Revert struct sockaddr from flexible array to fixed 14-byte "sa_data", solves over 36,000 -Wflex-array-member-not-at-end warnings, since struct sockaddr is embedded within many network structs.
With socket/proto sockaddr-based internal APIs switched to use struct sockaddr_unspec, there should be no more uses of struct sockaddr that depend on reading beyond the end of struct sockaddr::sa_data that might trigger bounds checking. Comparing an x86_64 "allyesconfig" vmlinux build before and after this patch showed no new "ud1" instructions from CONFIG_UBSAN_BOUNDS nor any explicit "field-spanning" memcpy CONFIG_FORTIFY_SOURCE instrumentations. Cc: "Gustavo A. R. Silva" <[email protected]> Signed-off-by: Kees Cook <[email protected]> --- include/linux/socket.h | 6 ++---- tools/perf/trace/beauty/include/linux/socket.h | 5 +---- net/core/dev.c | 2 +- net/core/dev_ioctl.c | 2 +- net/ipv4/arp.c | 2 +- net/packet/af_packet.c | 10 +++++----- 6 files changed, 11 insertions(+), 16 deletions(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 27f57c7ee02a..5e9d83cec850 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -32,12 +32,10 @@ typedef __kernel_sa_family_t sa_family_t; * 1003.1g requires sa_family_t and that sa_data is char. */ +/* Deprecated for in-kernel use. Use struct sockaddr_unspec instead. */ struct sockaddr { sa_family_t sa_family; /* address family, AF_xxx */ - union { - char sa_data_min[14]; /* Minimum 14 bytes of protocol address */ - DECLARE_FLEX_ARRAY(char, sa_data); - }; + char sa_data[14]; /* 14 bytes of protocol address */ }; /** diff --git a/tools/perf/trace/beauty/include/linux/socket.h b/tools/perf/trace/beauty/include/linux/socket.h index 3b262487ec06..77d7c59f5d8b 100644 --- a/tools/perf/trace/beauty/include/linux/socket.h +++ b/tools/perf/trace/beauty/include/linux/socket.h @@ -34,10 +34,7 @@ typedef __kernel_sa_family_t sa_family_t; struct sockaddr { sa_family_t sa_family; /* address family, AF_xxx */ - union { - char sa_data_min[14]; /* Minimum 14 bytes of protocol address */ - DECLARE_FLEX_ARRAY(char, sa_data); - }; + char sa_data[14]; /* 14 bytes of protocol address */ }; struct linger { diff --git a/net/core/dev.c b/net/core/dev.c index a64cef2c537e..6dc5861f87b0 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -9885,7 +9885,7 @@ DECLARE_RWSEM(dev_addr_sem); /* "sa" is a true struct sockaddr with limited "sa_data" member. */ int netif_get_mac_address(struct sockaddr *sa, struct net *net, char *dev_name) { - size_t size = sizeof(sa->sa_data_min); + size_t size = sizeof(sa->sa_data); struct net_device *dev; int ret = 0; diff --git a/net/core/dev_ioctl.c b/net/core/dev_ioctl.c index ad54b12d4b4c..b3ce0fb24a69 100644 --- a/net/core/dev_ioctl.c +++ b/net/core/dev_ioctl.c @@ -596,7 +596,7 @@ static int dev_ifsioc(struct net *net, struct ifreq *ifr, void __user *data, if (ifr->ifr_hwaddr.sa_family != dev->type) return -EINVAL; memcpy(dev->broadcast, ifr->ifr_hwaddr.sa_data, - min(sizeof(ifr->ifr_hwaddr.sa_data_min), + min(sizeof(ifr->ifr_hwaddr.sa_data), (size_t)dev->addr_len)); netdev_lock_ops(dev); call_netdevice_notifiers(NETDEV_CHANGEADDR, dev); diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 833f2cf97178..8316ca59088a 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1189,7 +1189,7 @@ static int arp_req_get(struct net *net, struct arpreq *r) read_lock_bh(&neigh->lock); memcpy(r->arp_ha.sa_data, neigh->ha, - min(dev->addr_len, sizeof(r->arp_ha.sa_data_min))); + min(dev->addr_len, sizeof(r->arp_ha.sa_data))); r->arp_flags = arp_state_to_flags(neigh); read_unlock_bh(&neigh->lock); diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 73bea76ea45d..d21483cae94f 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3284,7 +3284,7 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr_unspec *uaddr, { struct sock *sk = sock->sk; struct sockaddr *sa = (struct sockaddr *)uaddr; - char name[sizeof(sa->sa_data_min) + 1]; + char name[sizeof(sa->sa_data) + 1]; /* * Check legality @@ -3295,8 +3295,8 @@ static int packet_bind_spkt(struct socket *sock, struct sockaddr_unspec *uaddr, /* uaddr->sa_data comes from the userspace, it's not guaranteed to be * zero-terminated. */ - memcpy(name, sa->sa_data, sizeof(sa->sa_data_min)); - name[sizeof(sa->sa_data_min)] = 0; + memcpy(name, sa->sa_data, sizeof(sa->sa_data)); + name[sizeof(sa->sa_data)] = 0; return packet_do_bind(sk, name, 0, 0); } @@ -3581,11 +3581,11 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr, return -EOPNOTSUPP; uaddr->sa_family = AF_PACKET; - memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data_min)); + memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data)); rcu_read_lock(); dev = dev_get_by_index_rcu(sock_net(sk), READ_ONCE(pkt_sk(sk)->ifindex)); if (dev) - strscpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data_min)); + strscpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data)); rcu_read_unlock(); return sizeof(*uaddr); -- 2.34.1
