@@ -41,18 +41,9 @@ const char *ll_addr_n2a(const unsigned char *addr, int alen, int type, char *buf
if (alen == 16 && type == ARPHRD_TUNNEL6) {
return inet_ntop(AF_INET6, addr, buf, blen);
}
- l = 0;
- for (i=0; i<alen; i++) {
- if (i==0) {
- snprintf(buf+l, blen, "%02x", addr[i]);
- blen -= 2;
- l += 2;
- } else {
- snprintf(buf+l, blen, ":%02x", addr[i]);
- blen -= 3;
- l += 3;
- }
- }
+ snprintf(buf, blen, "%02x", addr[0]);
+ for (i = 1, l = 2; i < alen && l < blen; i++, l += 3)
+ snprintf(buf + l, blen - l, ":%02x", addr[i]);
return buf;
}
Apart from making the code a bit more compact and efficient, this also prevents a potential buffer overflow if the passed buffer is really too small: Although correctly decrementing the size parameter passed to snprintf, it could become negative which would then wrap since snprintf uses (unsigned) size_t for the parameter. Signed-off-by: Phil Sutter <phil@nwl.cc> --- lib/ll_addr.c | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-)