[PATCH 6.6.y 5/5] inet: frags: publish queues before arming timer
Sasha Levin <[email protected]>
| Newsgroups | org.kernel.vger.stable |
|---|---|
| Message-ID | <[email protected]> |
From: Zhiling Zou <[email protected]> [ Upstream commit 653d7ddf6cba867777a3d14c4f83ace008c5ad13 ] inet_frag_create() arms the fragment queue timer before inserting the queue into the fqdir rhashtable. If the namespace fragment timeout is zero or negative, the timer can run before the queue is published. The timer callback then marks the queue complete, tries to remove a node that is not in the hash table yet, and drops the anticipated hash reference. Creation can subsequently publish the completed queue without restoring that reference, leaving a stale hash node after the caller drops the remaining reference. Publish the queue first and arm the timer while holding the queue lock. This makes timer expiry wait until the queue is visible in the hash table, so inet_frag_kill() can remove the node and balance the hash reference. Fixes: 648700f76b03 ("inet: frags: use rhashtables for reassembly units") Cc: [email protected] Reported-by: Vega <[email protected]> Signed-off-by: Zhiling Zou <[email protected]> Signed-off-by: Ren Wei <[email protected]> Link: https://patch.msgid.link/bf66785e7c0c139d7a1900e2f01faeeab344b960.1784948849.git.zhilinz@nebusec.ai Signed-off-by: Jakub Kicinski <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- net/ipv4/inet_fragment.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index e5b03de2f6afc..1299413bc9804 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -393,8 +393,8 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, *prev = ERR_PTR(-ENOMEM); return NULL; } - mod_timer(&q->timer, jiffies + fqdir->timeout); + spin_lock_bh(&q->lock); *prev = rhashtable_lookup_get_insert_key(&fqdir->rhashtable, &q->key, &q->node, f->rhash_params); if (*prev) { @@ -402,13 +402,13 @@ static struct inet_frag_queue *inet_frag_create(struct fqdir *fqdir, * we need to cancel what inet_frag_alloc() * anticipated. */ - int refs = 1; - q->flags |= INET_FRAG_COMPLETE; - inet_frag_kill(q, &refs); - inet_frag_putn(q, refs); + spin_unlock_bh(&q->lock); + inet_frag_putn(q, 2); return NULL; } + mod_timer(&q->timer, jiffies + fqdir->timeout); + spin_unlock_bh(&q->lock); return q; } -- 2.53.0