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Release 4.17 lib/kobject_uevent.c

Directory: lib
// 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             <rml@novell.com>
 *      Kay Sievers             <kay.sievers@vrfy.org>
 *      Arjan van de Ven        <arjanv@redhat.com>
 *      Greg Kroah-Hartman      <greg@kroah.com>
 */

#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/kobject.h>
#include <linux/export.h>
#include <linux/kmod.h>
#include <linux/slab.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/netlink.h>
#include <linux/uuid.h>
#include <linux/ctype.h>
#include <net/sock.h>
#include <net/netlink.h>
#include <net/net_namespace.h>



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; }

Contributors

PersonTokensPropCommitsCommitProp
Kay Sievers11361.41%133.33%
Peter Rajnoha6032.61%133.33%
Mark Lord115.98%133.33%
Total184100.00%3100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Peter Rajnoha64100.00%1100.00%
Total64100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Peter Rajnoha303100.00%1100.00%
Total303100.00%1100.00%

/** * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Peter Rajnoha205100.00%1100.00%
Total205100.00%1100.00%

#ifdef CONFIG_NET
static int kobj_bcast_filter(struct sock *dsk, struct sk_buff *skb, void *data) { struct kobject *kobj = data, *ksobj; const struct kobj_ns_type_operations *ops; ops = kobj_ns_ops(kobj); if (!ops && kobj->kset) { ksobj = &kobj->kset->kobj; if (ksobj->parent != NULL) ops = kobj_ns_ops(ksobj->parent); } if (ops && ops->netlink_ns && kobj->ktype->namespace) { const void *sock_ns, *ns; ns = kobj->ktype->namespace(kobj); sock_ns = ops->netlink_ns(dsk); return sock_ns != ns; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann8262.12%150.00%
Weilong Chen5037.88%150.00%
Total132100.00%2100.00%

#endif #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; }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann64100.00%1100.00%
Total64100.00%1100.00%


static int init_uevent_argv(struct kobj_uevent_env *env, const char *subsystem) { int len; len = strlcpy(&env->buf[env->buflen], subsystem, sizeof(env->buf) - env->buflen); if (len >= (sizeof(env->buf) - env->buflen)) { WARN(1, KERN_ERR "init_uevent_argv: buffer size too small\n"); return -ENOMEM; } env->argv[0] = uevent_helper; env->argv[1] = &env->buf[env->buflen]; env->argv[2] = NULL; env->buflen += len + 1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Vladimir Davydov124100.00%1100.00%
Total124100.00%1100.00%


static void cleanup_uevent_env(struct subprocess_info *info) { kfree(info->data); }

Contributors

PersonTokensPropCommitsCommitProp
Vladimir Davydov18100.00%1100.00%
Total18100.00%1100.00%

#endif
static int kobject_uevent_net_broadcast(struct kobject *kobj, struct kobj_uevent_env *env, const char *action_string, const char *devpath) { int retval = 0; #if defined(CONFIG_NET) struct sk_buff *skb = NULL; struct uevent_sock *ue_sk; /* 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) { /* allocate message with the maximum possible size */ size_t len = strlen(action_string) + strlen(devpath) + 2; char *scratch; retval = -ENOMEM; skb = alloc_skb(len + env->buflen, GFP_KERNEL); if (!skb) continue; /* add header */ scratch = skb_put(skb, len); sprintf(scratch, "%s@%s", action_string, devpath); skb_put_data(skb, env->buf, env->buflen); NETLINK_CB(skb).dst_group = 1; } retval = netlink_broadcast_filtered(uevent_sock, skb_get(skb), 0, 1, GFP_KERNEL, kobj_bcast_filter, kobj); /* ENOBUFS should be handled in userspace */ if (retval == -ENOBUFS || retval == -ESRCH) retval = 0; } consume_skb(skb); #endif return retval; }

Contributors

PersonTokensPropCommitsCommitProp
Eric Dumazet223100.00%3100.00%
Total223100.00%3100.00%


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; } }

Contributors

PersonTokensPropCommitsCommitProp
Dmitry Torokhov166100.00%2100.00%
Total166100.00%2100.00%

/** * 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; 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_REMOVE: kobj->state_remove_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; }

Contributors

PersonTokensPropCommitsCommitProp
Greg Kroah-Hartman24734.94%414.29%
Kay Sievers24334.37%725.00%
Vladimir Davydov567.92%13.57%
Aneesh Kumar K.V365.09%13.57%
Lei Ming273.82%13.57%
Dmitry Torokhov233.25%27.14%
Cornelia Huck202.83%13.57%
Andrey Vagin131.84%13.57%
Eric W. Biedermann121.70%27.14%
Andrew Morton101.41%13.57%
Harvey Harrison50.71%13.57%
Michael Marineau50.71%13.57%
Eric Dumazet40.57%13.57%
Tejun Heo20.28%13.57%
Wang Chen20.28%13.57%
John Anthony Kazos Jr10.14%13.57%
Emese Revfy10.14%13.57%
Total707100.00%28100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Cornelia Huck2187.50%150.00%
Aneesh Kumar K.V312.50%150.00%
Total24100.00%2100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Kay Sievers8756.49%250.00%
Roland Dreier6139.61%125.00%
Arjan van de Ven63.90%125.00%
Total154100.00%4100.00%

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; }

Contributors

PersonTokensPropCommitsCommitProp
Christian Brauner203100.00%1100.00%
Total203100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Christian Brauner111100.00%1100.00%
Total111100.00%1100.00%


static void uevent_net_rcv(struct sk_buff *skb) { netlink_rcv_skb(skb, &uevent_net_rcv_skb); }

Contributors

PersonTokensPropCommitsCommitProp
Christian Brauner19100.00%1100.00%
Total19100.00%1100.00%


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; mutex_lock(&uevent_sock_mutex); list_add_tail(&ue_sk->list, &uevent_sock_list); mutex_unlock(&uevent_sock_mutex); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann6651.16%225.00%
Kay Sievers2922.48%112.50%
Pablo Neira Ayuso1713.18%225.00%
Christian Brauner129.30%225.00%
Dan Carpenter53.88%112.50%
Total129100.00%8100.00%


static void uevent_net_exit(struct net *net) { struct uevent_sock *ue_sk = net->uevent_sock; mutex_lock(&uevent_sock_mutex); list_del(&ue_sk->list); mutex_unlock(&uevent_sock_mutex); netlink_kernel_release(ue_sk->sk); kfree(ue_sk); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann4892.31%150.00%
Christian Brauner47.69%150.00%
Total52100.00%2100.00%

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); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann1381.25%150.00%
Kay Sievers318.75%150.00%
Total16100.00%2100.00%

postcore_initcall(kobject_uevent_init); #endif

Overall Contributors

PersonTokensPropCommitsCommitProp
Peter Rajnoha63920.57%11.82%
Kay Sievers53917.35%1018.18%
Christian Brauner35511.43%23.64%
Eric W. Biedermann32710.52%47.27%
Greg Kroah-Hartman2738.79%610.91%
Eric Dumazet2277.31%35.45%
Dmitry Torokhov2016.47%47.27%
Vladimir Davydov1986.37%11.82%
Roland Dreier642.06%11.82%
Weilong Chen501.61%11.82%
Cornelia Huck461.48%11.82%
Aneesh Kumar K.V391.26%11.82%
Lei Ming270.87%11.82%
Pablo Neira Ayuso170.55%23.64%
Andrey Vagin160.51%11.82%
Andrew Morton150.48%23.64%
Michael Marineau150.48%11.82%
Mark Lord110.35%11.82%
Jun'ichi Nomura100.32%11.82%
Denis V. Lunev70.23%11.82%
Arjan van de Ven60.19%11.82%
Dan Carpenter50.16%11.82%
Harvey Harrison50.16%11.82%
Tejun Heo50.16%23.64%
Paul Gortmaker40.13%11.82%
Wang Chen20.06%11.82%
Julia Lawall20.06%11.82%
John Anthony Kazos Jr10.03%11.82%
Emese Revfy10.03%11.82%
Total3107100.00%55100.00%
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