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hostip.c: fix leak of addrinfo

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When creating a dns entry, the addrinfo is passed into the entry on
success and needed deallocation by the caller on failure.

Change the signature to have Curl_dnscache_mk_entry() *always* take
ownership of the addrinfo, even on failure. Change parameter to address
of pointer so that call always clears it.

This makes the handling of failures to Curl_dnscache_mk_entry() simpler.

Fixes #20465
Closes #20468
This commit is contained in:
Stefan Eissing 2026-01-29 11:59:05 +01:00 • committed by Daniel Stenberg
parent a84b041281
commit ffdbc04c7b
No known key found for this signature in database
GPG key ID: 5CC908FDB71E12C2
5 changed files with 24 additions and 27 deletions
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35
lib/hostip.c
View file

@ -559,20 +559,20 @@ UNITTEST CURLcode Curl_shuffle_addr(struct Curl_easy *data,
struct Curl_dns_entry *
Curl_dnscache_mk_entry(struct Curl_easy *data,
struct Curl_addrinfo *addr,
struct Curl_addrinfo **paddr,
const char *hostname,
size_t hostlen, /* length or zero */
int port,
bool permanent)
{
struct Curl_dns_entry *dns;
struct Curl_dns_entry *dns = NULL;
#ifndef CURL_DISABLE_SHUFFLE_DNS
/* shuffle addresses if requested */
if(data->set.dns_shuffle_addresses) {
CURLcode result = Curl_shuffle_addr(data, &addr);
if(data->set.dns_shuffle_addresses && paddr) {
CURLcode result = Curl_shuffle_addr(data, paddr);
if(result)
return NULL;
goto out;
}
#else
(void)data;
@ -583,10 +583,10 @@ Curl_dnscache_mk_entry(struct Curl_easy *data,
/* Create a new cache entry */
dns = curlx_calloc(1, sizeof(struct Curl_dns_entry) + hostlen);
if(!dns)
return NULL;
goto out;
dns->refcount = 1; /* the cache has the first reference */
dns->addr = addr; /* this is the address(es) */
dns->addr = paddr ? *paddr : NULL; /* this is the address(es) */
if(permanent) {
dns->timestamp.tv_sec = 0; /* an entry that never goes stale */
dns->timestamp.tv_usec = 0; /* an entry that never goes stale */
@ -598,13 +598,19 @@ Curl_dnscache_mk_entry(struct Curl_easy *data,
if(hostlen)
memcpy(dns->hostname, hostname, hostlen);
out:
if(paddr) {
if(!dns)
Curl_freeaddrinfo(*paddr);
*paddr = NULL;
}
return dns;
}
static struct Curl_dns_entry *
dnscache_add_addr(struct Curl_easy *data,
struct Curl_dnscache *dnscache,
struct Curl_addrinfo *addr,
struct Curl_addrinfo **paddr,
const char *hostname,
size_t hlen, /* length or zero */
int port,
@ -615,7 +621,7 @@ dnscache_add_addr(struct Curl_easy *data,
struct Curl_dns_entry *dns;
struct Curl_dns_entry *dns2;
dns = Curl_dnscache_mk_entry(data, addr, hostname, hlen, port, permanent);
dns = Curl_dnscache_mk_entry(data, paddr, hostname, hlen, port, permanent);
if(!dns)
return NULL;
@ -627,7 +633,6 @@ dnscache_add_addr(struct Curl_easy *data,
dns2 = Curl_hash_add(&dnscache->entries, entry_id, entry_len + 1,
(void *)dns);
if(!dns2) {
dns->addr = NULL;
dnscache_entry_free(dns);
return NULL;
}
@ -977,13 +982,9 @@ out:
}
else if(addr) {
/* we got a response, create a dns entry, add to cache, return */
dns = Curl_dnscache_mk_entry(data, addr, hostname, 0, port, FALSE);
dns = Curl_dnscache_mk_entry(data, &addr, hostname, 0, port, FALSE);
if(!dns || Curl_dnscache_add(data, dns)) {
/* this is OOM or similar, do not store such negative resolves */
Curl_freeaddrinfo(addr);
if(dns)
/* avoid a dangling pointer to addr in the dying dns entry */
dns->addr = NULL;
result = CURLE_OUT_OF_MEMORY;
goto error;
}
@ -1442,14 +1443,12 @@ err:
}
/* put this new host in the cache */
dns = dnscache_add_addr(data, dnscache, head, curlx_str(&source),
dns = dnscache_add_addr(data, dnscache, &head, curlx_str(&source),
curlx_strlen(&source), (int)port, permanent);
if(dns)
/* release the returned reference; the cache itself will keep the
* entry alive: */
dns->refcount--;
else
Curl_freeaddrinfo(head);
dnscache_unlock(data, dnscache);