From 76cb841cb886eef6b3bee341a2266c76578724ad Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:02:30 +0200 Subject: Adding upstream version 4.19.249. Signed-off-by: Daniel Baumann --- lib/kobject_uevent.c | 814 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 814 insertions(+) create mode 100644 lib/kobject_uevent.c (limited to 'lib/kobject_uevent.c') diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c new file mode 100644 index 000000000..26d21339b --- /dev/null +++ b/lib/kobject_uevent.c @@ -0,0 +1,814 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * kernel userspace event delivery + * + * Copyright (C) 2004 Red Hat, Inc. All rights reserved. + * Copyright (C) 2004 Novell, Inc. All rights reserved. + * Copyright (C) 2004 IBM, Inc. All rights reserved. + * + * Authors: + * Robert Love + * Kay Sievers + * Arjan van de Ven + * Greg Kroah-Hartman + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + + +u64 uevent_seqnum; +#ifdef CONFIG_UEVENT_HELPER +char uevent_helper[UEVENT_HELPER_PATH_LEN] = CONFIG_UEVENT_HELPER_PATH; +#endif + +struct uevent_sock { + struct list_head list; + struct sock *sk; +}; + +#ifdef CONFIG_NET +static LIST_HEAD(uevent_sock_list); +#endif + +/* This lock protects uevent_seqnum and uevent_sock_list */ +static DEFINE_MUTEX(uevent_sock_mutex); + +/* the strings here must match the enum in include/linux/kobject.h */ +static const char *kobject_actions[] = { + [KOBJ_ADD] = "add", + [KOBJ_REMOVE] = "remove", + [KOBJ_CHANGE] = "change", + [KOBJ_MOVE] = "move", + [KOBJ_ONLINE] = "online", + [KOBJ_OFFLINE] = "offline", + [KOBJ_BIND] = "bind", + [KOBJ_UNBIND] = "unbind", +}; + +static int kobject_action_type(const char *buf, size_t count, + enum kobject_action *type, + const char **args) +{ + enum kobject_action action; + size_t count_first; + const char *args_start; + int ret = -EINVAL; + + if (count && (buf[count-1] == '\n' || buf[count-1] == '\0')) + count--; + + if (!count) + goto out; + + args_start = strnchr(buf, count, ' '); + if (args_start) { + count_first = args_start - buf; + args_start = args_start + 1; + } else + count_first = count; + + for (action = 0; action < ARRAY_SIZE(kobject_actions); action++) { + if (strncmp(kobject_actions[action], buf, count_first) != 0) + continue; + if (kobject_actions[action][count_first] != '\0') + continue; + if (args) + *args = args_start; + *type = action; + ret = 0; + break; + } +out: + return ret; +} + +static const char *action_arg_word_end(const char *buf, const char *buf_end, + char delim) +{ + const char *next = buf; + + while (next <= buf_end && *next != delim) + if (!isalnum(*next++)) + return NULL; + + if (next == buf) + return NULL; + + return next; +} + +static int kobject_action_args(const char *buf, size_t count, + struct kobj_uevent_env **ret_env) +{ + struct kobj_uevent_env *env = NULL; + const char *next, *buf_end, *key; + int key_len; + int r = -EINVAL; + + if (count && (buf[count - 1] == '\n' || buf[count - 1] == '\0')) + count--; + + if (!count) + return -EINVAL; + + env = kzalloc(sizeof(*env), GFP_KERNEL); + if (!env) + return -ENOMEM; + + /* first arg is UUID */ + if (count < UUID_STRING_LEN || !uuid_is_valid(buf) || + add_uevent_var(env, "SYNTH_UUID=%.*s", UUID_STRING_LEN, buf)) + goto out; + + /* + * the rest are custom environment variables in KEY=VALUE + * format with ' ' delimiter between each KEY=VALUE pair + */ + next = buf + UUID_STRING_LEN; + buf_end = buf + count - 1; + + while (next <= buf_end) { + if (*next != ' ') + goto out; + + /* skip the ' ', key must follow */ + key = ++next; + if (key > buf_end) + goto out; + + buf = next; + next = action_arg_word_end(buf, buf_end, '='); + if (!next || next > buf_end || *next != '=') + goto out; + key_len = next - buf; + + /* skip the '=', value must follow */ + if (++next > buf_end) + goto out; + + buf = next; + next = action_arg_word_end(buf, buf_end, ' '); + if (!next) + goto out; + + if (add_uevent_var(env, "SYNTH_ARG_%.*s=%.*s", + key_len, key, (int) (next - buf), buf)) + goto out; + } + + r = 0; +out: + if (r) + kfree(env); + else + *ret_env = env; + return r; +} + +/** + * kobject_synth_uevent - send synthetic uevent with arguments + * + * @kobj: struct kobject for which synthetic uevent is to be generated + * @buf: buffer containing action type and action args, newline is ignored + * @count: length of buffer + * + * Returns 0 if kobject_synthetic_uevent() is completed with success or the + * corresponding error when it fails. + */ +int kobject_synth_uevent(struct kobject *kobj, const char *buf, size_t count) +{ + char *no_uuid_envp[] = { "SYNTH_UUID=0", NULL }; + enum kobject_action action; + const char *action_args; + struct kobj_uevent_env *env; + const char *msg = NULL, *devpath; + int r; + + r = kobject_action_type(buf, count, &action, &action_args); + if (r) { + msg = "unknown uevent action string\n"; + goto out; + } + + if (!action_args) { + r = kobject_uevent_env(kobj, action, no_uuid_envp); + goto out; + } + + r = kobject_action_args(action_args, + count - (action_args - buf), &env); + if (r == -EINVAL) { + msg = "incorrect uevent action arguments\n"; + goto out; + } + + if (r) + goto out; + + r = kobject_uevent_env(kobj, action, env->envp); + kfree(env); +out: + if (r) { + devpath = kobject_get_path(kobj, GFP_KERNEL); + printk(KERN_WARNING "synth uevent: %s: %s", + devpath ?: "unknown device", + msg ?: "failed to send uevent"); + kfree(devpath); + } + return r; +} + +#ifdef CONFIG_UEVENT_HELPER +static int kobj_usermode_filter(struct kobject *kobj) +{ + const struct kobj_ns_type_operations *ops; + + ops = kobj_ns_ops(kobj); + if (ops) { + const void *init_ns, *ns; + ns = kobj->ktype->namespace(kobj); + init_ns = ops->initial_ns(); + return ns != init_ns; + } + + return 0; +} + +static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) +{ + int buffer_size = sizeof(env->buf) - env->buflen; + int len; + + len = strlcpy(&env->buf[env->buflen], subsystem, buffer_size); + if (len >= buffer_size) { + pr_warn("init_uevent_argv: buffer size of %d too small, needed %d\n", + buffer_size, len); + return -ENOMEM; + } + + env->argv[0] = uevent_helper; + env->argv[1] = &env->buf[env->buflen]; + env->argv[2] = NULL; + + env->buflen += len + 1; + return 0; +} + +static void cleanup_uevent_env(struct subprocess_info *info) +{ + kfree(info->data); +} +#endif + +#ifdef CONFIG_NET +static struct sk_buff *alloc_uevent_skb(struct kobj_uevent_env *env, + const char *action_string, + const char *devpath) +{ + struct netlink_skb_parms *parms; + struct sk_buff *skb = NULL; + char *scratch; + size_t len; + + /* allocate message with maximum possible size */ + len = strlen(action_string) + strlen(devpath) + 2; + skb = alloc_skb(len + env->buflen, GFP_KERNEL); + if (!skb) + return NULL; + + /* add header */ + scratch = skb_put(skb, len); + sprintf(scratch, "%s@%s", action_string, devpath); + + skb_put_data(skb, env->buf, env->buflen); + + parms = &NETLINK_CB(skb); + parms->creds.uid = GLOBAL_ROOT_UID; + parms->creds.gid = GLOBAL_ROOT_GID; + parms->dst_group = 1; + parms->portid = 0; + + return skb; +} + +static int uevent_net_broadcast_untagged(struct kobj_uevent_env *env, + const char *action_string, + const char *devpath) +{ + struct sk_buff *skb = NULL; + struct uevent_sock *ue_sk; + int retval = 0; + + /* send netlink message */ + list_for_each_entry(ue_sk, &uevent_sock_list, list) { + struct sock *uevent_sock = ue_sk->sk; + + if (!netlink_has_listeners(uevent_sock, 1)) + continue; + + if (!skb) { + retval = -ENOMEM; + skb = alloc_uevent_skb(env, action_string, devpath); + if (!skb) + continue; + } + + retval = netlink_broadcast(uevent_sock, skb_get(skb), 0, 1, + GFP_KERNEL); + /* ENOBUFS should be handled in userspace */ + if (retval == -ENOBUFS || retval == -ESRCH) + retval = 0; + } + consume_skb(skb); + + return retval; +} + +static int uevent_net_broadcast_tagged(struct sock *usk, + struct kobj_uevent_env *env, + const char *action_string, + const char *devpath) +{ + struct user_namespace *owning_user_ns = sock_net(usk)->user_ns; + struct sk_buff *skb = NULL; + int ret = 0; + + skb = alloc_uevent_skb(env, action_string, devpath); + if (!skb) + return -ENOMEM; + + /* fix credentials */ + if (owning_user_ns != &init_user_ns) { + struct netlink_skb_parms *parms = &NETLINK_CB(skb); + kuid_t root_uid; + kgid_t root_gid; + + /* fix uid */ + root_uid = make_kuid(owning_user_ns, 0); + if (uid_valid(root_uid)) + parms->creds.uid = root_uid; + + /* fix gid */ + root_gid = make_kgid(owning_user_ns, 0); + if (gid_valid(root_gid)) + parms->creds.gid = root_gid; + } + + ret = netlink_broadcast(usk, skb, 0, 1, GFP_KERNEL); + /* ENOBUFS should be handled in userspace */ + if (ret == -ENOBUFS || ret == -ESRCH) + ret = 0; + + return ret; +} +#endif + +static int kobject_uevent_net_broadcast(struct kobject *kobj, + struct kobj_uevent_env *env, + const char *action_string, + const char *devpath) +{ + int ret = 0; + +#ifdef CONFIG_NET + const struct kobj_ns_type_operations *ops; + const struct net *net = NULL; + + ops = kobj_ns_ops(kobj); + if (!ops && kobj->kset) { + struct kobject *ksobj = &kobj->kset->kobj; + if (ksobj->parent != NULL) + ops = kobj_ns_ops(ksobj->parent); + } + + /* kobjects currently only carry network namespace tags and they + * are the only tag relevant here since we want to decide which + * network namespaces to broadcast the uevent into. + */ + if (ops && ops->netlink_ns && kobj->ktype->namespace) + if (ops->type == KOBJ_NS_TYPE_NET) + net = kobj->ktype->namespace(kobj); + + if (!net) + ret = uevent_net_broadcast_untagged(env, action_string, + devpath); + else + ret = uevent_net_broadcast_tagged(net->uevent_sock->sk, env, + action_string, devpath); +#endif + + return ret; +} + +static void zap_modalias_env(struct kobj_uevent_env *env) +{ + static const char modalias_prefix[] = "MODALIAS="; + size_t len; + int i, j; + + for (i = 0; i < env->envp_idx;) { + if (strncmp(env->envp[i], modalias_prefix, + sizeof(modalias_prefix) - 1)) { + i++; + continue; + } + + len = strlen(env->envp[i]) + 1; + + if (i != env->envp_idx - 1) { + memmove(env->envp[i], env->envp[i + 1], + env->buflen - len); + + for (j = i; j < env->envp_idx - 1; j++) + env->envp[j] = env->envp[j + 1] - len; + } + + env->envp_idx--; + env->buflen -= len; + } +} + +/** + * kobject_uevent_env - send an uevent with environmental data + * + * @kobj: struct kobject that the action is happening to + * @action: action that is happening + * @envp_ext: pointer to environmental data + * + * Returns 0 if kobject_uevent_env() is completed with success or the + * corresponding error when it fails. + */ +int kobject_uevent_env(struct kobject *kobj, enum kobject_action action, + char *envp_ext[]) +{ + struct kobj_uevent_env *env; + const char *action_string = kobject_actions[action]; + const char *devpath = NULL; + const char *subsystem; + struct kobject *top_kobj; + struct kset *kset; + const struct kset_uevent_ops *uevent_ops; + int i = 0; + int retval = 0; + + /* + * Mark "remove" event done regardless of result, for some subsystems + * do not want to re-trigger "remove" event via automatic cleanup. + */ + if (action == KOBJ_REMOVE) + kobj->state_remove_uevent_sent = 1; + + pr_debug("kobject: '%s' (%p): %s\n", + kobject_name(kobj), kobj, __func__); + + /* search the kset we belong to */ + top_kobj = kobj; + while (!top_kobj->kset && top_kobj->parent) + top_kobj = top_kobj->parent; + + if (!top_kobj->kset) { + pr_debug("kobject: '%s' (%p): %s: attempted to send uevent " + "without kset!\n", kobject_name(kobj), kobj, + __func__); + return -EINVAL; + } + + kset = top_kobj->kset; + uevent_ops = kset->uevent_ops; + + /* skip the event, if uevent_suppress is set*/ + if (kobj->uevent_suppress) { + pr_debug("kobject: '%s' (%p): %s: uevent_suppress " + "caused the event to drop!\n", + kobject_name(kobj), kobj, __func__); + return 0; + } + /* skip the event, if the filter returns zero. */ + if (uevent_ops && uevent_ops->filter) + if (!uevent_ops->filter(kset, kobj)) { + pr_debug("kobject: '%s' (%p): %s: filter function " + "caused the event to drop!\n", + kobject_name(kobj), kobj, __func__); + return 0; + } + + /* originating subsystem */ + if (uevent_ops && uevent_ops->name) + subsystem = uevent_ops->name(kset, kobj); + else + subsystem = kobject_name(&kset->kobj); + if (!subsystem) { + pr_debug("kobject: '%s' (%p): %s: unset subsystem caused the " + "event to drop!\n", kobject_name(kobj), kobj, + __func__); + return 0; + } + + /* environment buffer */ + env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL); + if (!env) + return -ENOMEM; + + /* complete object path */ + devpath = kobject_get_path(kobj, GFP_KERNEL); + if (!devpath) { + retval = -ENOENT; + goto exit; + } + + /* default keys */ + retval = add_uevent_var(env, "ACTION=%s", action_string); + if (retval) + goto exit; + retval = add_uevent_var(env, "DEVPATH=%s", devpath); + if (retval) + goto exit; + retval = add_uevent_var(env, "SUBSYSTEM=%s", subsystem); + if (retval) + goto exit; + + /* keys passed in from the caller */ + if (envp_ext) { + for (i = 0; envp_ext[i]; i++) { + retval = add_uevent_var(env, "%s", envp_ext[i]); + if (retval) + goto exit; + } + } + + /* let the kset specific function add its stuff */ + if (uevent_ops && uevent_ops->uevent) { + retval = uevent_ops->uevent(kset, kobj, env); + if (retval) { + pr_debug("kobject: '%s' (%p): %s: uevent() returned " + "%d\n", kobject_name(kobj), kobj, + __func__, retval); + goto exit; + } + } + + switch (action) { + case KOBJ_ADD: + /* + * Mark "add" event so we can make sure we deliver "remove" + * event to userspace during automatic cleanup. If + * the object did send an "add" event, "remove" will + * automatically generated by the core, if not already done + * by the caller. + */ + kobj->state_add_uevent_sent = 1; + break; + + case KOBJ_UNBIND: + zap_modalias_env(env); + break; + + default: + break; + } + + mutex_lock(&uevent_sock_mutex); + /* we will send an event, so request a new sequence number */ + retval = add_uevent_var(env, "SEQNUM=%llu", (unsigned long long)++uevent_seqnum); + if (retval) { + mutex_unlock(&uevent_sock_mutex); + goto exit; + } + retval = kobject_uevent_net_broadcast(kobj, env, action_string, + devpath); + mutex_unlock(&uevent_sock_mutex); + +#ifdef CONFIG_UEVENT_HELPER + /* call uevent_helper, usually only enabled during early boot */ + if (uevent_helper[0] && !kobj_usermode_filter(kobj)) { + struct subprocess_info *info; + + retval = add_uevent_var(env, "HOME=/"); + if (retval) + goto exit; + retval = add_uevent_var(env, + "PATH=/sbin:/bin:/usr/sbin:/usr/bin"); + if (retval) + goto exit; + retval = init_uevent_argv(env, subsystem); + if (retval) + goto exit; + + retval = -ENOMEM; + info = call_usermodehelper_setup(env->argv[0], env->argv, + env->envp, GFP_KERNEL, + NULL, cleanup_uevent_env, env); + if (info) { + retval = call_usermodehelper_exec(info, UMH_NO_WAIT); + env = NULL; /* freed by cleanup_uevent_env */ + } + } +#endif + +exit: + kfree(devpath); + kfree(env); + return retval; +} +EXPORT_SYMBOL_GPL(kobject_uevent_env); + +/** + * kobject_uevent - notify userspace by sending an uevent + * + * @kobj: struct kobject that the action is happening to + * @action: action that is happening + * + * Returns 0 if kobject_uevent() is completed with success or the + * corresponding error when it fails. + */ +int kobject_uevent(struct kobject *kobj, enum kobject_action action) +{ + return kobject_uevent_env(kobj, action, NULL); +} +EXPORT_SYMBOL_GPL(kobject_uevent); + +/** + * add_uevent_var - add key value string to the environment buffer + * @env: environment buffer structure + * @format: printf format for the key=value pair + * + * Returns 0 if environment variable was added successfully or -ENOMEM + * if no space was available. + */ +int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...) +{ + va_list args; + int len; + + if (env->envp_idx >= ARRAY_SIZE(env->envp)) { + WARN(1, KERN_ERR "add_uevent_var: too many keys\n"); + return -ENOMEM; + } + + va_start(args, format); + len = vsnprintf(&env->buf[env->buflen], + sizeof(env->buf) - env->buflen, + format, args); + va_end(args); + + if (len >= (sizeof(env->buf) - env->buflen)) { + WARN(1, KERN_ERR "add_uevent_var: buffer size too small\n"); + return -ENOMEM; + } + + env->envp[env->envp_idx++] = &env->buf[env->buflen]; + env->buflen += len + 1; + return 0; +} +EXPORT_SYMBOL_GPL(add_uevent_var); + +#if defined(CONFIG_NET) +static int uevent_net_broadcast(struct sock *usk, struct sk_buff *skb, + struct netlink_ext_ack *extack) +{ + /* u64 to chars: 2^64 - 1 = 21 chars */ + char buf[sizeof("SEQNUM=") + 21]; + struct sk_buff *skbc; + int ret; + + /* bump and prepare sequence number */ + ret = snprintf(buf, sizeof(buf), "SEQNUM=%llu", ++uevent_seqnum); + if (ret < 0 || (size_t)ret >= sizeof(buf)) + return -ENOMEM; + ret++; + + /* verify message does not overflow */ + if ((skb->len + ret) > UEVENT_BUFFER_SIZE) { + NL_SET_ERR_MSG(extack, "uevent message too big"); + return -EINVAL; + } + + /* copy skb and extend to accommodate sequence number */ + skbc = skb_copy_expand(skb, 0, ret, GFP_KERNEL); + if (!skbc) + return -ENOMEM; + + /* append sequence number */ + skb_put_data(skbc, buf, ret); + + /* remove msg header */ + skb_pull(skbc, NLMSG_HDRLEN); + + /* set portid 0 to inform userspace message comes from kernel */ + NETLINK_CB(skbc).portid = 0; + NETLINK_CB(skbc).dst_group = 1; + + ret = netlink_broadcast(usk, skbc, 0, 1, GFP_KERNEL); + /* ENOBUFS should be handled in userspace */ + if (ret == -ENOBUFS || ret == -ESRCH) + ret = 0; + + return ret; +} + +static int uevent_net_rcv_skb(struct sk_buff *skb, struct nlmsghdr *nlh, + struct netlink_ext_ack *extack) +{ + struct net *net; + int ret; + + if (!nlmsg_data(nlh)) + return -EINVAL; + + /* + * Verify that we are allowed to send messages to the target + * network namespace. The caller must have CAP_SYS_ADMIN in the + * owning user namespace of the target network namespace. + */ + net = sock_net(NETLINK_CB(skb).sk); + if (!netlink_ns_capable(skb, net->user_ns, CAP_SYS_ADMIN)) { + NL_SET_ERR_MSG(extack, "missing CAP_SYS_ADMIN capability"); + return -EPERM; + } + + mutex_lock(&uevent_sock_mutex); + ret = uevent_net_broadcast(net->uevent_sock->sk, skb, extack); + mutex_unlock(&uevent_sock_mutex); + + return ret; +} + +static void uevent_net_rcv(struct sk_buff *skb) +{ + netlink_rcv_skb(skb, &uevent_net_rcv_skb); +} + +static int uevent_net_init(struct net *net) +{ + struct uevent_sock *ue_sk; + struct netlink_kernel_cfg cfg = { + .groups = 1, + .input = uevent_net_rcv, + .flags = NL_CFG_F_NONROOT_RECV + }; + + ue_sk = kzalloc(sizeof(*ue_sk), GFP_KERNEL); + if (!ue_sk) + return -ENOMEM; + + ue_sk->sk = netlink_kernel_create(net, NETLINK_KOBJECT_UEVENT, &cfg); + if (!ue_sk->sk) { + printk(KERN_ERR + "kobject_uevent: unable to create netlink socket!\n"); + kfree(ue_sk); + return -ENODEV; + } + + net->uevent_sock = ue_sk; + + /* Restrict uevents to initial user namespace. */ + if (sock_net(ue_sk->sk)->user_ns == &init_user_ns) { + mutex_lock(&uevent_sock_mutex); + list_add_tail(&ue_sk->list, &uevent_sock_list); + mutex_unlock(&uevent_sock_mutex); + } + + return 0; +} + +static void uevent_net_exit(struct net *net) +{ + struct uevent_sock *ue_sk = net->uevent_sock; + + if (sock_net(ue_sk->sk)->user_ns == &init_user_ns) { + mutex_lock(&uevent_sock_mutex); + list_del(&ue_sk->list); + mutex_unlock(&uevent_sock_mutex); + } + + netlink_kernel_release(ue_sk->sk); + kfree(ue_sk); +} + +static struct pernet_operations uevent_net_ops = { + .init = uevent_net_init, + .exit = uevent_net_exit, +}; + +static int __init kobject_uevent_init(void) +{ + return register_pernet_subsys(&uevent_net_ops); +} + + +postcore_initcall(kobject_uevent_init); +#endif -- cgit v1.2.3