diff options
| -rw-r--r-- | fs/proc/Kconfig | 7 | ||||
| -rw-r--r-- | fs/proc/Makefile | 1 | ||||
| -rw-r--r-- | fs/proc/internal.h | 9 | ||||
| -rw-r--r-- | fs/proc/root.c | 2 | ||||
| -rw-r--r-- | fs/proc/uid.c | 278 | ||||
| -rw-r--r-- | include/linux/proc_fs.h | 6 | ||||
| -rw-r--r-- | kernel/user.c | 3 |
7 files changed, 305 insertions, 1 deletions
diff --git a/fs/proc/Kconfig b/fs/proc/Kconfig index 1ade1206bb89..523bfc094e42 100644 --- a/fs/proc/Kconfig +++ b/fs/proc/Kconfig @@ -81,3 +81,10 @@ config PROC_CHILDREN Say Y if you are running any user-space software which takes benefit from this interface. For example, rkt is such a piece of software. + +config PROC_UID + bool "Include /proc/uid/ files" + default y + depends on PROC_FS + help + Provides aggregated per-uid information under /proc/uid. diff --git a/fs/proc/Makefile b/fs/proc/Makefile index 7151ea428041..baab1daf7585 100644 --- a/fs/proc/Makefile +++ b/fs/proc/Makefile @@ -24,6 +24,7 @@ proc-y += softirqs.o proc-y += namespaces.o proc-y += self.o proc-y += thread_self.o +proc-$(CONFIG_PROC_UID) += uid.o proc-$(CONFIG_PROC_SYSCTL) += proc_sysctl.o proc-$(CONFIG_NET) += proc_net.o proc-$(CONFIG_PROC_KCORE) += kcore.o diff --git a/fs/proc/internal.h b/fs/proc/internal.h index aa2781095bd1..fa4dd182bfaa 100644 --- a/fs/proc/internal.h +++ b/fs/proc/internal.h @@ -256,6 +256,15 @@ static inline void sysctl_head_put(struct ctl_table_header *head) { } #endif /* + * uid.c + */ +#ifdef CONFIG_PROC_UID +extern int proc_uid_init(void); +#else +static inline void proc_uid_init(void) { } +#endif + +/* * proc_tty.c */ #ifdef CONFIG_TTY diff --git a/fs/proc/root.c b/fs/proc/root.c index ec649c92d270..1d0b6a125563 100644 --- a/fs/proc/root.c +++ b/fs/proc/root.c @@ -182,7 +182,7 @@ void __init proc_root_init(void) proc_symlink("mounts", NULL, "self/mounts"); proc_net_init(); - + proc_uid_init(); #ifdef CONFIG_SYSVIPC proc_mkdir("sysvipc", NULL); #endif diff --git a/fs/proc/uid.c b/fs/proc/uid.c new file mode 100644 index 000000000000..3c7e87c2a820 --- /dev/null +++ b/fs/proc/uid.c @@ -0,0 +1,278 @@ +/* + * /proc/uid support + */ + +#include <linux/fs.h> +#include <linux/hashtable.h> +#include <linux/init.h> +#include <linux/proc_fs.h> +#include <linux/sched.h> +#include <linux/seq_file.h> +#include <linux/slab.h> +#include "internal.h" + +struct proc_dir_entry *proc_uid; + +#define UID_HASH_BITS 10 + +static DECLARE_HASHTABLE(proc_uid_hash_table, UID_HASH_BITS); + +/* + * use rt_mutex here to avoid priority inversion between high-priority readers + * of these files and tasks calling proc_register_uid(). + */ +static DEFINE_RT_MUTEX(proc_uid_lock); /* proc_uid_hash_table */ + +struct uid_hash_entry { + uid_t uid; + struct hlist_node hash; +}; + +/* Caller must hold proc_uid_lock */ +static bool uid_hash_entry_exists_locked(uid_t uid) +{ + struct uid_hash_entry *entry; + + hash_for_each_possible(proc_uid_hash_table, entry, hash, uid) { + if (entry->uid == uid) + return true; + } + return false; +} + +void proc_register_uid(kuid_t kuid) +{ + struct uid_hash_entry *entry; + bool exists; + uid_t uid = from_kuid_munged(current_user_ns(), kuid); + + rt_mutex_lock(&proc_uid_lock); + exists = uid_hash_entry_exists_locked(uid); + rt_mutex_unlock(&proc_uid_lock); + if (exists) + return; + + entry = kzalloc(sizeof(struct uid_hash_entry), GFP_KERNEL); + if (!entry) + return; + entry->uid = uid; + + rt_mutex_lock(&proc_uid_lock); + if (uid_hash_entry_exists_locked(uid)) + kfree(entry); + else + hash_add(proc_uid_hash_table, &entry->hash, uid); + rt_mutex_unlock(&proc_uid_lock); +} + +struct uid_entry { + const char *name; + int len; + umode_t mode; + const struct inode_operations *iop; + const struct file_operations *fop; +}; + +#define NOD(NAME, MODE, IOP, FOP) { \ + .name = (NAME), \ + .len = sizeof(NAME) - 1, \ + .mode = MODE, \ + .iop = IOP, \ + .fop = FOP, \ +} + +static const struct uid_entry uid_base_stuff[] = {}; + +const struct inode_operations proc_uid_def_inode_operations = { + .setattr = proc_setattr, +}; + +struct inode *proc_uid_make_inode(struct super_block *sb, kuid_t kuid) +{ + struct inode *inode; + + inode = new_inode(sb); + if (!inode) + return NULL; + + inode->i_ino = get_next_ino(); + inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME; + inode->i_op = &proc_uid_def_inode_operations; + inode->i_uid = kuid; + + return inode; +} + +static int proc_uident_instantiate(struct inode *dir, struct dentry *dentry, + struct task_struct *unused, const void *ptr) +{ + const struct uid_entry *u = ptr; + struct inode *inode; + + inode = proc_uid_make_inode(dir->i_sb, dir->i_uid); + if (!inode) + return -ENOENT; + + inode->i_mode = u->mode; + if (S_ISDIR(inode->i_mode)) + set_nlink(inode, 2); + if (u->iop) + inode->i_op = u->iop; + if (u->fop) + inode->i_fop = u->fop; + d_add(dentry, inode); + return 0; +} + +static struct dentry *proc_uid_base_lookup(struct inode *dir, + struct dentry *dentry, + unsigned int flags) +{ + const struct uid_entry *u, *last; + unsigned int nents = ARRAY_SIZE(uid_base_stuff); + + if (nents == 0) + return ERR_PTR(-ENOENT); + + last = &uid_base_stuff[nents - 1]; + for (u = uid_base_stuff; u <= last; u++) { + if (u->len != dentry->d_name.len) + continue; + if (!memcmp(dentry->d_name.name, u->name, u->len)) + break; + } + if (u > last) + return ERR_PTR(-ENOENT); + + return ERR_PTR(proc_uident_instantiate(dir, dentry, NULL, u)); +} + +static int proc_uid_base_readdir(struct file *file, struct dir_context *ctx) +{ + unsigned int nents = ARRAY_SIZE(uid_base_stuff); + const struct uid_entry *u; + + if (!dir_emit_dots(file, ctx)) + return 0; + + if (ctx->pos >= nents + 2) + return 0; + + for (u = uid_base_stuff + (ctx->pos - 2); + u <= uid_base_stuff + nents - 1; u++) { + if (!proc_fill_cache(file, ctx, u->name, u->len, + proc_uident_instantiate, NULL, u)) + break; + ctx->pos++; + } + + return 0; +} + +static const struct inode_operations proc_uid_base_inode_operations = { + .lookup = proc_uid_base_lookup, + .setattr = proc_setattr, +}; + +static const struct file_operations proc_uid_base_operations = { + .read = generic_read_dir, + .iterate = proc_uid_base_readdir, + .llseek = default_llseek, +}; + +static int proc_uid_instantiate(struct inode *dir, struct dentry *dentry, + struct task_struct *unused, const void *ptr) +{ + unsigned int i, len; + nlink_t nlinks; + kuid_t *kuid = (kuid_t *)ptr; + struct inode *inode = proc_uid_make_inode(dir->i_sb, *kuid); + + if (!inode) + return -ENOENT; + + inode->i_mode = S_IFDIR | 0555; + inode->i_op = &proc_uid_base_inode_operations; + inode->i_fop = &proc_uid_base_operations; + inode->i_flags |= S_IMMUTABLE; + + nlinks = 2; + len = ARRAY_SIZE(uid_base_stuff); + for (i = 0; i < len; ++i) { + if (S_ISDIR(uid_base_stuff[i].mode)) + ++nlinks; + } + set_nlink(inode, nlinks); + + d_add(dentry, inode); + + return 0; +} + +static int proc_uid_readdir(struct file *file, struct dir_context *ctx) +{ + int last_shown, i; + unsigned long bkt; + struct uid_hash_entry *entry; + + if (!dir_emit_dots(file, ctx)) + return 0; + + i = 0; + last_shown = ctx->pos - 2; + rt_mutex_lock(&proc_uid_lock); + hash_for_each(proc_uid_hash_table, bkt, entry, hash) { + int len; + char buf[PROC_NUMBUF]; + + if (i < last_shown) + continue; + len = snprintf(buf, sizeof(buf), "%u", entry->uid); + if (!proc_fill_cache(file, ctx, buf, len, + proc_uid_instantiate, NULL, &entry->uid)) + break; + i++; + ctx->pos++; + } + rt_mutex_unlock(&proc_uid_lock); + return 0; +} + +static struct dentry *proc_uid_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags) +{ + int result = -ENOENT; + + uid_t uid = name_to_int(&dentry->d_name); + bool uid_exists; + + rt_mutex_lock(&proc_uid_lock); + uid_exists = uid_hash_entry_exists_locked(uid); + rt_mutex_unlock(&proc_uid_lock); + if (uid_exists) { + kuid_t kuid = make_kuid(current_user_ns(), uid); + + result = proc_uid_instantiate(dir, dentry, NULL, &kuid); + } + return ERR_PTR(result); +} + +static const struct file_operations proc_uid_operations = { + .read = generic_read_dir, + .iterate = proc_uid_readdir, + .llseek = default_llseek, +}; + +static const struct inode_operations proc_uid_inode_operations = { + .lookup = proc_uid_lookup, + .setattr = proc_setattr, +}; + +int __init proc_uid_init(void) +{ + proc_uid = proc_mkdir("uid", NULL); + proc_uid->proc_iops = &proc_uid_inode_operations; + proc_uid->proc_fops = &proc_uid_operations; + + return 0; +} diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h index b97bf2ef996e..b326d0a0cace 100644 --- a/include/linux/proc_fs.h +++ b/include/linux/proc_fs.h @@ -74,6 +74,12 @@ static inline int remove_proc_subtree(const char *name, struct proc_dir_entry *p #endif /* CONFIG_PROC_FS */ +#ifdef CONFIG_PROC_UID +extern void proc_register_uid(kuid_t uid); +#else +static inline void proc_register_uid(kuid_t uid) {} +#endif + struct net; static inline struct proc_dir_entry *proc_net_mkdir( diff --git a/kernel/user.c b/kernel/user.c index b069ccbfb0b0..41e94e453836 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -16,6 +16,7 @@ #include <linux/interrupt.h> #include <linux/export.h> #include <linux/user_namespace.h> +#include <linux/proc_fs.h> #include <linux/proc_ns.h> /* @@ -201,6 +202,7 @@ struct user_struct *alloc_uid(kuid_t uid) } spin_unlock_irq(&uidhash_lock); } + proc_register_uid(uid); return up; @@ -222,6 +224,7 @@ static int __init uid_cache_init(void) spin_lock_irq(&uidhash_lock); uid_hash_insert(&root_user, uidhashentry(GLOBAL_ROOT_UID)); spin_unlock_irq(&uidhash_lock); + proc_register_uid(GLOBAL_ROOT_UID); return 0; } |