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userns: Kill nsown_capable it makes the wrong thing easy
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nsown_capable is a special case of ns_capable essentially for just CAP_SETUID and
CAP_SETGID.  For the existing users it doesn't noticably simplify things and
from the suggested patches I have seen it encourages people to do the wrong
thing.  So remove nsown_capable.

Acked-by: Serge Hallyn <[email protected]>
Signed-off-by: "Eric W. Biederman" <[email protected]>
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@ebiederm
ebiederm committed Aug 31, 2013
1 parent f54fb86 commit c7b96ac
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Showing 12 changed files with 21 additions and 34 deletions.
4 changes: 2 additions & 2 deletions fs/namespace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2929,8 +2929,8 @@ static int mntns_install(struct nsproxy *nsproxy, void *ns)
struct path root;

if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
!nsown_capable(CAP_SYS_CHROOT) ||
!nsown_capable(CAP_SYS_ADMIN))
!ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;

if (fs->users != 1)
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2 changes: 1 addition & 1 deletion fs/open.c
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Original file line number Diff line number Diff line change
Expand Up @@ -443,7 +443,7 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename)
goto dput_and_out;

error = -EPERM;
if (!nsown_capable(CAP_SYS_CHROOT))
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
goto dput_and_out;
error = security_path_chroot(&path);
if (error)
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1 change: 0 additions & 1 deletion include/linux/capability.h
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Original file line number Diff line number Diff line change
Expand Up @@ -210,7 +210,6 @@ extern bool has_ns_capability_noaudit(struct task_struct *t,
struct user_namespace *ns, int cap);
extern bool capable(int cap);
extern bool ns_capable(struct user_namespace *ns, int cap);
extern bool nsown_capable(int cap);
extern bool inode_capable(const struct inode *inode, int cap);
extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap);

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2 changes: 1 addition & 1 deletion ipc/namespace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -171,7 +171,7 @@ static int ipcns_install(struct nsproxy *nsproxy, void *new)
{
struct ipc_namespace *ns = new;
if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
!nsown_capable(CAP_SYS_ADMIN))
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;

/* Ditch state from the old ipc namespace */
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12 changes: 0 additions & 12 deletions kernel/capability.c
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Original file line number Diff line number Diff line change
Expand Up @@ -432,18 +432,6 @@ bool capable(int cap)
}
EXPORT_SYMBOL(capable);

/**
* nsown_capable - Check superior capability to one's own user_ns
* @cap: The capability in question
*
* Return true if the current task has the given superior capability
* targeted at its own user namespace.
*/
bool nsown_capable(int cap)
{
return ns_capable(current_user_ns(), cap);
}

/**
* inode_capable - Check superior capability over inode
* @inode: The inode in question
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2 changes: 1 addition & 1 deletion kernel/groups.c
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Original file line number Diff line number Diff line change
Expand Up @@ -233,7 +233,7 @@ SYSCALL_DEFINE2(setgroups, int, gidsetsize, gid_t __user *, grouplist)
struct group_info *group_info;
int retval;

if (!nsown_capable(CAP_SETGID))
if (!ns_capable(current_user_ns(), CAP_SETGID))
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
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2 changes: 1 addition & 1 deletion kernel/pid_namespace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -329,7 +329,7 @@ static int pidns_install(struct nsproxy *nsproxy, void *ns)
struct pid_namespace *ancestor, *new = ns;

if (!ns_capable(new->user_ns, CAP_SYS_ADMIN) ||
!nsown_capable(CAP_SYS_ADMIN))
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;

/*
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20 changes: 10 additions & 10 deletions kernel/sys.c
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Original file line number Diff line number Diff line change
Expand Up @@ -337,7 +337,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
if (rgid != (gid_t) -1) {
if (gid_eq(old->gid, krgid) ||
gid_eq(old->egid, krgid) ||
nsown_capable(CAP_SETGID))
ns_capable(old->user_ns, CAP_SETGID))
new->gid = krgid;
else
goto error;
Expand All @@ -346,7 +346,7 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
if (gid_eq(old->gid, kegid) ||
gid_eq(old->egid, kegid) ||
gid_eq(old->sgid, kegid) ||
nsown_capable(CAP_SETGID))
ns_capable(old->user_ns, CAP_SETGID))
new->egid = kegid;
else
goto error;
Expand Down Expand Up @@ -387,7 +387,7 @@ SYSCALL_DEFINE1(setgid, gid_t, gid)
old = current_cred();

retval = -EPERM;
if (nsown_capable(CAP_SETGID))
if (ns_capable(old->user_ns, CAP_SETGID))
new->gid = new->egid = new->sgid = new->fsgid = kgid;
else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid))
new->egid = new->fsgid = kgid;
Expand Down Expand Up @@ -471,7 +471,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
new->uid = kruid;
if (!uid_eq(old->uid, kruid) &&
!uid_eq(old->euid, kruid) &&
!nsown_capable(CAP_SETUID))
!ns_capable(old->user_ns, CAP_SETUID))
goto error;
}

Expand All @@ -480,7 +480,7 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
if (!uid_eq(old->uid, keuid) &&
!uid_eq(old->euid, keuid) &&
!uid_eq(old->suid, keuid) &&
!nsown_capable(CAP_SETUID))
!ns_capable(old->user_ns, CAP_SETUID))
goto error;
}

Expand Down Expand Up @@ -534,7 +534,7 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
old = current_cred();

retval = -EPERM;
if (nsown_capable(CAP_SETUID)) {
if (ns_capable(old->user_ns, CAP_SETUID)) {
new->suid = new->uid = kuid;
if (!uid_eq(kuid, old->uid)) {
retval = set_user(new);
Expand Down Expand Up @@ -591,7 +591,7 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
old = current_cred();

retval = -EPERM;
if (!nsown_capable(CAP_SETUID)) {
if (!ns_capable(old->user_ns, CAP_SETUID)) {
if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
!uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
goto error;
Expand Down Expand Up @@ -673,7 +673,7 @@ SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
old = current_cred();

retval = -EPERM;
if (!nsown_capable(CAP_SETGID)) {
if (!ns_capable(old->user_ns, CAP_SETGID)) {
if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
!gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
goto error;
Expand Down Expand Up @@ -744,7 +744,7 @@ SYSCALL_DEFINE1(setfsuid, uid_t, uid)

if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) ||
uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) ||
nsown_capable(CAP_SETUID)) {
ns_capable(old->user_ns, CAP_SETUID)) {
if (!uid_eq(kuid, old->fsuid)) {
new->fsuid = kuid;
if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
Expand Down Expand Up @@ -783,7 +783,7 @@ SYSCALL_DEFINE1(setfsgid, gid_t, gid)

if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) ||
gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) ||
nsown_capable(CAP_SETGID)) {
ns_capable(old->user_ns, CAP_SETGID)) {
if (!gid_eq(kgid, old->fsgid)) {
new->fsgid = kgid;
goto change_okay;
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2 changes: 1 addition & 1 deletion kernel/uid16.c
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Original file line number Diff line number Diff line change
Expand Up @@ -176,7 +176,7 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
struct group_info *group_info;
int retval;

if (!nsown_capable(CAP_SETGID))
if (!ns_capable(current_user_ns(), CAP_SETGID))
return -EPERM;
if ((unsigned)gidsetsize > NGROUPS_MAX)
return -EINVAL;
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2 changes: 1 addition & 1 deletion kernel/utsname.c
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Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ static int utsns_install(struct nsproxy *nsproxy, void *new)
struct uts_namespace *ns = new;

if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN) ||
!nsown_capable(CAP_SYS_ADMIN))
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;

get_uts_ns(ns);
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2 changes: 1 addition & 1 deletion net/core/net_namespace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -651,7 +651,7 @@ static int netns_install(struct nsproxy *nsproxy, void *ns)
struct net *net = ns;

if (!ns_capable(net->user_ns, CAP_SYS_ADMIN) ||
!nsown_capable(CAP_SYS_ADMIN))
!ns_capable(current_user_ns(), CAP_SYS_ADMIN))
return -EPERM;

put_net(nsproxy->net_ns);
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4 changes: 2 additions & 2 deletions net/core/scm.c
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Original file line number Diff line number Diff line change
Expand Up @@ -56,9 +56,9 @@ static __inline__ int scm_check_creds(struct ucred *creds)
if ((creds->pid == task_tgid_vnr(current) ||
ns_capable(current->nsproxy->pid_ns->user_ns, CAP_SYS_ADMIN)) &&
((uid_eq(uid, cred->uid) || uid_eq(uid, cred->euid) ||
uid_eq(uid, cred->suid)) || nsown_capable(CAP_SETUID)) &&
uid_eq(uid, cred->suid)) || ns_capable(cred->user_ns, CAP_SETUID)) &&
((gid_eq(gid, cred->gid) || gid_eq(gid, cred->egid) ||
gid_eq(gid, cred->sgid)) || nsown_capable(CAP_SETGID))) {
gid_eq(gid, cred->sgid)) || ns_capable(cred->user_ns, CAP_SETGID))) {
return 0;
}
return -EPERM;
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