From: Zhiling Zou <zhilinz@nebusec.ai> mainline inclusion from mainline-v7.2-rc7 commit 653d7ddf6cba867777a3d14c4f83ace008c5ad13 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18205 CVE: CVE-2026-74662 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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: stable@vger.kernel.org Reported-by: Vega <vega@nebusec.ai> Signed-off-by: Zhiling Zou <zhilinz@nebusec.ai> Signed-off-by: Ren Wei <enjou1224z@gmail.com> Link: https://patch.msgid.link/bf66785e7c0c139d7a1900e2f01faeeab344b960.1784948849... Signed-off-by: Jakub Kicinski <kuba@kernel.org> Conflicts: net/ipv4/inet_fragment.c [4.19 use struct netns_frags *nf (not struct fqdir *fqdir) and have no inet_frag_putn(); inet_frag_kill() takes a single argument. The conflict error path keeps the target's inet_frag_kill(q) + inet_frag_destroy(q) cleanup instead of upstream's inet_frag_putn(q, 2). The fix semantics are preserved: the queue is published into the rhashtable before the timer is armed, both under q->lock.] Signed-off-by: JiangJieHua <jiangjiehua1@huawei.com> --- net/ipv4/inet_fragment.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/net/ipv4/inet_fragment.c b/net/ipv4/inet_fragment.c index 5d004c3f4e2b0..4f2118c7f3db6 100644 --- a/net/ipv4/inet_fragment.c +++ b/net/ipv4/inet_fragment.c @@ -270,16 +270,19 @@ static struct inet_frag_queue *inet_frag_create(struct netns_frags *nf, *prev = ERR_PTR(-ENOMEM); return NULL; } - mod_timer(&q->timer, jiffies + nf->timeout); + spin_lock_bh(&q->lock); *prev = rhashtable_lookup_get_insert_key(&nf->rhashtable, &q->key, &q->node, f->rhash_params); if (*prev) { q->flags |= INET_FRAG_COMPLETE; + spin_unlock_bh(&q->lock); inet_frag_kill(q); inet_frag_destroy(q); return NULL; } + mod_timer(&q->timer, jiffies + nf->timeout); + spin_unlock_bh(&q->lock); return q; } -- 2.33.8