KCSAN reported a data race involving net->xfrm.policy_count access. Add missing READ_ONCE()/WRITE_ONCE() annotations on xfrm_policy_count and xfrm_policy_default. Fixes: 2518c7c2b3d7 ("[XFRM]: Hash policies when non-prefixed.") Reported-by: syzbot+d85ba1c732720b9a4097@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/6a2b9e96.99669fcc.12a77b.0006.GAE@google.com/T/#u Signed-off-by: Eric Dumazet --- Cc: Steffen Klassert Cc: Herbert Xu --- include/net/xfrm.h | 8 ++++---- net/xfrm/xfrm_policy.c | 24 ++++++++++++------------ net/xfrm/xfrm_user.c | 18 +++++++++--------- 3 files changed, 25 insertions(+), 25 deletions(-) diff --git a/include/net/xfrm.h b/include/net/xfrm.h index 874409127e292197c17dbac4686efdd5ff56c185..35a7431293298a9eb7f82c8a865ca45e227e81e1 100644 --- a/include/net/xfrm.h +++ b/include/net/xfrm.h @@ -1250,8 +1250,8 @@ int __xfrm_policy_check(struct sock *, int dir, struct sk_buff *skb, static inline bool __xfrm_check_nopolicy(struct net *net, struct sk_buff *skb, int dir) { - if (!net->xfrm.policy_count[dir] && !secpath_exists(skb)) - return net->xfrm.policy_default[dir] == XFRM_USERPOLICY_ACCEPT; + if (!READ_ONCE(net->xfrm.policy_count[dir]) && !secpath_exists(skb)) + return READ_ONCE(net->xfrm.policy_default[dir]) == XFRM_USERPOLICY_ACCEPT; return false; } @@ -1351,8 +1351,8 @@ static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family) { struct net *net = dev_net(skb->dev); - if (!net->xfrm.policy_count[XFRM_POLICY_OUT] && - net->xfrm.policy_default[XFRM_POLICY_OUT] == XFRM_USERPOLICY_ACCEPT) + if (!READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_OUT]) && + READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_OUT]) == XFRM_USERPOLICY_ACCEPT) return true; return (skb_dst(skb)->flags & DST_NOXFRM) || diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 95954442569290719b9fdb7b0f9462d70b5d755e..1f4afd580105f97094c6ad8d10001912f67cc731 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -685,7 +685,7 @@ static void xfrm_byidx_resize(struct net *net) static inline int xfrm_bydst_should_resize(struct net *net, int dir, int *total) { - unsigned int cnt = net->xfrm.policy_count[dir]; + unsigned int cnt = READ_ONCE(net->xfrm.policy_count[dir]); unsigned int hmask = net->xfrm.policy_bydst[dir].hmask; if (total) @@ -711,12 +711,12 @@ static inline int xfrm_byidx_should_resize(struct net *net, int total) void xfrm_spd_getinfo(struct net *net, struct xfrmk_spdinfo *si) { - si->incnt = net->xfrm.policy_count[XFRM_POLICY_IN]; - si->outcnt = net->xfrm.policy_count[XFRM_POLICY_OUT]; - si->fwdcnt = net->xfrm.policy_count[XFRM_POLICY_FWD]; - si->inscnt = net->xfrm.policy_count[XFRM_POLICY_IN+XFRM_POLICY_MAX]; - si->outscnt = net->xfrm.policy_count[XFRM_POLICY_OUT+XFRM_POLICY_MAX]; - si->fwdscnt = net->xfrm.policy_count[XFRM_POLICY_FWD+XFRM_POLICY_MAX]; + si->incnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_IN]); + si->outcnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_OUT]); + si->fwdcnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_FWD]); + si->inscnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_IN+XFRM_POLICY_MAX]); + si->outscnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_OUT+XFRM_POLICY_MAX]); + si->fwdscnt = READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_FWD+XFRM_POLICY_MAX]); si->spdhcnt = net->xfrm.policy_idx_hmask; si->spdhmcnt = xfrm_policy_hashmax; } @@ -2318,7 +2318,7 @@ static void __xfrm_policy_link(struct xfrm_policy *pol, int dir) } list_add(&pol->walk.all, &net->xfrm.policy_all); - net->xfrm.policy_count[dir]++; + WRITE_ONCE(net->xfrm.policy_count[dir], net->xfrm.policy_count[dir] + 1); xfrm_pol_hold(pol); } @@ -2337,7 +2337,7 @@ static struct xfrm_policy *__xfrm_policy_unlink(struct xfrm_policy *pol, } list_del_init(&pol->walk.all); - net->xfrm.policy_count[dir]--; + WRITE_ONCE(net->xfrm.policy_count[dir], net->xfrm.policy_count[dir] - 1); return pol; } @@ -3222,7 +3222,7 @@ struct dst_entry *xfrm_lookup_with_ifid(struct net *net, /* To accelerate a bit... */ if (!if_id && ((dst_orig->flags & DST_NOXFRM) || - !net->xfrm.policy_count[XFRM_POLICY_OUT])) + !READ_ONCE(net->xfrm.policy_count[XFRM_POLICY_OUT]))) goto nopol; xdst = xfrm_bundle_lookup(net, fl, family, dir, &xflo, if_id); @@ -3296,7 +3296,7 @@ struct dst_entry *xfrm_lookup_with_ifid(struct net *net, nopol: if ((!dst_orig->dev || !(dst_orig->dev->flags & IFF_LOOPBACK)) && - net->xfrm.policy_default[dir] == XFRM_USERPOLICY_BLOCK) { + READ_ONCE(net->xfrm.policy_default[dir]) == XFRM_USERPOLICY_BLOCK) { err = -EPERM; goto error; } @@ -3750,7 +3750,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, const bool is_crypto_offload = sp && (xfrm_input_state(skb)->xso.type == XFRM_DEV_OFFLOAD_CRYPTO); - if (net->xfrm.policy_default[dir] == XFRM_USERPOLICY_BLOCK) { + if (READ_ONCE(net->xfrm.policy_default[dir]) == XFRM_USERPOLICY_BLOCK) { XFRM_INC_STATS(net, LINUX_MIB_XFRMINNOPOLS); return 0; } diff --git a/net/xfrm/xfrm_user.c b/net/xfrm/xfrm_user.c index 71a4b7278eba92a7014f877428a587587d0fd476..8de2ebb0f9d7940b28802fc1421f21312df698fe 100644 --- a/net/xfrm/xfrm_user.c +++ b/net/xfrm/xfrm_user.c @@ -2485,9 +2485,9 @@ static int xfrm_notify_userpolicy(struct net *net) } up = nlmsg_data(nlh); - up->in = net->xfrm.policy_default[XFRM_POLICY_IN]; - up->fwd = net->xfrm.policy_default[XFRM_POLICY_FWD]; - up->out = net->xfrm.policy_default[XFRM_POLICY_OUT]; + up->in = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_IN]); + up->fwd = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_FWD]); + up->out = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_OUT]); nlmsg_end(skb, nlh); @@ -2511,13 +2511,13 @@ static int xfrm_set_default(struct sk_buff *skb, struct nlmsghdr *nlh, struct xfrm_userpolicy_default *up = nlmsg_data(nlh); if (xfrm_userpolicy_is_valid(up->in)) - net->xfrm.policy_default[XFRM_POLICY_IN] = up->in; + WRITE_ONCE(net->xfrm.policy_default[XFRM_POLICY_IN], up->in); if (xfrm_userpolicy_is_valid(up->fwd)) - net->xfrm.policy_default[XFRM_POLICY_FWD] = up->fwd; + WRITE_ONCE(net->xfrm.policy_default[XFRM_POLICY_FWD], up->fwd); if (xfrm_userpolicy_is_valid(up->out)) - net->xfrm.policy_default[XFRM_POLICY_OUT] = up->out; + WRITE_ONCE(net->xfrm.policy_default[XFRM_POLICY_OUT], up->out); rt_genid_bump_all(net); @@ -2547,9 +2547,9 @@ static int xfrm_get_default(struct sk_buff *skb, struct nlmsghdr *nlh, } r_up = nlmsg_data(r_nlh); - r_up->in = net->xfrm.policy_default[XFRM_POLICY_IN]; - r_up->fwd = net->xfrm.policy_default[XFRM_POLICY_FWD]; - r_up->out = net->xfrm.policy_default[XFRM_POLICY_OUT]; + r_up->in = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_IN]); + r_up->fwd = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_FWD]); + r_up->out = READ_ONCE(net->xfrm.policy_default[XFRM_POLICY_OUT]); nlmsg_end(r_skb, r_nlh); return nlmsg_unicast(xfrm_net_nlsk(net, skb), r_skb, portid); -- 2.54.0.1136.gdb2ca164c4-goog