From 448a5ce1120c5bdbce1f1ccdabcd31c7d029f328 Mon Sep 17 00:00:00 2001 From: Vladislav Efanov Date: Tue, 30 May 2023 14:39:41 +0300 Subject: udp6: Fix race condition in udp6_sendmsg & connect Syzkaller got the following report: BUG: KASAN: use-after-free in sk_setup_caps+0x621/0x690 net/core/sock.c:2018 Read of size 8 at addr ffff888027f82780 by task syz-executor276/3255 The function sk_setup_caps (called by ip6_sk_dst_store_flow-> ip6_dst_store) referenced already freed memory as this memory was freed by parallel task in udpv6_sendmsg->ip6_sk_dst_lookup_flow-> sk_dst_check. task1 (connect) task2 (udp6_sendmsg) sk_setup_caps->sk_dst_set | | sk_dst_check-> | sk_dst_set | dst_release sk_setup_caps references | to already freed dst_entry| The reason for this race condition is: sk_setup_caps() keeps using the dst after transferring the ownership to the dst cache. Found by Linux Verification Center (linuxtesting.org) with syzkaller. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Vladislav Efanov Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/core/sock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net/core') diff --git a/net/core/sock.c b/net/core/sock.c index 5440e67bcfe3..24f2761bdb1d 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2381,7 +2381,6 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst) { u32 max_segs = 1; - sk_dst_set(sk, dst); sk->sk_route_caps = dst->dev->features; if (sk_is_tcp(sk)) sk->sk_route_caps |= NETIF_F_GSO; @@ -2400,6 +2399,7 @@ void sk_setup_caps(struct sock *sk, struct dst_entry *dst) } } sk->sk_gso_max_segs = max_segs; + sk_dst_set(sk, dst); } EXPORT_SYMBOL_GPL(sk_setup_caps); -- cgit v1.2.3 From b0ad3c179059089d809b477a1d445c1183a7b8fe Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 31 May 2023 12:01:42 -0400 Subject: rtnetlink: call validate_linkmsg in rtnl_create_link validate_linkmsg() was introduced by commit 1840bb13c22f5b ("[RTNL]: Validate hardware and broadcast address attribute for RTM_NEWLINK") to validate tb[IFLA_ADDRESS/BROADCAST] for existing links. The same check should also be done for newly created links. This patch adds validate_linkmsg() call in rtnl_create_link(), to avoid the invalid address set when creating some devices like: # ip link add dummy0 type dummy # ip link add link dummy0 name mac0 address 01:02 type macsec Fixes: 0e06877c6fdb ("[RTNETLINK]: rtnl_link: allow specifying initial device address") Signed-off-by: Xin Long Reviewed-by: Simon Horman Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'net/core') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 653901a1bf75..824688edb722 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3285,6 +3285,7 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname, struct net_device *dev; unsigned int num_tx_queues = 1; unsigned int num_rx_queues = 1; + int err; if (tb[IFLA_NUM_TX_QUEUES]) num_tx_queues = nla_get_u32(tb[IFLA_NUM_TX_QUEUES]); @@ -3320,13 +3321,18 @@ struct net_device *rtnl_create_link(struct net *net, const char *ifname, if (!dev) return ERR_PTR(-ENOMEM); + err = validate_linkmsg(dev, tb, extack); + if (err < 0) { + free_netdev(dev); + return ERR_PTR(err); + } + dev_net_set(dev, net); dev->rtnl_link_ops = ops; dev->rtnl_link_state = RTNL_LINK_INITIALIZING; if (tb[IFLA_MTU]) { u32 mtu = nla_get_u32(tb[IFLA_MTU]); - int err; err = dev_validate_mtu(dev, mtu, extack); if (err) { -- cgit v1.2.3 From fef5b228dd38378148bc850f7e69a7783f3b95a4 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 31 May 2023 12:01:43 -0400 Subject: rtnetlink: move IFLA_GSO_ tb check to validate_linkmsg These IFLA_GSO_* tb check should also be done for the new created link, otherwise, they can be set to a huge value when creating links: # ip link add dummy1 gso_max_size 4294967295 type dummy # ip -d link show dummy1 dummy addrgenmode eui64 ... gso_max_size 4294967295 Fixes: 46e6b992c250 ("rtnetlink: allow GSO maximums to be set on device creation") Fixes: 9eefedd58ae1 ("net: add gso_ipv4_max_size and gro_ipv4_max_size per device") Signed-off-by: Xin Long Reviewed-by: Simon Horman Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) (limited to 'net/core') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 824688edb722..bc068a857219 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2385,6 +2385,25 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[], if (tb[IFLA_BROADCAST] && nla_len(tb[IFLA_BROADCAST]) < dev->addr_len) return -EINVAL; + + if (tb[IFLA_GSO_MAX_SIZE] && + nla_get_u32(tb[IFLA_GSO_MAX_SIZE]) > dev->tso_max_size) { + NL_SET_ERR_MSG(extack, "too big gso_max_size"); + return -EINVAL; + } + + if (tb[IFLA_GSO_MAX_SEGS] && + (nla_get_u32(tb[IFLA_GSO_MAX_SEGS]) > GSO_MAX_SEGS || + nla_get_u32(tb[IFLA_GSO_MAX_SEGS]) > dev->tso_max_segs)) { + NL_SET_ERR_MSG(extack, "too big gso_max_segs"); + return -EINVAL; + } + + if (tb[IFLA_GSO_IPV4_MAX_SIZE] && + nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]) > dev->tso_max_size) { + NL_SET_ERR_MSG(extack, "too big gso_ipv4_max_size"); + return -EINVAL; + } } if (tb[IFLA_AF_SPEC]) { @@ -2858,11 +2877,6 @@ static int do_setlink(const struct sk_buff *skb, if (tb[IFLA_GSO_MAX_SIZE]) { u32 max_size = nla_get_u32(tb[IFLA_GSO_MAX_SIZE]); - if (max_size > dev->tso_max_size) { - err = -EINVAL; - goto errout; - } - if (dev->gso_max_size ^ max_size) { netif_set_gso_max_size(dev, max_size); status |= DO_SETLINK_MODIFIED; @@ -2872,11 +2886,6 @@ static int do_setlink(const struct sk_buff *skb, if (tb[IFLA_GSO_MAX_SEGS]) { u32 max_segs = nla_get_u32(tb[IFLA_GSO_MAX_SEGS]); - if (max_segs > GSO_MAX_SEGS || max_segs > dev->tso_max_segs) { - err = -EINVAL; - goto errout; - } - if (dev->gso_max_segs ^ max_segs) { netif_set_gso_max_segs(dev, max_segs); status |= DO_SETLINK_MODIFIED; @@ -2895,11 +2904,6 @@ static int do_setlink(const struct sk_buff *skb, if (tb[IFLA_GSO_IPV4_MAX_SIZE]) { u32 max_size = nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]); - if (max_size > dev->tso_max_size) { - err = -EINVAL; - goto errout; - } - if (dev->gso_ipv4_max_size ^ max_size) { netif_set_gso_ipv4_max_size(dev, max_size); status |= DO_SETLINK_MODIFIED; -- cgit v1.2.3 From 65d6914e253f3d83b724a9bbfc889ae95711e512 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Wed, 31 May 2023 12:01:44 -0400 Subject: rtnetlink: add the missing IFLA_GRO_ tb check in validate_linkmsg This fixes the issue that dev gro_max_size and gso_ipv4_max_size can be set to a huge value: # ip link add dummy1 type dummy # ip link set dummy1 gro_max_size 4294967295 # ip -d link show dummy1 dummy addrgenmode eui64 ... gro_max_size 4294967295 Fixes: 0fe79f28bfaf ("net: allow gro_max_size to exceed 65536") Fixes: 9eefedd58ae1 ("net: add gso_ipv4_max_size and gro_ipv4_max_size per device") Reported-by: Xiumei Mu Signed-off-by: Xin Long Reviewed-by: Simon Horman Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'net/core') diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index bc068a857219..41de3a2f29e1 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2399,11 +2399,23 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[], return -EINVAL; } + if (tb[IFLA_GRO_MAX_SIZE] && + nla_get_u32(tb[IFLA_GRO_MAX_SIZE]) > GRO_MAX_SIZE) { + NL_SET_ERR_MSG(extack, "too big gro_max_size"); + return -EINVAL; + } + if (tb[IFLA_GSO_IPV4_MAX_SIZE] && nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]) > dev->tso_max_size) { NL_SET_ERR_MSG(extack, "too big gso_ipv4_max_size"); return -EINVAL; } + + if (tb[IFLA_GRO_IPV4_MAX_SIZE] && + nla_get_u32(tb[IFLA_GRO_IPV4_MAX_SIZE]) > GRO_MAX_SIZE) { + NL_SET_ERR_MSG(extack, "too big gro_ipv4_max_size"); + return -EINVAL; + } } if (tb[IFLA_AF_SPEC]) { -- cgit v1.2.3