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authorLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 17:42:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-23 17:42:39 -0700
commit644473e9c60c1ff4f6351fed637a6e5551e3dce7 (patch)
tree10316518bedc735a2c6552886658d69dfd9f1eb0 /fs/proc
parentfb827ec68446c83e9e8754fa9b55aed27ecc4661 (diff)
parent4b06a81f1daee668fbd6de85557bfb36dd36078f (diff)
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull user namespace enhancements from Eric Biederman: "This is a course correction for the user namespace, so that we can reach an inexpensive, maintainable, and reasonably complete implementation. Highlights: - Config guards make it impossible to enable the user namespace and code that has not been converted to be user namespace safe. - Use of the new kuid_t type ensures the if you somehow get past the config guards the kernel will encounter type errors if you enable user namespaces and attempt to compile in code whose permission checks have not been updated to be user namespace safe. - All uids from child user namespaces are mapped into the initial user namespace before they are processed. Removing the need to add an additional check to see if the user namespace of the compared uids remains the same. - With the user namespaces compiled out the performance is as good or better than it is today. - For most operations absolutely nothing changes performance or operationally with the user namespace enabled. - The worst case performance I could come up with was timing 1 billion cache cold stat operations with the user namespace code enabled. This went from 156s to 164s on my laptop (or 156ns to 164ns per stat operation). - (uid_t)-1 and (gid_t)-1 are reserved as an internal error value. Most uid/gid setting system calls treat these value specially anyway so attempting to use -1 as a uid would likely cause entertaining failures in userspace. - If setuid is called with a uid that can not be mapped setuid fails. I have looked at sendmail, login, ssh and every other program I could think of that would call setuid and they all check for and handle the case where setuid fails. - If stat or a similar system call is called from a context in which we can not map a uid we lie and return overflowuid. The LFS experience suggests not lying and returning an error code might be better, but the historical precedent with uids is different and I can not think of anything that would break by lying about a uid we can't map. - Capabilities are localized to the current user namespace making it safe to give the initial user in a user namespace all capabilities. My git tree covers all of the modifications needed to convert the core kernel and enough changes to make a system bootable to runlevel 1." Fix up trivial conflicts due to nearby independent changes in fs/stat.c * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (46 commits) userns: Silence silly gcc warning. cred: use correct cred accessor with regards to rcu read lock userns: Convert the move_pages, and migrate_pages permission checks to use uid_eq userns: Convert cgroup permission checks to use uid_eq userns: Convert tmpfs to use kuid and kgid where appropriate userns: Convert sysfs to use kgid/kuid where appropriate userns: Convert sysctl permission checks to use kuid and kgids. userns: Convert proc to use kuid/kgid where appropriate userns: Convert ext4 to user kuid/kgid where appropriate userns: Convert ext3 to use kuid/kgid where appropriate userns: Convert ext2 to use kuid/kgid where appropriate. userns: Convert devpts to use kuid/kgid where appropriate userns: Convert binary formats to use kuid/kgid where appropriate userns: Add negative depends on entries to avoid building code that is userns unsafe userns: signal remove unnecessary map_cred_ns userns: Teach inode_capable to understand inodes whose uids map to other namespaces. userns: Fail exec for suid and sgid binaries with ids outside our user namespace. userns: Convert stat to return values mapped from kuids and kgids userns: Convert user specfied uids and gids in chown into kuids and kgid userns: Use uid_eq gid_eq helpers when comparing kuids and kgids in the vfs ...
Diffstat (limited to 'fs/proc')
-rw-r--r--fs/proc/array.c15
-rw-r--r--fs/proc/base.c93
-rw-r--r--fs/proc/inode.c4
-rw-r--r--fs/proc/proc_sysctl.c4
-rw-r--r--fs/proc/root.c2
5 files changed, 102 insertions, 16 deletions
diff --git a/fs/proc/array.c b/fs/proc/array.c
index f9bd395b3473..dc4c5a7b9ece 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -81,6 +81,7 @@
#include <linux/pid_namespace.h>
#include <linux/ptrace.h>
#include <linux/tracehook.h>
+#include <linux/user_namespace.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
@@ -161,6 +162,7 @@ static inline const char *get_task_state(struct task_struct *tsk)
static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *p)
{
+ struct user_namespace *user_ns = current_user_ns();
struct group_info *group_info;
int g;
struct fdtable *fdt = NULL;
@@ -189,8 +191,14 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
task_tgid_nr_ns(p, ns),
pid_nr_ns(pid, ns),
ppid, tpid,
- cred->uid, cred->euid, cred->suid, cred->fsuid,
- cred->gid, cred->egid, cred->sgid, cred->fsgid);
+ from_kuid_munged(user_ns, cred->uid),
+ from_kuid_munged(user_ns, cred->euid),
+ from_kuid_munged(user_ns, cred->suid),
+ from_kuid_munged(user_ns, cred->fsuid),
+ from_kgid_munged(user_ns, cred->gid),
+ from_kgid_munged(user_ns, cred->egid),
+ from_kgid_munged(user_ns, cred->sgid),
+ from_kgid_munged(user_ns, cred->fsgid));
task_lock(p);
if (p->files)
@@ -205,7 +213,8 @@ static inline void task_state(struct seq_file *m, struct pid_namespace *ns,
task_unlock(p);
for (g = 0; g < min(group_info->ngroups, NGROUPS_SMALL); g++)
- seq_printf(m, "%d ", GROUP_AT(group_info, g));
+ seq_printf(m, "%d ",
+ from_kgid_munged(user_ns, GROUP_AT(group_info, g)));
put_cred(cred);
seq_putc(m, '\n');
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 57b8159f26f3..d2d3108a611c 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -81,6 +81,7 @@
#include <linux/oom.h>
#include <linux/elf.h>
#include <linux/pid_namespace.h>
+#include <linux/user_namespace.h>
#include <linux/fs_struct.h>
#include <linux/slab.h>
#include <linux/flex_array.h>
@@ -1561,8 +1562,8 @@ int pid_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
generic_fillattr(inode, stat);
rcu_read_lock();
- stat->uid = 0;
- stat->gid = 0;
+ stat->uid = GLOBAL_ROOT_UID;
+ stat->gid = GLOBAL_ROOT_GID;
task = pid_task(proc_pid(inode), PIDTYPE_PID);
if (task) {
if (!has_pid_permissions(pid, task, 2)) {
@@ -1622,8 +1623,8 @@ int pid_revalidate(struct dentry *dentry, struct nameidata *nd)
inode->i_gid = cred->egid;
rcu_read_unlock();
} else {
- inode->i_uid = 0;
- inode->i_gid = 0;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
}
inode->i_mode &= ~(S_ISUID | S_ISGID);
security_task_to_inode(task, inode);
@@ -1815,8 +1816,8 @@ static int tid_fd_revalidate(struct dentry *dentry, struct nameidata *nd)
inode->i_gid = cred->egid;
rcu_read_unlock();
} else {
- inode->i_uid = 0;
- inode->i_gid = 0;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
}
i_mode = S_IFLNK;
@@ -2045,8 +2046,8 @@ static int map_files_d_revalidate(struct dentry *dentry, struct nameidata *nd)
inode->i_gid = cred->egid;
rcu_read_unlock();
} else {
- inode->i_uid = 0;
- inode->i_gid = 0;
+ inode->i_uid = GLOBAL_ROOT_UID;
+ inode->i_gid = GLOBAL_ROOT_GID;
}
security_task_to_inode(task, inode);
status = 1;
@@ -2924,6 +2925,74 @@ static int proc_tgid_io_accounting(struct task_struct *task, char *buffer)
}
#endif /* CONFIG_TASK_IO_ACCOUNTING */
+#ifdef CONFIG_USER_NS
+static int proc_id_map_open(struct inode *inode, struct file *file,
+ struct seq_operations *seq_ops)
+{
+ struct user_namespace *ns = NULL;
+ struct task_struct *task;
+ struct seq_file *seq;
+ int ret = -EINVAL;
+
+ task = get_proc_task(inode);
+ if (task) {
+ rcu_read_lock();
+ ns = get_user_ns(task_cred_xxx(task, user_ns));
+ rcu_read_unlock();
+ put_task_struct(task);
+ }
+ if (!ns)
+ goto err;
+
+ ret = seq_open(file, seq_ops);
+ if (ret)
+ goto err_put_ns;
+
+ seq = file->private_data;
+ seq->private = ns;
+
+ return 0;
+err_put_ns:
+ put_user_ns(ns);
+err:
+ return ret;
+}
+
+static int proc_id_map_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct user_namespace *ns = seq->private;
+ put_user_ns(ns);
+ return seq_release(inode, file);
+}
+
+static int proc_uid_map_open(struct inode *inode, struct file *file)
+{
+ return proc_id_map_open(inode, file, &proc_uid_seq_operations);
+}
+
+static int proc_gid_map_open(struct inode *inode, struct file *file)
+{
+ return proc_id_map_open(inode, file, &proc_gid_seq_operations);
+}
+
+static const struct file_operations proc_uid_map_operations = {
+ .open = proc_uid_map_open,
+ .write = proc_uid_map_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = proc_id_map_release,
+};
+
+static const struct file_operations proc_gid_map_operations = {
+ .open = proc_gid_map_open,
+ .write = proc_gid_map_write,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = proc_id_map_release,
+};
+#endif /* CONFIG_USER_NS */
+
static int proc_pid_personality(struct seq_file *m, struct pid_namespace *ns,
struct pid *pid, struct task_struct *task)
{
@@ -3026,6 +3095,10 @@ static const struct pid_entry tgid_base_stuff[] = {
#ifdef CONFIG_HARDWALL
INF("hardwall", S_IRUGO, proc_pid_hardwall),
#endif
+#ifdef CONFIG_USER_NS
+ REG("uid_map", S_IRUGO|S_IWUSR, proc_uid_map_operations),
+ REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations),
+#endif
};
static int proc_tgid_base_readdir(struct file * filp,
@@ -3381,6 +3454,10 @@ static const struct pid_entry tid_base_stuff[] = {
#ifdef CONFIG_HARDWALL
INF("hardwall", S_IRUGO, proc_pid_hardwall),
#endif
+#ifdef CONFIG_USER_NS
+ REG("uid_map", S_IRUGO|S_IWUSR, proc_uid_map_operations),
+ REG("gid_map", S_IRUGO|S_IWUSR, proc_gid_map_operations),
+#endif
};
static int proc_tid_base_readdir(struct file * filp,
diff --git a/fs/proc/inode.c b/fs/proc/inode.c
index 205c92280838..554ecc54799f 100644
--- a/fs/proc/inode.c
+++ b/fs/proc/inode.c
@@ -108,8 +108,8 @@ static int proc_show_options(struct seq_file *seq, struct dentry *root)
struct super_block *sb = root->d_sb;
struct pid_namespace *pid = sb->s_fs_info;
- if (pid->pid_gid)
- seq_printf(seq, ",gid=%lu", (unsigned long)pid->pid_gid);
+ if (!gid_eq(pid->pid_gid, GLOBAL_ROOT_GID))
+ seq_printf(seq, ",gid=%u", from_kgid_munged(&init_user_ns, pid->pid_gid));
if (pid->hide_pid != 0)
seq_printf(seq, ",hidepid=%u", pid->hide_pid);
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index 21d836f40292..3476bca8f7af 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c
@@ -371,9 +371,9 @@ void register_sysctl_root(struct ctl_table_root *root)
static int test_perm(int mode, int op)
{
- if (!current_euid())
+ if (uid_eq(current_euid(), GLOBAL_ROOT_UID))
mode >>= 6;
- else if (in_egroup_p(0))
+ else if (in_egroup_p(GLOBAL_ROOT_GID))
mode >>= 3;
if ((op & ~mode & (MAY_READ|MAY_WRITE|MAY_EXEC)) == 0)
return 0;
diff --git a/fs/proc/root.c b/fs/proc/root.c
index eed44bfc85db..7c30fce037c0 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -67,7 +67,7 @@ static int proc_parse_options(char *options, struct pid_namespace *pid)
case Opt_gid:
if (match_int(&args[0], &option))
return 0;
- pid->pid_gid = option;
+ pid->pid_gid = make_kgid(current_user_ns(), option);
break;
case Opt_hidepid:
if (match_int(&args[0], &option))