Re: [PATCH 23/43] userns: Convert setting and getting uid and gid system calls to use kuid and kgid

Serge E. Hallyn
2012-04-26T16:19:18Z

Quoting Eric W. Beiderman (ebiederm@xmission.com):
> From: Eric W. Biederman <ebiederm@xmission.com>
>
> Convert setregid, setgid, setreuid, setuid,
> setresuid, getresuid, setresgid, getresgid, setfsuid, setfsgid,
> getuid, geteuid, getgid, getegid,
> waitpid, waitid, wait4.
>
> Convert userspace uids and gids into kuids and kgids before
> being placed on struct cred. Convert struct cred kuids and
> kgids into userspace uids and gids when returning them.
>
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
> kernel/exit.c | 6 +-
> kernel/sys.c | 216 ++++++++++++++++++++++++++++++++++++++-----------------
> kernel/timer.c | 8 +-
> kernel/uid16.c | 34 ++++++---
> 4 files changed, 178 insertions(+), 86 deletions(-)
>
> diff --git a/kernel/exit.c b/kernel/exit.c
> index d8bd3b42..789e3c5 100644
> --- a/kernel/exit.c
> +++ b/kernel/exit.c
> @@ -1214,7 +1214,7 @@ static int wait_task_zombie(struct wait_opts *wo, struct task_struct *p)
> unsigned long state;
> int retval, status, traced;
> pid_t pid = task_pid_vnr(p);
> - uid_t uid = __task_cred(p)->uid;
> + uid_t uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
> struct siginfo __user *infop;
>
> if (!likely(wo->wo_flags & WEXITED))
> @@ -1427,7 +1427,7 @@ static int wait_task_stopped(struct wait_opts *wo,
> if (!unlikely(wo->wo_flags & WNOWAIT))
> *p_code = 0;
>
> - uid = task_uid(p);
> + uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
> unlock_sig:
> spin_unlock_irq(&p->sighand->siglock);
> if (!exit_code)
> @@ -1500,7 +1500,7 @@ static int wait_task_continued(struct wait_opts *wo, struct task_struct *p)
> }
> if (!unlikely(wo->wo_flags & WNOWAIT))
> p->signal->flags &= ~SIGNAL_STOP_CONTINUED;
> - uid = task_uid(p);
> + uid = from_kuid_munged(current_user_ns(), __task_cred(p)->uid);
> spin_unlock_irq(&p->sighand->siglock);
>
> pid = task_pid_vnr(p);
> diff --git a/kernel/sys.c b/kernel/sys.c
> index 3996281..aff09f2 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -555,9 +555,19 @@ void ctrl_alt_del(void)
> */
> SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kgid_t krgid, kegid;
> +
> + krgid = make_kgid(ns, rgid);
> + kegid = make_kgid(ns, egid);
> +
> + if ((rgid != (gid_t) -1) && !gid_valid(krgid))
> + return -EINVAL;
> + if ((egid != (gid_t) -1) && !gid_valid(kegid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -566,25 +576,25 @@ SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid)
>
> retval = -EPERM;
> if (rgid != (gid_t) -1) {
> - if (old->gid == rgid ||
> - old->egid == rgid ||
> + if (gid_eq(old->gid, krgid) ||
> + gid_eq(old->egid, krgid) ||
> nsown_capable(CAP_SETGID))
> - new->gid = rgid;
> + new->gid = krgid;
> else
> goto error;
> }
> if (egid != (gid_t) -1) {
> - if (old->gid == egid ||
> - old->egid == egid ||
> - old->sgid == egid ||
> + if (gid_eq(old->gid, kegid) ||
> + gid_eq(old->egid, kegid) ||
> + gid_eq(old->sgid, kegid) ||
> nsown_capable(CAP_SETGID))
> - new->egid = egid;
> + new->egid = kegid;
> else
> goto error;
> }
>
> if (rgid != (gid_t) -1 ||
> - (egid != (gid_t) -1 && egid != old->gid))
> + (egid != (gid_t) -1 && !gid_eq(kegid, old->gid)))
> new->sgid = new->egid;
> new->fsgid = new->egid;
>
> @@ -602,9 +612,15 @@ error:
> */
> SYSCALL_DEFINE1(setgid, gid_t, gid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kgid_t kgid;
> +
> + kgid = make_kgid(ns, gid);
> + if (!gid_valid(kgid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -613,9 +629,9 @@ SYSCALL_DEFINE1(setgid, gid_t, gid)
>
> retval = -EPERM;
> if (nsown_capable(CAP_SETGID))
> - new->gid = new->egid = new->sgid = new->fsgid = gid;
> - else if (gid == old->gid || gid == old->sgid)
> - new->egid = new->fsgid = gid;
> + 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;
> else
> goto error;
>
> @@ -672,9 +688,19 @@ static int set_user(struct cred *new)
> */
> SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kuid_t kruid, keuid;
> +
> + kruid = make_kuid(ns, ruid);
> + keuid = make_kuid(ns, euid);
> +
> + if ((ruid != (uid_t) -1) && !uid_valid(kruid))
> + return -EINVAL;
> + if ((euid != (uid_t) -1) && !uid_valid(keuid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -683,29 +709,29 @@ SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid)
>
> retval = -EPERM;
> if (ruid != (uid_t) -1) {
> - new->uid = ruid;
> - if (old->uid != ruid &&
> - old->euid != ruid &&
> + new->uid = kruid;
> + if (!uid_eq(old->uid, kruid) &&
> + !uid_eq(old->euid, kruid) &&
> !nsown_capable(CAP_SETUID))
> goto error;
> }
>
> if (euid != (uid_t) -1) {
> - new->euid = euid;
> - if (old->uid != euid &&
> - old->euid != euid &&
> - old->suid != euid &&
> + new->euid = keuid;
> + if (!uid_eq(old->uid, keuid) &&
> + !uid_eq(old->euid, keuid) &&
> + !uid_eq(old->suid, keuid) &&
> !nsown_capable(CAP_SETUID))
> goto error;
> }
>
> - if (new->uid != old->uid) {
> + if (!uid_eq(new->uid, old->uid)) {
> retval = set_user(new);
> if (retval < 0)
> goto error;
> }
> if (ruid != (uid_t) -1 ||
> - (euid != (uid_t) -1 && euid != old->uid))
> + (euid != (uid_t) -1 && !uid_eq(keuid, old->uid)))
> new->suid = new->euid;
> new->fsuid = new->euid;
>
> @@ -733,9 +759,15 @@ error:
> */
> SYSCALL_DEFINE1(setuid, uid_t, uid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kuid_t kuid;
> +
> + kuid = make_kuid(ns, uid);
> + if (!uid_valid(kuid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -744,17 +776,17 @@ SYSCALL_DEFINE1(setuid, uid_t, uid)
>
> retval = -EPERM;
> if (nsown_capable(CAP_SETUID)) {
> - new->suid = new->uid = uid;
> - if (uid != old->uid) {
> + new->suid = new->uid = kuid;
> + if (!uid_eq(kuid, old->uid)) {
> retval = set_user(new);
> if (retval < 0)
> goto error;
> }
> - } else if (uid != old->uid && uid != new->suid) {
> + } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) {
> goto error;
> }
>
> - new->fsuid = new->euid = uid;
> + new->fsuid = new->euid = kuid;
>
> retval = security_task_fix_setuid(new, old, LSM_SETID_ID);
> if (retval < 0)
> @@ -774,9 +806,24 @@ error:
> */
> SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kuid_t kruid, keuid, ksuid;
> +
> + kruid = make_kuid(ns, ruid);
> + keuid = make_kuid(ns, euid);
> + ksuid = make_kuid(ns, suid);
> +
> + if ((ruid != (uid_t) -1) && !uid_valid(kruid))
> + return -EINVAL;
> +
> + if ((euid != (uid_t) -1) && !uid_valid(keuid))
> + return -EINVAL;
> +
> + if ((suid != (uid_t) -1) && !uid_valid(ksuid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -786,29 +833,29 @@ SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid)
>
> retval = -EPERM;
> if (!nsown_capable(CAP_SETUID)) {
> - if (ruid != (uid_t) -1 && ruid != old->uid &&
> - ruid != old->euid && ruid != old->suid)
> + if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) &&
> + !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid))
> goto error;
> - if (euid != (uid_t) -1 && euid != old->uid &&
> - euid != old->euid && euid != old->suid)
> + if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) &&
> + !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid))
> goto error;
> - if (suid != (uid_t) -1 && suid != old->uid &&
> - suid != old->euid && suid != old->suid)
> + if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) &&
> + !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid))
> goto error;
> }
>
> if (ruid != (uid_t) -1) {
> - new->uid = ruid;
> - if (ruid != old->uid) {
> + new->uid = kruid;
> + if (!uid_eq(kruid, old->uid)) {
> retval = set_user(new);
> if (retval < 0)
> goto error;
> }
> }
> if (euid != (uid_t) -1)
> - new->euid = euid;
> + new->euid = keuid;
> if (suid != (uid_t) -1)
> - new->suid = suid;
> + new->suid = ksuid;
> new->fsuid = new->euid;
>
> retval = security_task_fix_setuid(new, old, LSM_SETID_RES);
> @@ -822,14 +869,19 @@ error:
> return retval;
> }
>
> -SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __user *, suid)
> +SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp)
> {
> const struct cred *cred = current_cred();
> int retval;
> + uid_t ruid, euid, suid;
> +
> + ruid = from_kuid_munged(cred->user_ns, cred->uid);
> + euid = from_kuid_munged(cred->user_ns, cred->euid);
> + suid = from_kuid_munged(cred->user_ns, cred->suid);
>
> - if (!(retval = put_user(cred->uid, ruid)) &&
> - !(retval = put_user(cred->euid, euid)))
> - retval = put_user(cred->suid, suid);
> + if (!(retval = put_user(ruid, ruidp)) &&
> + !(retval = put_user(euid, euidp)))
> + retval = put_user(suid, suidp);
>
> return retval;
> }
> @@ -839,9 +891,22 @@ SYSCALL_DEFINE3(getresuid, uid_t __user *, ruid, uid_t __user *, euid, uid_t __u
> */
> SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
> {
> + struct user_namespace *ns = current_user_ns();
> const struct cred *old;
> struct cred *new;
> int retval;
> + kgid_t krgid, kegid, ksgid;
> +
> + krgid = make_kgid(ns, rgid);
> + kegid = make_kgid(ns, egid);
> + ksgid = make_kgid(ns, sgid);
> +
> + if ((rgid != (gid_t) -1) && !gid_valid(krgid))
> + return -EINVAL;
> + if ((egid != (gid_t) -1) && !gid_valid(kegid))
> + return -EINVAL;
> + if ((sgid != (gid_t) -1) && !gid_valid(ksgid))
> + return -EINVAL;
>
> new = prepare_creds();
> if (!new)
> @@ -850,23 +915,23 @@ SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid)
>
> retval = -EPERM;
> if (!nsown_capable(CAP_SETGID)) {
> - if (rgid != (gid_t) -1 && rgid != old->gid &&
> - rgid != old->egid && rgid != old->sgid)
> + if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) &&
> + !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid))
> goto error;
> - if (egid != (gid_t) -1 && egid != old->gid &&
> - egid != old->egid && egid != old->sgid)
> + if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) &&
> + !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid))
> goto error;
> - if (sgid != (gid_t) -1 && sgid != old->gid &&
> - sgid != old->egid && sgid != old->sgid)
> + if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) &&
> + !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid))
> goto error;
> }
>
> if (rgid != (gid_t) -1)
> - new->gid = rgid;
> + new->gid = krgid;
> if (egid != (gid_t) -1)
> - new->egid = egid;
> + new->egid = kegid;
> if (sgid != (gid_t) -1)
> - new->sgid = sgid;
> + new->sgid = ksgid;
> new->fsgid = new->egid;
>
> return commit_creds(new);
> @@ -876,14 +941,19 @@ error:
> return retval;
> }
>
> -SYSCALL_DEFINE3(getresgid, gid_t __user *, rgid, gid_t __user *, egid, gid_t __user *, sgid)
> +SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp)
> {
> const struct cred *cred = current_cred();
> int retval;
> + gid_t rgid, egid, sgid;
> +
> + rgid = from_kgid_munged(cred->user_ns, cred->gid);
> + egid = from_kgid_munged(cred->user_ns, cred->egid);
> + sgid = from_kgid_munged(cred->user_ns, cred->sgid);
>
> - if (!(retval = put_user(cred->gid, rgid)) &&
> - !(retval = put_user(cred->egid, egid)))
> - retval = put_user(cred->sgid, sgid);
> + if (!(retval = put_user(rgid, rgidp)) &&
> + !(retval = put_user(egid, egidp)))
> + retval = put_user(sgid, sgidp);
>
> return retval;
> }
> @@ -900,18 +970,24 @@ SYSCALL_DEFINE1(setfsuid, uid_t, uid)
> const struct cred *old;
> struct cred *new;
> uid_t old_fsuid;
> + kuid_t kuid;
> +
> + old = current_cred();
> + old_fsuid = from_kuid_munged(old->user_ns, old->fsuid);
> +
> + kuid = make_kuid(old->user_ns, uid);
> + if (!uid_valid(kuid))
> + return old_fsuid;
>
> new = prepare_creds();
> if (!new)
> - return current_fsuid();
> - old = current_cred();
> - old_fsuid = old->fsuid;
> + return old_fsuid;
>
> - if (uid == old->uid || uid == old->euid ||
> - uid == old->suid || uid == old->fsuid ||
> + 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)) {
> - if (uid != old_fsuid) {
> - new->fsuid = uid;
> + if (!uid_eq(kuid, old->fsuid)) {
> + new->fsuid = kuid;
> if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0)
> goto change_okay;
> }
> @@ -933,18 +1009,24 @@ SYSCALL_DEFINE1(setfsgid, gid_t, gid)
> const struct cred *old;
> struct cred *new;
> gid_t old_fsgid;
> + kgid_t kgid;
> +
> + old = current_cred();
> + old_fsgid = from_kgid_munged(old->user_ns, old->fsgid);
> +
> + kgid = make_kgid(old->user_ns, gid);
> + if (!gid_valid(kgid))
> + return old_fsgid;
>
> new = prepare_creds();
> if (!new)
> - return current_fsgid();
> - old = current_cred();
> - old_fsgid = old->fsgid;
> + return old_fsgid;
>
> - if (gid == old->gid || gid == old->egid ||
> - gid == old->sgid || gid == old->fsgid ||
> + 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)) {
> - if (gid != old_fsgid) {
> - new->fsgid = gid;
> + if (!gid_eq(kgid, old->fsgid)) {
> + new->fsgid = kgid;
> goto change_okay;
> }
> }
> @@ -1503,10 +1585,10 @@ static int check_prlimit_permission(struct task_struct *task)
> if (cred->user_ns == tcred->user_ns &&
> (cred->uid == tcred->euid &&
> cred->uid == tcred->suid &&
> - cred->uid == tcred->uid &&
> + cred->uid == tcred->uid &&
> cred->gid == tcred->egid &&
> cred->gid == tcred->sgid &&
> - cred->gid == tcred->gid))
> + cred->gid == tcred->gid))
> return 0;
> if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE))
> return 0;
> diff --git a/kernel/timer.c b/kernel/timer.c
> index a297ffc..67316cb 100644
> --- a/kernel/timer.c
> +++ b/kernel/timer.c
> @@ -1427,25 +1427,25 @@ SYSCALL_DEFINE0(getppid)
> SYSCALL_DEFINE0(getuid)
> {
> /* Only we change this so SMP safe */
> - return current_uid();
> + return from_kuid_munged(current_user_ns(), current_uid());
> }
>
> SYSCALL_DEFINE0(geteuid)
> {
> /* Only we change this so SMP safe */
> - return current_euid();
> + return from_kuid_munged(current_user_ns(), current_euid());
> }
>
> SYSCALL_DEFINE0(getgid)
> {
> /* Only we change this so SMP safe */
> - return current_gid();
> + return from_kgid_munged(current_user_ns(), current_gid());
> }
>
> SYSCALL_DEFINE0(getegid)
> {
> /* Only we change this so SMP safe */
> - return current_egid();
> + return from_kgid_munged(current_user_ns(), current_egid());
> }
>
> #endif
> diff --git a/kernel/uid16.c b/kernel/uid16.c
> index e530bc3..d7948eb 100644
> --- a/kernel/uid16.c
> +++ b/kernel/uid16.c
> @@ -81,14 +81,19 @@ SYSCALL_DEFINE3(setresuid16, old_uid_t, ruid, old_uid_t, euid, old_uid_t, suid)
> return ret;
> }
>
> -SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruid, old_uid_t __user *, euid, old_uid_t __user *, suid)
> +SYSCALL_DEFINE3(getresuid16, old_uid_t __user *, ruidp, old_uid_t __user *, euidp, old_uid_t __user *, suidp)
> {
> const struct cred *cred = current_cred();
> int retval;
> + old_uid_t ruid, euid, suid;
>
> - if (!(retval = put_user(high2lowuid(cred->uid), ruid)) &&
> - !(retval = put_user(high2lowuid(cred->euid), euid)))
> - retval = put_user(high2lowuid(cred->suid), suid);
> + ruid = high2lowuid(from_kuid_munged(cred->user_ns, cred->uid));
> + euid = high2lowuid(from_kuid_munged(cred->user_ns, cred->euid));
> + suid = high2lowuid(from_kuid_munged(cred->user_ns, cred->suid));
> +
> + if (!(retval = put_user(ruid, ruidp)) &&
> + !(retval = put_user(euid, euidp)))
> + retval = put_user(suid, suidp);
>
> return retval;
> }
> @@ -103,14 +108,19 @@ SYSCALL_DEFINE3(setresgid16, old_gid_t, rgid, old_gid_t, egid, old_gid_t, sgid)
> }
>
>
> -SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgid, old_gid_t __user *, egid, old_gid_t __user *, sgid)
> +SYSCALL_DEFINE3(getresgid16, old_gid_t __user *, rgidp, old_gid_t __user *, egidp, old_gid_t __user *, sgidp)
> {
> const struct cred *cred = current_cred();
> int retval;
> + old_gid_t rgid, egid, sgid;
> +
> + rgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->gid));
> + egid = high2lowgid(from_kgid_munged(cred->user_ns, cred->egid));
> + sgid = high2lowgid(from_kgid_munged(cred->user_ns, cred->sgid));
>
> - if (!(retval = put_user(high2lowgid(cred->gid), rgid)) &&
> - !(retval = put_user(high2lowgid(cred->egid), egid)))
> - retval = put_user(high2lowgid(cred->sgid), sgid);
> + if (!(retval = put_user(rgid, rgidp)) &&
> + !(retval = put_user(egid, egidp)))
> + retval = put_user(sgid, sgidp);
>
> return retval;
> }
> @@ -221,20 +231,20 @@ SYSCALL_DEFINE2(setgroups16, int, gidsetsize, old_gid_t __user *, grouplist)
>
> SYSCALL_DEFINE0(getuid16)
> {
> - return high2lowuid(current_uid());
> + return high2lowuid(from_kuid_munged(current_user_ns(), current_uid()));
> }
>
> SYSCALL_DEFINE0(geteuid16)
> {
> - return high2lowuid(current_euid());
> + return high2lowuid(from_kuid_munged(current_user_ns(), current_euid()));
> }
>
> SYSCALL_DEFINE0(getgid16)
> {
> - return high2lowgid(current_gid());
> + return high2lowgid(from_kgid_munged(current_user_ns(), current_gid()));
> }
>
> SYSCALL_DEFINE0(getegid16)
> {
> - return high2lowgid(current_egid());
> + return high2lowgid(from_kgid_munged(current_user_ns(), current_egid()));
> }
> --
> 1.7.2.5
>
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