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Diffstat (limited to 'libc/inet')
-rw-r--r--libc/inet/resolv.c72
1 files changed, 39 insertions, 33 deletions
diff --git a/libc/inet/resolv.c b/libc/inet/resolv.c
index ce19c8698..7bc46f227 100644
--- a/libc/inet/resolv.c
+++ b/libc/inet/resolv.c
@@ -398,6 +398,10 @@ int attribute_hidden __encode_dotted(const char *dotted, unsigned char *dest, in
char *c = strchr(dotted, '.');
int l = c ? c - dotted : strlen(dotted);
+ /* two consecutive dots are not valid */
+ if (l == 0)
+ return -1;
+
if (l >= (maxlen - used - 1))
return -1;
@@ -746,8 +750,9 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
unsigned retries = 0;
unsigned char * packet = malloc(PACKETSZ);
char *dns, *lookup = malloc(MAXDNAME);
- int variant = -1;
+ int variant = -1; /* search domain to append, -1 - none */
int local_ns = -1, local_id = -1;
+ bool ends_with_dot;
#ifdef __UCLIBC_HAS_IPV6__
bool v6;
struct sockaddr_in6 sa6;
@@ -758,11 +763,13 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
fd = -1;
- if (!packet || !lookup || !nscount)
+ if (!packet || !lookup || !nscount || !name[0])
goto fail;
DPRINTF("Looking up type %d answer for '%s'\n", type, name);
+ ends_with_dot = (name[strlen(name) - 1] == '.');
+
/* Mess with globals while under lock */
__UCLIBC_MUTEX_LOCK(mylock);
local_ns = static_ns % nscount;
@@ -780,12 +787,6 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
++local_id;
local_id &= 0xffff;
h.id = local_id;
- __UCLIBC_MUTEX_LOCK(__resolv_lock);
- /* this is really __nameserver[] which is a global that
- needs to hold __resolv_lock before access!! */
- dns = nsip[local_ns];
- __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
-
h.qdcount = 1;
h.rd = 1;
@@ -796,14 +797,23 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
goto fail;
strncpy(lookup, name, MAXDNAME);
+ __UCLIBC_MUTEX_LOCK(__resolv_lock);
+ /* nsip is really __nameserver[] which is a global that
+ needs to hold __resolv_lock before access!! */
+ dns = nsip[local_ns];
+/* TODO: all future accesses to 'dns' are guarded by __resolv_lock too.
+ * Why? We already fetched nsip[local_ns] here,
+ * future changes to nsip[] by other threads cannot affect us.
+ * We can use 'dns' without locking. If I'm wrong,
+ * please explain in comments why locking is needed. */
if (variant >= 0) {
- __UCLIBC_MUTEX_LOCK(__resolv_lock);
if (variant < __searchdomains) {
strncat(lookup, ".", MAXDNAME);
strncat(lookup, __searchdomain[variant], MAXDNAME);
}
- __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
}
+ __UCLIBC_MUTEX_UNLOCK(__resolv_lock);
+
DPRINTF("lookup name: %s\n", lookup);
q.dotted = (char *)lookup;
q.qtype = type;
@@ -994,19 +1004,18 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
tryall:
/* if there are other nameservers, give them a go,
otherwise return with error */
- {
- variant = -1;
- local_ns = (local_ns + 1) % nscount;
- if (local_ns == 0)
- retries++;
+ variant = -1;
+ local_ns = (local_ns + 1) % nscount;
+ if (local_ns == 0)
+ retries++;
- continue;
- }
+ continue;
again:
/* if there are searchdomains, try them or fallback as passed */
- {
+ if (!ends_with_dot) {
int sdomains;
+
__UCLIBC_MUTEX_LOCK(__resolv_lock);
sdomains = __searchdomains;
__UCLIBC_MUTEX_UNLOCK(__resolv_lock);
@@ -1014,15 +1023,14 @@ int attribute_hidden __dns_lookup(const char *name, int type, int nscount, char
if (variant < sdomains - 1) {
/* next search */
variant++;
- } else {
- /* next server, first search */
- local_ns = (local_ns + 1) % nscount;
- if (local_ns == 0)
- retries++;
-
- variant = -1;
+ continue;
}
}
+ /* next server, first search */
+ local_ns = (local_ns + 1) % nscount;
+ if (local_ns == 0)
+ retries++;
+ variant = -1;
}
fail:
@@ -1267,10 +1275,10 @@ int res_query(const char *dname, int class, int type,
__open_nameservers();
if (!dname || class != 1 /* CLASS_IN */) {
h_errno = NO_RECOVERY;
- return(-1);
+ return -1;
}
- memset((char *) &a, '\0', sizeof(a));
+ memset(&a, '\0', sizeof(a));
__UCLIBC_MUTEX_LOCK(__resolv_lock);
__nameserversXX = __nameservers;
@@ -1280,16 +1288,14 @@ int res_query(const char *dname, int class, int type,
if (i < 0) {
h_errno = TRY_AGAIN;
- return(-1);
+ return -1;
}
free(a.dotted);
- if (a.atype == type) { /* CNAME*/
- int len = MIN(anslen, i);
- memcpy(answer, packet, len);
- free(packet);
- return(len);
+ if (a.atype == type) { /* CNAME */
+ i = MIN(anslen, i);
+ memcpy(answer, packet, i);
}
free(packet);
return i;