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[3.4 backport] Fix heap-use-after-free in free_fast_fallback_getaddrinfo_entry #13652

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Merged
k0kubun merged 2 commits into from
Jun 18, 2025
Merged

[3.4 backport] Fix heap-use-after-free in free_fast_fallback_getaddrinfo_entry #13652

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e3f630a
Ensure that memory is not freed before calling `free_fast_fallback_ge…
shioimm Jan 29, 2025
13c96cb
Fix `heap-use-after-free` in `free_fast_fallback_getaddrinfo_entry` (…
shioimm May 3, 2025
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18 changes: 13 additions & 5 deletions ext/socket/ipsocket.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1159,13 +1159,19 @@ fast_fallback_inetsock_cleanup(VALUE v)
getaddrinfo_shared->notify = -1;

int shared_need_free = 0;
int need_free[2] = { 0, 0 };
struct addrinfo *ais[arg->family_size];
for (int i = 0; i < arg->family_size; i++) ais[i] = NULL;

rb_nativethread_lock_lock(&getaddrinfo_shared->lock);
{
for (int i = 0; i < arg->family_size; i++) {
if (arg->getaddrinfo_entries[i] && --(arg->getaddrinfo_entries[i]->refcount) == 0) {
need_free[i] = 1;
struct fast_fallback_getaddrinfo_entry *getaddrinfo_entry = arg->getaddrinfo_entries[i];

if (!getaddrinfo_entry) continue;

if (--(getaddrinfo_entry->refcount) == 0) {
ais[i] = getaddrinfo_entry->ai;
getaddrinfo_entry->ai = NULL;
}
}
if (--(getaddrinfo_shared->refcount) == 0) {
Expand All @@ -1175,9 +1181,11 @@ fast_fallback_inetsock_cleanup(VALUE v)
rb_nativethread_lock_unlock(&getaddrinfo_shared->lock);

for (int i = 0; i < arg->family_size; i++) {
if (need_free[i]) free_fast_fallback_getaddrinfo_entry(&arg->getaddrinfo_entries[i]);
if (ais[i]) freeaddrinfo(ais[i]);
}
if (getaddrinfo_shared && shared_need_free) {
free_fast_fallback_getaddrinfo_shared(&getaddrinfo_shared);
}
if (shared_need_free) free_fast_fallback_getaddrinfo_shared(&getaddrinfo_shared);
}

int connection_attempt_fd;
Expand Down
22 changes: 7 additions & 15 deletions ext/socket/raddrinfo.c
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Original file line number Diff line number Diff line change
Expand Up @@ -3038,22 +3038,13 @@ free_fast_fallback_getaddrinfo_shared(struct fast_fallback_getaddrinfo_shared **
*shared = NULL;
}

void
free_fast_fallback_getaddrinfo_entry(struct fast_fallback_getaddrinfo_entry **entry)
{
if ((*entry)->ai) {
freeaddrinfo((*entry)->ai);
(*entry)->ai = NULL;
}
*entry = NULL;
}

static void *
do_fast_fallback_getaddrinfo(void *ptr)
{
struct fast_fallback_getaddrinfo_entry *entry = (struct fast_fallback_getaddrinfo_entry *)ptr;
struct fast_fallback_getaddrinfo_shared *shared = entry->shared;
int err = 0, need_free = 0, shared_need_free = 0;
int err = 0, shared_need_free = 0;
struct addrinfo *ai = NULL;

sigset_t set;
sigemptyset(&set);
Expand Down Expand Up @@ -3102,14 +3093,15 @@ do_fast_fallback_getaddrinfo(void *ptr)
entry->err = errno;
entry->has_syserr = true;
}
if (--(entry->refcount) == 0) need_free = 1;
if (--(entry->refcount) == 0) {
ai = entry->ai;
entry->ai = NULL;
}
if (--(shared->refcount) == 0) shared_need_free = 1;
}
rb_nativethread_lock_unlock(&shared->lock);

if (need_free && entry) {
free_fast_fallback_getaddrinfo_entry(&entry);
}
if (ai) freeaddrinfo(ai);
if (shared_need_free && shared) {
free_fast_fallback_getaddrinfo_shared(&shared);
}
Expand Down
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