From: Eric Dumazet edumazet@google.com
[ Upstream commit ee5675ecdf7a4e713ed21d98a70c2871d6ebed01 ]
syzbot/KCAN reported that po->origdev can be read while another thread is changing its value.
We can avoid this splat by converting this field to an actual bit.
Following patches will convert remaining 1bit fields.
Fixes: 80feaacb8a64 ("[AF_PACKET]: Add option to return orig_dev to userspace.") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- net/packet/af_packet.c | 10 ++++------ net/packet/diag.c | 2 +- net/packet/internal.h | 22 +++++++++++++++++++++- 3 files changed, 26 insertions(+), 8 deletions(-)
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 1be5fb6af0178..ce6afdb50933b 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2144,7 +2144,7 @@ static int packet_rcv(struct sk_buff *skb, struct net_device *dev, sll = &PACKET_SKB_CB(skb)->sa.ll; sll->sll_hatype = dev->type; sll->sll_pkttype = skb->pkt_type; - if (unlikely(po->origdev)) + if (unlikely(packet_sock_flag(po, PACKET_SOCK_ORIGDEV))) sll->sll_ifindex = orig_dev->ifindex; else sll->sll_ifindex = dev->ifindex; @@ -2410,7 +2410,7 @@ static int tpacket_rcv(struct sk_buff *skb, struct net_device *dev, sll->sll_hatype = dev->type; sll->sll_protocol = skb->protocol; sll->sll_pkttype = skb->pkt_type; - if (unlikely(po->origdev)) + if (unlikely(packet_sock_flag(po, PACKET_SOCK_ORIGDEV))) sll->sll_ifindex = orig_dev->ifindex; else sll->sll_ifindex = dev->ifindex; @@ -3879,9 +3879,7 @@ packet_setsockopt(struct socket *sock, int level, int optname, char __user *optv if (copy_from_user(&val, optval, sizeof(val))) return -EFAULT;
- lock_sock(sk); - po->origdev = !!val; - release_sock(sk); + packet_sock_flag_set(po, PACKET_SOCK_ORIGDEV, val); return 0; } case PACKET_VNET_HDR: @@ -4014,7 +4012,7 @@ static int packet_getsockopt(struct socket *sock, int level, int optname, val = po->auxdata; break; case PACKET_ORIGDEV: - val = po->origdev; + val = packet_sock_flag(po, PACKET_SOCK_ORIGDEV); break; case PACKET_VNET_HDR: val = po->has_vnet_hdr; diff --git a/net/packet/diag.c b/net/packet/diag.c index 7ef1c881ae741..bf5928e5df035 100644 --- a/net/packet/diag.c +++ b/net/packet/diag.c @@ -24,7 +24,7 @@ static int pdiag_put_info(const struct packet_sock *po, struct sk_buff *nlskb) pinfo.pdi_flags |= PDI_RUNNING; if (po->auxdata) pinfo.pdi_flags |= PDI_AUXDATA; - if (po->origdev) + if (packet_sock_flag(po, PACKET_SOCK_ORIGDEV)) pinfo.pdi_flags |= PDI_ORIGDEV; if (po->has_vnet_hdr) pinfo.pdi_flags |= PDI_VNETHDR; diff --git a/net/packet/internal.h b/net/packet/internal.h index f10294800aafb..f39dcc7608bc6 100644 --- a/net/packet/internal.h +++ b/net/packet/internal.h @@ -115,9 +115,9 @@ struct packet_sock { int copy_thresh; spinlock_t bind_lock; struct mutex pg_vec_lock; + unsigned long flags; unsigned int running; /* bind_lock must be held */ unsigned int auxdata:1, /* writer must hold sock lock */ - origdev:1, has_vnet_hdr:1, tp_loss:1, tp_tx_has_off:1; @@ -142,4 +142,24 @@ static struct packet_sock *pkt_sk(struct sock *sk) return (struct packet_sock *)sk; }
+enum packet_sock_flags { + PACKET_SOCK_ORIGDEV, +}; + +static inline void packet_sock_flag_set(struct packet_sock *po, + enum packet_sock_flags flag, + bool val) +{ + if (val) + set_bit(flag, &po->flags); + else + clear_bit(flag, &po->flags); +} + +static inline bool packet_sock_flag(const struct packet_sock *po, + enum packet_sock_flags flag) +{ + return test_bit(flag, &po->flags); +} + #endif