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dnsd: fixes various segfaults.

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One was a lib api change that was not updated and another
is a stack buffer overflow.
It also adds support for '*' in dnsd.conf. It resolves all hostnames to
a specific ip address. This is useful if you for example want redirect
all http traffic to your first-boot-web-wizard on you router/firewall.

By Timo Teras
This commit is contained in:
Denis Vlasenko 2008-05-22 17:41:01 +00:00
parent ae84b11467
commit e9b76e1f1e
2 changed files with 16 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
libbb/udp_io.c
View File

@ -36,11 +36,12 @@ send_to_from(int fd, void *buf, size_t len, int flags,
#else #else
struct iovec iov[1]; struct iovec iov[1];
struct msghdr msg; struct msghdr msg;
char cbuf[sizeof(struct in_pktinfo) union {
char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO) #if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
| sizeof(struct in6_pktinfo) /* (a|b) is poor man's max(a,b) */ char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
#endif #endif
]; } u;
struct cmsghdr* cmsgptr; struct cmsghdr* cmsgptr;
if (from->sa_family != AF_INET if (from->sa_family != AF_INET
@ -57,15 +58,15 @@ send_to_from(int fd, void *buf, size_t len, int flags,
iov[0].iov_base = buf; iov[0].iov_base = buf;
iov[0].iov_len = len; iov[0].iov_len = len;
memset(cbuf, 0, sizeof(cbuf)); memset(&u, 0, sizeof(u));
memset(&msg, 0, sizeof(msg)); memset(&msg, 0, sizeof(msg));
msg.msg_name = (void *)(struct sockaddr *)to; /* or compiler will annoy us */ msg.msg_name = (void *)(struct sockaddr *)to; /* or compiler will annoy us */
msg.msg_namelen = tolen; msg.msg_namelen = tolen;
msg.msg_iov = iov; msg.msg_iov = iov;
msg.msg_iovlen = 1; msg.msg_iovlen = 1;
msg.msg_control = cbuf; msg.msg_control = &u;
msg.msg_controllen = sizeof(cbuf); msg.msg_controllen = sizeof(u);
msg.msg_flags = flags; msg.msg_flags = flags;
cmsgptr = CMSG_FIRSTHDR(&msg); cmsgptr = CMSG_FIRSTHDR(&msg);
@ -89,6 +90,8 @@ send_to_from(int fd, void *buf, size_t len, int flags,
pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr; pktptr->ipi6_addr = ((struct sockaddr_in6*)from)->sin6_addr;
} }
#endif #endif
msg.msg_controllen = cmsgptr->cmsg_len;
return sendmsg(fd, &msg, flags); return sendmsg(fd, &msg, flags);
#endif #endif
} }
@ -109,7 +112,9 @@ recv_from_to(int fd, void *buf, size_t len, int flags,
struct iovec iov[1]; struct iovec iov[1];
union { union {
char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))]; char cmsg[CMSG_SPACE(sizeof(struct in_pktinfo))];
#if ENABLE_FEATURE_IPV6 && defined(IPV6_PKTINFO)
char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))]; char cmsg6[CMSG_SPACE(sizeof(struct in6_pktinfo))];
#endif
} u; } u;
struct cmsghdr *cmsgptr; struct cmsghdr *cmsgptr;
struct msghdr msg; struct msghdr msg;

8
networking/dnsd.c
View File

@ -194,7 +194,8 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
for (i = 1; i <= (int)(d->name[0]); i++) for (i = 1; i <= (int)(d->name[0]); i++)
if (tolower(qs[i]) != d->name[i]) if (tolower(qs[i]) != d->name[i])
break; break;
if (i > (int)(d->name[0])) { if (i > (int)(d->name[0]) ||
(d->name[0] == 1 && d->name[1] == '*')) {
strcpy((char *)as, d->ip); strcpy((char *)as, d->ip);
#if DEBUG #if DEBUG
fprintf(stderr, " OK as:%s\n", as); fprintf(stderr, " OK as:%s\n", as);
@ -202,7 +203,8 @@ static int table_lookup(uint16_t type, uint8_t * as, uint8_t * qs)
return 0; return 0;
} }
} else if (type == REQ_PTR) { /* search by IP-address */ } else if (type == REQ_PTR) { /* search by IP-address */
if (!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) { if ((d->name[0] != 1 || d->name[1] != '*') &&
!strncmp((char*)&d->rip[1], (char*)&qs[1], strlen(d->rip)-1)) {
strcpy((char *)as, d->name); strcpy((char *)as, d->name);
return 0; return 0;
} }
@ -401,7 +403,7 @@ int dnsd_main(int argc ATTRIBUTE_UNUSED, char **argv)
r = process_packet(buf); r = process_packet(buf);
if (r <= 0) if (r <= 0)
continue; continue;
send_to_from(udps, buf, r, 0, &to->u.sa, &from->u.sa, lsa->len); send_to_from(udps, buf, r, 0, &from->u.sa, &to->u.sa, lsa->len);
} }
return 0; return 0;
} }