diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-03-12 08:22:49 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2025-03-18 13:18:36 +0100 |
| commit | eb0dfc0ef195a04e519b15d73cf25d8c25ee8df7 (patch) | |
| tree | 48152b079fdd9b88da44c66019531b708507b943 /net/ipv4/inet_fragment.c | |
| parent | a2fb987c0ecf0498cc17056339cb11d128c46ab7 (diff) | |
inet: frags: change inet_frag_kill() to defer refcount updates
In the following patch, we no longer assume inet_frag_kill()
callers own a reference.
Consuming two refcounts from inet_frag_kill() would lead in UAF.
Propagate the pointer to the refs that will be consumed later
by the final inet_frag_putn() call.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250312082250.1803501-4-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/ipv4/inet_fragment.c')
| -rw-r--r-- | net/ipv4/inet_fragment.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index efc4cbee04c2..5eb186050013 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -225,10 +225,10 @@ void fqdir_exit(struct fqdir *fqdir) } EXPORT_SYMBOL(fqdir_exit); -void inet_frag_kill(struct inet_frag_queue *fq) +void inet_frag_kill(struct inet_frag_queue *fq, int *refs) { if (del_timer(&fq->timer)) - refcount_dec(&fq->refcnt); + (*refs)++; if (!(fq->flags & INET_FRAG_COMPLETE)) { struct fqdir *fqdir = fq->fqdir; @@ -243,7 +243,7 @@ void inet_frag_kill(struct inet_frag_queue *fq) if (!READ_ONCE(fqdir->dead)) { rhashtable_remove_fast(&fqdir->rhashtable, &fq->node, fqdir->f->rhash_params); - refcount_dec(&fq->refcnt); + (*refs)++; } else { fq->flags |= INET_FRAG_HASH_DEAD; } @@ -349,9 +349,11 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key, &q->node, f->rhash_params); if (*prev) { + int refs = 2; + q->flags |= INET_FRAG_COMPLETE; - inet_frag_kill(q); - inet_frag_destroy(q); + inet_frag_kill(q, &refs); + inet_frag_putn(q, refs); return NULL; } return q; |