packet: Move reference count in packet_sock to atomic_long_t
commit db3fadacaf
upstream.
In some potential instances the reference count on struct packet_sock
could be saturated and cause overflows which gets the kernel a bit
confused. To prevent this, move to a 64-bit atomic reference count on
64-bit architectures to prevent the possibility of this type to overflow.
Because we can not handle saturation, using refcount_t is not possible
in this place. Maybe someday in the future if it changes it could be
used. Also, instead of using plain atomic64_t, use atomic_long_t instead.
32-bit machines tend to be memory-limited (i.e. anything that increases
a reference uses so much memory that you can't actually get to 2**32
references). 32-bit architectures also tend to have serious problems
with 64-bit atomics. Hence, atomic_long_t is the more natural solution.
Reported-by: "The UK's National Cyber Security Centre (NCSC)" <security@ncsc.gov.uk>
Co-developed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@kernel.org
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20231201131021.19999-1-daniel@iogearbox.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
729721cfbd
commit
17674fbd97
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@ -4252,7 +4252,7 @@ static void packet_mm_open(struct vm_area_struct *vma)
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struct sock *sk = sock->sk;
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if (sk)
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atomic_inc(&pkt_sk(sk)->mapped);
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atomic_long_inc(&pkt_sk(sk)->mapped);
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}
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static void packet_mm_close(struct vm_area_struct *vma)
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@ -4262,7 +4262,7 @@ static void packet_mm_close(struct vm_area_struct *vma)
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struct sock *sk = sock->sk;
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if (sk)
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atomic_dec(&pkt_sk(sk)->mapped);
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atomic_long_dec(&pkt_sk(sk)->mapped);
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}
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static const struct vm_operations_struct packet_mmap_ops = {
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@ -4357,7 +4357,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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err = -EBUSY;
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if (!closing) {
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if (atomic_read(&po->mapped))
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if (atomic_long_read(&po->mapped))
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goto out;
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if (packet_read_pending(rb))
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goto out;
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@ -4460,7 +4460,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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err = -EBUSY;
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mutex_lock(&po->pg_vec_lock);
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if (closing || atomic_read(&po->mapped) == 0) {
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if (closing || atomic_long_read(&po->mapped) == 0) {
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err = 0;
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spin_lock_bh(&rb_queue->lock);
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swap(rb->pg_vec, pg_vec);
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@ -4478,9 +4478,9 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u,
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po->prot_hook.func = (po->rx_ring.pg_vec) ?
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tpacket_rcv : packet_rcv;
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skb_queue_purge(rb_queue);
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if (atomic_read(&po->mapped))
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pr_err("packet_mmap: vma is busy: %d\n",
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atomic_read(&po->mapped));
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if (atomic_long_read(&po->mapped))
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pr_err("packet_mmap: vma is busy: %ld\n",
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atomic_long_read(&po->mapped));
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}
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mutex_unlock(&po->pg_vec_lock);
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@ -4558,7 +4558,7 @@ static int packet_mmap(struct file *file, struct socket *sock,
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}
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}
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atomic_inc(&po->mapped);
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atomic_long_inc(&po->mapped);
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vma->vm_ops = &packet_mmap_ops;
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err = 0;
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@ -125,7 +125,7 @@ struct packet_sock {
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__be16 num;
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struct packet_rollover *rollover;
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struct packet_mclist *mclist;
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atomic_t mapped;
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atomic_long_t mapped;
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enum tpacket_versions tp_version;
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unsigned int tp_hdrlen;
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unsigned int tp_reserve;
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