diff options
Diffstat (limited to 'net/netlink')
-rw-r--r-- | net/netlink/genetlink.c | 340 |
1 files changed, 193 insertions, 147 deletions
diff --git a/net/netlink/genetlink.c b/net/netlink/genetlink.c index f54215d..7dbc4f7 100644 --- a/net/netlink/genetlink.c +++ b/net/netlink/genetlink.c @@ -65,12 +65,24 @@ static struct list_head family_ht[GENL_FAM_TAB_SIZE]; * To avoid an allocation at boot of just one unsigned long, * declare it global instead. * Bit 0 is marked as already used since group 0 is invalid. + * Bit 1 is marked as already used since the drop-monitor code + * abuses the API and thinks it can statically use group 1. + * That group will typically conflict with other groups that + * any proper users use. + * Bit 16 is marked as used since it's used for generic netlink + * and the code no longer marks pre-reserved IDs as used. + * Bit 17 is marked as already used since the VFS quota code + * also abused this API and relied on family == group ID, we + * cater to that by giving it a static family and group ID. */ -static unsigned long mc_group_start = 0x1; +static unsigned long mc_group_start = 0x3 | BIT(GENL_ID_CTRL) | + BIT(GENL_ID_VFS_DQUOT); static unsigned long *mc_groups = &mc_group_start; static unsigned long mc_groups_longs = 1; -static int genl_ctrl_event(int event, void *data); +static int genl_ctrl_event(int event, struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id); static inline unsigned int genl_family_hash(unsigned int id) { @@ -126,7 +138,8 @@ static u16 genl_generate_id(void) int i; for (i = 0; i <= GENL_MAX_ID - GENL_MIN_ID; i++) { - if (!genl_family_find_byid(id_gen_idx)) + if (id_gen_idx != GENL_ID_VFS_DQUOT && + !genl_family_find_byid(id_gen_idx)) return id_gen_idx; if (++id_gen_idx > GENL_MAX_ID) id_gen_idx = GENL_MIN_ID; @@ -135,62 +148,110 @@ static u16 genl_generate_id(void) return 0; } -static struct genl_multicast_group notify_grp; - -/** - * genl_register_mc_group - register a multicast group - * - * Registers the specified multicast group and notifies userspace - * about the new group. - * - * Returns 0 on success or a negative error code. - * - * @family: The generic netlink family the group shall be registered for. - * @grp: The group to register, must have a name. - */ -int genl_register_mc_group(struct genl_family *family, - struct genl_multicast_group *grp) +static int genl_allocate_reserve_groups(int n_groups, int *first_id) { - int id; unsigned long *new_groups; - int err = 0; + int start = 0; + int i; + int id; + bool fits; + + do { + if (start == 0) + id = find_first_zero_bit(mc_groups, + mc_groups_longs * + BITS_PER_LONG); + else + id = find_next_zero_bit(mc_groups, + mc_groups_longs * BITS_PER_LONG, + start); + + fits = true; + for (i = id; + i < min_t(int, id + n_groups, + mc_groups_longs * BITS_PER_LONG); + i++) { + if (test_bit(i, mc_groups)) { + start = i; + fits = false; + break; + } + } - BUG_ON(grp->name[0] == '\0'); - BUG_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL); + if (id >= mc_groups_longs * BITS_PER_LONG) { + unsigned long new_longs = mc_groups_longs + + BITS_TO_LONGS(n_groups); + size_t nlen = new_longs * sizeof(unsigned long); + + if (mc_groups == &mc_group_start) { + new_groups = kzalloc(nlen, GFP_KERNEL); + if (!new_groups) + return -ENOMEM; + mc_groups = new_groups; + *mc_groups = mc_group_start; + } else { + new_groups = krealloc(mc_groups, nlen, + GFP_KERNEL); + if (!new_groups) + return -ENOMEM; + mc_groups = new_groups; + for (i = 0; i < BITS_TO_LONGS(n_groups); i++) + mc_groups[mc_groups_longs + i] = 0; + } + mc_groups_longs = new_longs; + } + } while (!fits); - genl_lock_all(); + for (i = id; i < id + n_groups; i++) + set_bit(i, mc_groups); + *first_id = id; + return 0; +} - /* special-case our own group */ - if (grp == ¬ify_grp) - id = GENL_ID_CTRL; - else - id = find_first_zero_bit(mc_groups, - mc_groups_longs * BITS_PER_LONG); +static struct genl_family genl_ctrl; +static int genl_validate_assign_mc_groups(struct genl_family *family) +{ + int first_id; + int n_groups = family->n_mcgrps; + int err, i; + bool groups_allocated = false; - if (id >= mc_groups_longs * BITS_PER_LONG) { - size_t nlen = (mc_groups_longs + 1) * sizeof(unsigned long); + if (!n_groups) + return 0; - if (mc_groups == &mc_group_start) { - new_groups = kzalloc(nlen, GFP_KERNEL); - if (!new_groups) { - err = -ENOMEM; - goto out; - } - mc_groups = new_groups; - *mc_groups = mc_group_start; - } else { - new_groups = krealloc(mc_groups, nlen, GFP_KERNEL); - if (!new_groups) { - err = -ENOMEM; - goto out; - } - mc_groups = new_groups; - mc_groups[mc_groups_longs] = 0; - } - mc_groups_longs++; + for (i = 0; i < n_groups; i++) { + const struct genl_multicast_group *grp = &family->mcgrps[i]; + + if (WARN_ON(grp->name[0] == '\0')) + return -EINVAL; + if (WARN_ON(memchr(grp->name, '\0', GENL_NAMSIZ) == NULL)) + return -EINVAL; } + /* special-case our own group and hacks */ + if (family == &genl_ctrl) { + first_id = GENL_ID_CTRL; + BUG_ON(n_groups != 1); + } else if (strcmp(family->name, "NET_DM") == 0) { + first_id = 1; + BUG_ON(n_groups != 1); + } else if (strcmp(family->name, "VFS_DQUOT") == 0) { + first_id = GENL_ID_VFS_DQUOT; + BUG_ON(n_groups != 1); + } else { + groups_allocated = true; + err = genl_allocate_reserve_groups(n_groups, &first_id); + if (err) + return err; + } + + family->mcgrp_offset = first_id; + + /* if still initializing, can't and don't need to to realloc bitmaps */ + if (!init_net.genl_sock) + return 0; + if (family->netnsok) { struct net *net; @@ -206,9 +267,7 @@ int genl_register_mc_group(struct genl_family *family, * number of _possible_ groups has been * increased on some sockets which is ok. */ - rcu_read_unlock(); - netlink_table_ungrab(); - goto out; + break; } } rcu_read_unlock(); @@ -216,71 +275,39 @@ int genl_register_mc_group(struct genl_family *family, } else { err = netlink_change_ngroups(init_net.genl_sock, mc_groups_longs * BITS_PER_LONG); - if (err) - goto out; } - grp->id = id; - set_bit(id, mc_groups); - list_add_tail(&grp->list, &family->mcast_groups); - grp->family = family; + if (groups_allocated && err) { + for (i = 0; i < family->n_mcgrps; i++) + clear_bit(family->mcgrp_offset + i, mc_groups); + } - genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, grp); - out: - genl_unlock_all(); return err; } -EXPORT_SYMBOL(genl_register_mc_group); -static void __genl_unregister_mc_group(struct genl_family *family, - struct genl_multicast_group *grp) +static void genl_unregister_mc_groups(struct genl_family *family) { struct net *net; - BUG_ON(grp->family != family); + int i; netlink_table_grab(); rcu_read_lock(); - for_each_net_rcu(net) - __netlink_clear_multicast_users(net->genl_sock, grp->id); + for_each_net_rcu(net) { + for (i = 0; i < family->n_mcgrps; i++) + __netlink_clear_multicast_users( + net->genl_sock, family->mcgrp_offset + i); + } rcu_read_unlock(); netlink_table_ungrab(); - clear_bit(grp->id, mc_groups); - list_del(&grp->list); - genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, grp); - grp->id = 0; - grp->family = NULL; -} - -/** - * genl_unregister_mc_group - unregister a multicast group - * - * Unregisters the specified multicast group and notifies userspace - * about it. All current listeners on the group are removed. - * - * Note: It is not necessary to unregister all multicast groups before - * unregistering the family, unregistering the family will cause - * all assigned multicast groups to be unregistered automatically. - * - * @family: Generic netlink family the group belongs to. - * @grp: The group to unregister, must have been registered successfully - * previously. - */ -void genl_unregister_mc_group(struct genl_family *family, - struct genl_multicast_group *grp) -{ - genl_lock_all(); - __genl_unregister_mc_group(family, grp); - genl_unlock_all(); -} -EXPORT_SYMBOL(genl_unregister_mc_group); - -static void genl_unregister_mc_groups(struct genl_family *family) -{ - struct genl_multicast_group *grp, *tmp; + for (i = 0; i < family->n_mcgrps; i++) { + int grp_id = family->mcgrp_offset + i; - list_for_each_entry_safe(grp, tmp, &family->mcast_groups, list) - __genl_unregister_mc_group(family, grp); + if (grp_id != 1) + clear_bit(grp_id, mc_groups); + genl_ctrl_event(CTRL_CMD_DELMCAST_GRP, family, + &family->mcgrps[i], grp_id); + } } static int genl_validate_ops(struct genl_family *family) @@ -326,7 +353,7 @@ static int genl_validate_ops(struct genl_family *family) */ int __genl_register_family(struct genl_family *family) { - int err = -EINVAL; + int err = -EINVAL, i; if (family->id && family->id < GENL_MIN_ID) goto errout; @@ -338,8 +365,6 @@ int __genl_register_family(struct genl_family *family) if (err) return err; - INIT_LIST_HEAD(&family->mcast_groups); - genl_lock_all(); if (genl_family_find_byname(family->name)) { @@ -371,10 +396,18 @@ int __genl_register_family(struct genl_family *family) } else family->attrbuf = NULL; + err = genl_validate_assign_mc_groups(family); + if (err) + goto errout_locked; + list_add_tail(&family->family_list, genl_family_chain(family->id)); genl_unlock_all(); - genl_ctrl_event(CTRL_CMD_NEWFAMILY, family); + /* send all events */ + genl_ctrl_event(CTRL_CMD_NEWFAMILY, family, NULL, 0); + for (i = 0; i < family->n_mcgrps; i++) + genl_ctrl_event(CTRL_CMD_NEWMCAST_GRP, family, + &family->mcgrps[i], family->mcgrp_offset + i); return 0; @@ -410,7 +443,7 @@ int genl_unregister_family(struct genl_family *family) genl_unlock_all(); kfree(family->attrbuf); - genl_ctrl_event(CTRL_CMD_DELFAMILY, family); + genl_ctrl_event(CTRL_CMD_DELFAMILY, family, NULL, 0); return 0; } @@ -670,23 +703,26 @@ static int ctrl_fill_info(struct genl_family *family, u32 portid, u32 seq, nla_nest_end(skb, nla_ops); } - if (!list_empty(&family->mcast_groups)) { - struct genl_multicast_group *grp; + if (family->n_mcgrps) { struct nlattr *nla_grps; - int idx = 1; + int i; nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); if (nla_grps == NULL) goto nla_put_failure; - list_for_each_entry(grp, &family->mcast_groups, list) { + for (i = 0; i < family->n_mcgrps; i++) { struct nlattr *nest; + const struct genl_multicast_group *grp; + + grp = &family->mcgrps[i]; - nest = nla_nest_start(skb, idx++); + nest = nla_nest_start(skb, i + 1); if (nest == NULL) goto nla_put_failure; - if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || + if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, + family->mcgrp_offset + i) || nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, grp->name)) goto nla_put_failure; @@ -703,9 +739,10 @@ nla_put_failure: return -EMSGSIZE; } -static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid, - u32 seq, u32 flags, struct sk_buff *skb, - u8 cmd) +static int ctrl_fill_mcgrp_info(struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id, u32 portid, u32 seq, u32 flags, + struct sk_buff *skb, u8 cmd) { void *hdr; struct nlattr *nla_grps; @@ -715,8 +752,8 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid, if (hdr == NULL) return -1; - if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, grp->family->name) || - nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, grp->family->id)) + if (nla_put_string(skb, CTRL_ATTR_FAMILY_NAME, family->name) || + nla_put_u16(skb, CTRL_ATTR_FAMILY_ID, family->id)) goto nla_put_failure; nla_grps = nla_nest_start(skb, CTRL_ATTR_MCAST_GROUPS); @@ -727,7 +764,7 @@ static int ctrl_fill_mcgrp_info(struct genl_multicast_group *grp, u32 portid, if (nest == NULL) goto nla_put_failure; - if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp->id) || + if (nla_put_u32(skb, CTRL_ATTR_MCAST_GRP_ID, grp_id) || nla_put_string(skb, CTRL_ATTR_MCAST_GRP_NAME, grp->name)) goto nla_put_failure; @@ -793,8 +830,10 @@ static struct sk_buff *ctrl_build_family_msg(struct genl_family *family, return skb; } -static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, - u32 portid, int seq, u8 cmd) +static struct sk_buff * +ctrl_build_mcgrp_msg(struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id, u32 portid, int seq, u8 cmd) { struct sk_buff *skb; int err; @@ -803,7 +842,8 @@ static struct sk_buff *ctrl_build_mcgrp_msg(struct genl_multicast_group *grp, if (skb == NULL) return ERR_PTR(-ENOBUFS); - err = ctrl_fill_mcgrp_info(grp, portid, seq, 0, skb, cmd); + err = ctrl_fill_mcgrp_info(family, grp, grp_id, portid, + seq, 0, skb, cmd); if (err < 0) { nlmsg_free(skb); return ERR_PTR(err); @@ -865,11 +905,11 @@ static int ctrl_getfamily(struct sk_buff *skb, struct genl_info *info) return genlmsg_reply(msg, info); } -static int genl_ctrl_event(int event, void *data) +static int genl_ctrl_event(int event, struct genl_family *family, + const struct genl_multicast_group *grp, + int grp_id) { struct sk_buff *msg; - struct genl_family *family; - struct genl_multicast_group *grp; /* genl is still initialising */ if (!init_net.genl_sock) @@ -878,14 +918,13 @@ static int genl_ctrl_event(int event, void *data) switch (event) { case CTRL_CMD_NEWFAMILY: case CTRL_CMD_DELFAMILY: - family = data; + WARN_ON(grp); msg = ctrl_build_family_msg(family, 0, 0, event); break; case CTRL_CMD_NEWMCAST_GRP: case CTRL_CMD_DELMCAST_GRP: - grp = data; - family = grp->family; - msg = ctrl_build_mcgrp_msg(data, 0, 0, event); + BUG_ON(!grp); + msg = ctrl_build_mcgrp_msg(family, grp, grp_id, 0, 0, event); break; default: return -EINVAL; @@ -895,26 +934,29 @@ static int genl_ctrl_event(int event, void *data) return PTR_ERR(msg); if (!family->netnsok) { - genlmsg_multicast_netns(&init_net, msg, 0, - GENL_ID_CTRL, GFP_KERNEL); + genlmsg_multicast_netns(&genl_ctrl, &init_net, msg, 0, + 0, GFP_KERNEL); } else { rcu_read_lock(); - genlmsg_multicast_allns(msg, 0, GENL_ID_CTRL, GFP_ATOMIC); + genlmsg_multicast_allns(&genl_ctrl, msg, 0, + 0, GFP_ATOMIC); rcu_read_unlock(); } return 0; } -static struct genl_ops genl_ctrl_ops = { - .cmd = CTRL_CMD_GETFAMILY, - .doit = ctrl_getfamily, - .dumpit = ctrl_dumpfamily, - .policy = ctrl_policy, +static struct genl_ops genl_ctrl_ops[] = { + { + .cmd = CTRL_CMD_GETFAMILY, + .doit = ctrl_getfamily, + .dumpit = ctrl_dumpfamily, + .policy = ctrl_policy, + }, }; -static struct genl_multicast_group notify_grp = { - .name = "notify", +static struct genl_multicast_group genl_ctrl_groups[] = { + { .name = "notify", }, }; static int __net_init genl_pernet_init(struct net *net) @@ -954,7 +996,8 @@ static int __init genl_init(void) for (i = 0; i < GENL_FAM_TAB_SIZE; i++) INIT_LIST_HEAD(&family_ht[i]); - err = genl_register_family_with_ops(&genl_ctrl, &genl_ctrl_ops, 1); + err = genl_register_family_with_ops_groups(&genl_ctrl, genl_ctrl_ops, + genl_ctrl_groups); if (err < 0) goto problem; @@ -962,10 +1005,6 @@ static int __init genl_init(void) if (err) goto problem; - err = genl_register_mc_group(&genl_ctrl, ¬ify_grp); - if (err < 0) - goto problem; - return 0; problem: @@ -1003,14 +1042,18 @@ static int genlmsg_mcast(struct sk_buff *skb, u32 portid, unsigned long group, return err; } -int genlmsg_multicast_allns(struct sk_buff *skb, u32 portid, unsigned int group, - gfp_t flags) +int genlmsg_multicast_allns(struct genl_family *family, struct sk_buff *skb, + u32 portid, unsigned int group, gfp_t flags) { + if (group >= family->n_mcgrps) + return -EINVAL; + group = family->mcgrp_offset + group; return genlmsg_mcast(skb, portid, group, flags); } EXPORT_SYMBOL(genlmsg_multicast_allns); -void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group, +void genl_notify(struct genl_family *family, + struct sk_buff *skb, struct net *net, u32 portid, u32 group, struct nlmsghdr *nlh, gfp_t flags) { struct sock *sk = net->genl_sock; @@ -1019,6 +1062,9 @@ void genl_notify(struct sk_buff *skb, struct net *net, u32 portid, u32 group, if (nlh) report = nlmsg_report(nlh); + if (group >= family->n_mcgrps) + return; + group = family->mcgrp_offset + group; nlmsg_notify(sk, skb, portid, group, report, flags); } EXPORT_SYMBOL(genl_notify); |