for (cnt = 0; cnt < 6; ++cnt) { unsigned char number; - char ch; + char ch = *asc++; + if (ch < 0x20) + return NULL; /* | 0x20 is cheap tolower(), valid for letters/numbers only */ - ch = (*asc++) | 0x20; + ch |= 0x20; if ((ch < '0' || ch > '9') && (ch < 'a' || ch > 'f')) return NULL; number = !(ch > '9') ? (ch - '0') : (ch - 'a' + 10); |