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Diffstat (limited to 'pkg/sentry/kernel/task_identity.go')
-rw-r--r--pkg/sentry/kernel/task_identity.go220
1 files changed, 119 insertions, 101 deletions
diff --git a/pkg/sentry/kernel/task_identity.go b/pkg/sentry/kernel/task_identity.go
index 39c138925..78ff14b20 100644
--- a/pkg/sentry/kernel/task_identity.go
+++ b/pkg/sentry/kernel/task_identity.go
@@ -25,30 +25,22 @@ import (
//
// This value must be considered immutable.
func (t *Task) Credentials() *auth.Credentials {
- t.mu.Lock()
- defer t.mu.Unlock()
- return t.creds
+ return t.creds.Load()
}
// UserNamespace returns the user namespace associated with the task.
func (t *Task) UserNamespace() *auth.UserNamespace {
- t.mu.Lock()
- defer t.mu.Unlock()
- return t.creds.UserNamespace
+ return t.Credentials().UserNamespace
}
// HasCapabilityIn checks if the task has capability cp in user namespace ns.
func (t *Task) HasCapabilityIn(cp linux.Capability, ns *auth.UserNamespace) bool {
- t.mu.Lock()
- defer t.mu.Unlock()
- return t.creds.HasCapabilityIn(cp, ns)
+ return t.Credentials().HasCapabilityIn(cp, ns)
}
// HasCapability checks if the task has capability cp in its user namespace.
func (t *Task) HasCapability(cp linux.Capability) bool {
- t.mu.Lock()
- defer t.mu.Unlock()
- return t.creds.HasCapability(cp)
+ return t.Credentials().HasCapability(cp)
}
// SetUID implements the semantics of setuid(2).
@@ -57,9 +49,12 @@ func (t *Task) SetUID(uid auth.UID) error {
if !uid.Ok() {
return syserror.EINVAL
}
+
t.mu.Lock()
defer t.mu.Unlock()
- kuid := t.creds.UserNamespace.MapToKUID(uid)
+
+ creds := t.Credentials()
+ kuid := creds.UserNamespace.MapToKUID(uid)
if !kuid.Ok() {
return syserror.EINVAL
}
@@ -67,17 +62,17 @@ func (t *Task) SetUID(uid auth.UID) error {
// effective UID of the caller is root (more precisely: if the caller has
// the CAP_SETUID capability), the real UID and saved set-user-ID are also
// set." - setuid(2)
- if t.creds.HasCapability(linux.CAP_SETUID) {
+ if creds.HasCapability(linux.CAP_SETUID) {
t.setKUIDsUncheckedLocked(kuid, kuid, kuid)
return nil
}
// "EPERM: The user is not privileged (Linux: does not have the CAP_SETUID
// capability) and uid does not match the real UID or saved set-user-ID of
// the calling process."
- if kuid != t.creds.RealKUID && kuid != t.creds.SavedKUID {
+ if kuid != creds.RealKUID && kuid != creds.SavedKUID {
return syserror.EPERM
}
- t.setKUIDsUncheckedLocked(t.creds.RealKUID, kuid, t.creds.SavedKUID)
+ t.setKUIDsUncheckedLocked(creds.RealKUID, kuid, creds.SavedKUID)
return nil
}
@@ -87,37 +82,38 @@ func (t *Task) SetREUID(r, e auth.UID) error {
defer t.mu.Unlock()
// "Supplying a value of -1 for either the real or effective user ID forces
// the system to leave that ID unchanged." - setreuid(2)
- newR := t.creds.RealKUID
+ creds := t.Credentials()
+ newR := creds.RealKUID
if r.Ok() {
- newR = t.creds.UserNamespace.MapToKUID(r)
+ newR = creds.UserNamespace.MapToKUID(r)
if !newR.Ok() {
return syserror.EINVAL
}
}
- newE := t.creds.EffectiveKUID
+ newE := creds.EffectiveKUID
if e.Ok() {
- newE = t.creds.UserNamespace.MapToKUID(e)
+ newE = creds.UserNamespace.MapToKUID(e)
if !newE.Ok() {
return syserror.EINVAL
}
}
- if !t.creds.HasCapability(linux.CAP_SETUID) {
+ if !creds.HasCapability(linux.CAP_SETUID) {
// "Unprivileged processes may only set the effective user ID to the
// real user ID, the effective user ID, or the saved set-user-ID."
- if newE != t.creds.RealKUID && newE != t.creds.EffectiveKUID && newE != t.creds.SavedKUID {
+ if newE != creds.RealKUID && newE != creds.EffectiveKUID && newE != creds.SavedKUID {
return syserror.EPERM
}
// "Unprivileged users may only set the real user ID to the real user
// ID or the effective user ID."
- if newR != t.creds.RealKUID && newR != t.creds.EffectiveKUID {
+ if newR != creds.RealKUID && newR != creds.EffectiveKUID {
return syserror.EPERM
}
}
// "If the real user ID is set (i.e., ruid is not -1) or the effective user
// ID is set to a value not equal to the previous real user ID, the saved
// set-user-ID will be set to the new effective user ID."
- newS := t.creds.SavedKUID
- if r.Ok() || (e.Ok() && newE != t.creds.EffectiveKUID) {
+ newS := creds.SavedKUID
+ if r.Ok() || (e.Ok() && newE != creds.EffectiveKUID) {
newS = newE
}
t.setKUIDsUncheckedLocked(newR, newE, newS)
@@ -136,23 +132,24 @@ func (t *Task) SetRESUID(r, e, s auth.UID) error {
// arguments equals -1, the corresponding value is not changed." -
// setresuid(2)
var err error
- newR := t.creds.RealKUID
+ creds := t.Credentials()
+ newR := creds.RealKUID
if r.Ok() {
- newR, err = t.creds.UseUID(r)
+ newR, err = creds.UseUID(r)
if err != nil {
return err
}
}
- newE := t.creds.EffectiveKUID
+ newE := creds.EffectiveKUID
if e.Ok() {
- newE, err = t.creds.UseUID(e)
+ newE, err = creds.UseUID(e)
if err != nil {
return err
}
}
- newS := t.creds.SavedKUID
+ newS := creds.SavedKUID
if s.Ok() {
- newS, err = t.creds.UseUID(s)
+ newS, err = creds.UseUID(s)
if err != nil {
return err
}
@@ -163,10 +160,10 @@ func (t *Task) SetRESUID(r, e, s auth.UID) error {
// Preconditions: t.mu must be locked.
func (t *Task) setKUIDsUncheckedLocked(newR, newE, newS auth.KUID) {
- root := t.creds.UserNamespace.MapToKUID(auth.RootUID)
- oldR, oldE, oldS := t.creds.RealKUID, t.creds.EffectiveKUID, t.creds.SavedKUID
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.RealKUID, t.creds.EffectiveKUID, t.creds.SavedKUID = newR, newE, newS
+ creds := t.Credentials().Fork() // The credentials object is immutable. See doc for creds.
+ root := creds.UserNamespace.MapToKUID(auth.RootUID)
+ oldR, oldE, oldS := creds.RealKUID, creds.EffectiveKUID, creds.SavedKUID
+ creds.RealKUID, creds.EffectiveKUID, creds.SavedKUID = newR, newE, newS
// "1. If one or more of the real, effective or saved set user IDs was
// previously 0, and as a result of the UID changes all of these IDs have a
@@ -184,9 +181,9 @@ func (t *Task) setKUIDsUncheckedLocked(newR, newE, newS auth.KUID) {
// being cleared." (A thread's effective capability set is always
// cleared when such a credential change is made,
// regardless of the setting of the "keep capabilities" flag.)
- if !t.creds.KeepCaps {
- t.creds.PermittedCaps = 0
- t.creds.EffectiveCaps = 0
+ if !creds.KeepCaps {
+ creds.PermittedCaps = 0
+ creds.EffectiveCaps = 0
}
}
// """
@@ -197,9 +194,9 @@ func (t *Task) setKUIDsUncheckedLocked(newR, newE, newS auth.KUID) {
// permitted set is copied to the effective set.
// """
if oldE == root && newE != root {
- t.creds.EffectiveCaps = 0
+ creds.EffectiveCaps = 0
} else if oldE != root && newE == root {
- t.creds.EffectiveCaps = t.creds.PermittedCaps
+ creds.EffectiveCaps = creds.PermittedCaps
}
// "4. If the filesystem user ID is changed from 0 to nonzero (see
// setfsuid(2)), then the following capabilities are cleared from the
@@ -220,6 +217,7 @@ func (t *Task) setKUIDsUncheckedLocked(newR, newE, newS auth.KUID) {
// Not documented, but compare Linux's kernel/cred.c:commit_creds().
t.parentDeathSignal = 0
}
+ t.creds.Store(creds)
}
// SetGID implements the semantics of setgid(2).
@@ -227,20 +225,23 @@ func (t *Task) SetGID(gid auth.GID) error {
if !gid.Ok() {
return syserror.EINVAL
}
+
t.mu.Lock()
defer t.mu.Unlock()
- kgid := t.creds.UserNamespace.MapToKGID(gid)
+
+ creds := t.Credentials()
+ kgid := creds.UserNamespace.MapToKGID(gid)
if !kgid.Ok() {
return syserror.EINVAL
}
- if t.creds.HasCapability(linux.CAP_SETGID) {
+ if creds.HasCapability(linux.CAP_SETGID) {
t.setKGIDsUncheckedLocked(kgid, kgid, kgid)
return nil
}
- if kgid != t.creds.RealKGID && kgid != t.creds.SavedKGID {
+ if kgid != creds.RealKGID && kgid != creds.SavedKGID {
return syserror.EPERM
}
- t.setKGIDsUncheckedLocked(t.creds.RealKGID, kgid, t.creds.SavedKGID)
+ t.setKGIDsUncheckedLocked(creds.RealKGID, kgid, creds.SavedKGID)
return nil
}
@@ -248,30 +249,32 @@ func (t *Task) SetGID(gid auth.GID) error {
func (t *Task) SetREGID(r, e auth.GID) error {
t.mu.Lock()
defer t.mu.Unlock()
- newR := t.creds.RealKGID
+
+ creds := t.Credentials()
+ newR := creds.RealKGID
if r.Ok() {
- newR = t.creds.UserNamespace.MapToKGID(r)
+ newR = creds.UserNamespace.MapToKGID(r)
if !newR.Ok() {
return syserror.EINVAL
}
}
- newE := t.creds.EffectiveKGID
+ newE := creds.EffectiveKGID
if e.Ok() {
- newE = t.creds.UserNamespace.MapToKGID(e)
+ newE = creds.UserNamespace.MapToKGID(e)
if !newE.Ok() {
return syserror.EINVAL
}
}
- if !t.creds.HasCapability(linux.CAP_SETGID) {
- if newE != t.creds.RealKGID && newE != t.creds.EffectiveKGID && newE != t.creds.SavedKGID {
+ if !creds.HasCapability(linux.CAP_SETGID) {
+ if newE != creds.RealKGID && newE != creds.EffectiveKGID && newE != creds.SavedKGID {
return syserror.EPERM
}
- if newR != t.creds.RealKGID && newR != t.creds.EffectiveKGID {
+ if newR != creds.RealKGID && newR != creds.EffectiveKGID {
return syserror.EPERM
}
}
- newS := t.creds.SavedKGID
- if r.Ok() || (e.Ok() && newE != t.creds.EffectiveKGID) {
+ newS := creds.SavedKGID
+ if r.Ok() || (e.Ok() && newE != creds.EffectiveKGID) {
newS = newE
}
t.setKGIDsUncheckedLocked(newR, newE, newS)
@@ -280,26 +283,29 @@ func (t *Task) SetREGID(r, e auth.GID) error {
// SetRESGID implements the semantics of the setresgid(2) syscall.
func (t *Task) SetRESGID(r, e, s auth.GID) error {
+ var err error
+
t.mu.Lock()
defer t.mu.Unlock()
- var err error
- newR := t.creds.RealKGID
+
+ creds := t.Credentials()
+ newR := creds.RealKGID
if r.Ok() {
- newR, err = t.creds.UseGID(r)
+ newR, err = creds.UseGID(r)
if err != nil {
return err
}
}
- newE := t.creds.EffectiveKGID
+ newE := creds.EffectiveKGID
if e.Ok() {
- newE, err = t.creds.UseGID(e)
+ newE, err = creds.UseGID(e)
if err != nil {
return err
}
}
- newS := t.creds.SavedKGID
+ newS := creds.SavedKGID
if s.Ok() {
- newS, err = t.creds.UseGID(s)
+ newS, err = creds.UseGID(s)
if err != nil {
return err
}
@@ -309,9 +315,9 @@ func (t *Task) SetRESGID(r, e, s auth.GID) error {
}
func (t *Task) setKGIDsUncheckedLocked(newR, newE, newS auth.KGID) {
- oldE := t.creds.EffectiveKGID
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.RealKGID, t.creds.EffectiveKGID, t.creds.SavedKGID = newR, newE, newS
+ creds := t.Credentials().Fork() // The credentials object is immutable. See doc for creds.
+ oldE := creds.EffectiveKGID
+ creds.RealKGID, creds.EffectiveKGID, creds.SavedKGID = newR, newE, newS
if oldE != newE {
// "[dumpability] is reset to the current value contained in
@@ -327,6 +333,7 @@ func (t *Task) setKGIDsUncheckedLocked(newR, newE, newS auth.KGID) {
// kernel/cred.c:commit_creds().
t.parentDeathSignal = 0
}
+ t.creds.Store(creds)
}
// SetExtraGIDs attempts to change t's supplemental groups. All IDs are
@@ -334,19 +341,21 @@ func (t *Task) setKGIDsUncheckedLocked(newR, newE, newS auth.KGID) {
func (t *Task) SetExtraGIDs(gids []auth.GID) error {
t.mu.Lock()
defer t.mu.Unlock()
- if !t.creds.HasCapability(linux.CAP_SETGID) {
+ creds := t.Credentials()
+ if !creds.HasCapability(linux.CAP_SETGID) {
return syserror.EPERM
}
kgids := make([]auth.KGID, len(gids))
for i, gid := range gids {
- kgid := t.creds.UserNamespace.MapToKGID(gid)
+ kgid := creds.UserNamespace.MapToKGID(gid)
if !kgid.Ok() {
return syserror.EINVAL
}
kgids[i] = kgid
}
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.ExtraKGIDs = kgids
+ creds = creds.Fork() // The credentials object is immutable. See doc for creds.
+ creds.ExtraKGIDs = kgids
+ t.creds.Store(creds)
return nil
}
@@ -360,27 +369,29 @@ func (t *Task) SetCapabilitySets(permitted, inheritable, effective auth.Capabili
if effective & ^permitted != 0 {
return syserror.EPERM
}
+ creds := t.Credentials()
// "It is also a limiting superset for the capabilities that may be added
// to the inheritable set by a thread that does not have the CAP_SETPCAP
// capability in its effective set."
- if !t.creds.HasCapability(linux.CAP_SETPCAP) && (inheritable & ^(t.creds.InheritableCaps|t.creds.PermittedCaps) != 0) {
+ if !creds.HasCapability(linux.CAP_SETPCAP) && (inheritable & ^(creds.InheritableCaps|creds.PermittedCaps) != 0) {
return syserror.EPERM
}
// "If a thread drops a capability from its permitted set, it can never
// reacquire that capability (unless it execve(2)s ..."
- if permitted & ^t.creds.PermittedCaps != 0 {
+ if permitted & ^creds.PermittedCaps != 0 {
return syserror.EPERM
}
// "... if a capability is not in the bounding set, then a thread can't add
// this capability to its inheritable set, even if it was in its permitted
// capabilities ..."
- if inheritable & ^(t.creds.InheritableCaps|t.creds.BoundingCaps) != 0 {
+ if inheritable & ^(creds.InheritableCaps|creds.BoundingCaps) != 0 {
return syserror.EPERM
}
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.PermittedCaps = permitted
- t.creds.InheritableCaps = inheritable
- t.creds.EffectiveCaps = effective
+ creds = creds.Fork() // The credentials object is immutable. See doc for creds.
+ creds.PermittedCaps = permitted
+ creds.InheritableCaps = inheritable
+ creds.EffectiveCaps = effective
+ t.creds.Store(creds)
return nil
}
@@ -389,11 +400,13 @@ func (t *Task) SetCapabilitySets(permitted, inheritable, effective auth.Capabili
func (t *Task) DropBoundingCapability(cp linux.Capability) error {
t.mu.Lock()
defer t.mu.Unlock()
- if !t.creds.HasCapability(linux.CAP_SETPCAP) {
+ creds := t.Credentials()
+ if !creds.HasCapability(linux.CAP_SETPCAP) {
return syserror.EPERM
}
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.BoundingCaps &^= auth.CapabilitySetOf(cp)
+ creds = creds.Fork() // The credentials object is immutable. See doc for creds.
+ creds.BoundingCaps &^= auth.CapabilitySetOf(cp)
+ t.creds.Store(creds)
return nil
}
@@ -402,31 +415,33 @@ func (t *Task) SetUserNamespace(ns *auth.UserNamespace) error {
t.mu.Lock()
defer t.mu.Unlock()
+ creds := t.Credentials()
// "A process reassociating itself with a user namespace must have the
// CAP_SYS_ADMIN capability in the target user namespace." - setns(2)
//
// If t just created ns, then t.creds is guaranteed to have CAP_SYS_ADMIN
// in ns (by rule 3 in auth.Credentials.HasCapability).
- if !t.creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, ns) {
+ if !creds.HasCapabilityIn(linux.CAP_SYS_ADMIN, ns) {
return syserror.EPERM
}
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.UserNamespace = ns
+ creds = creds.Fork() // The credentials object is immutable. See doc for creds.
+ creds.UserNamespace = ns
// "The child process created by clone(2) with the CLONE_NEWUSER flag
// starts out with a complete set of capabilities in the new user
// namespace. Likewise, a process that creates a new user namespace using
// unshare(2) or joins an existing user namespace using setns(2) gains a
// full set of capabilities in that namespace."
- t.creds.PermittedCaps = auth.AllCapabilities
- t.creds.InheritableCaps = 0
- t.creds.EffectiveCaps = auth.AllCapabilities
- t.creds.BoundingCaps = auth.AllCapabilities
+ creds.PermittedCaps = auth.AllCapabilities
+ creds.InheritableCaps = 0
+ creds.EffectiveCaps = auth.AllCapabilities
+ creds.BoundingCaps = auth.AllCapabilities
// "A call to clone(2), unshare(2), or setns(2) using the CLONE_NEWUSER
// flag sets the "securebits" flags (see capabilities(7)) to their default
// values (all flags disabled) in the child (for clone(2)) or caller (for
// unshare(2), or setns(2)." - user_namespaces(7)
- t.creds.KeepCaps = false
+ creds.KeepCaps = false
+ t.creds.Store(creds)
return nil
}
@@ -435,8 +450,9 @@ func (t *Task) SetUserNamespace(ns *auth.UserNamespace) error {
func (t *Task) SetKeepCaps(k bool) {
t.mu.Lock()
defer t.mu.Unlock()
- t.creds = t.creds.Fork() // See doc for creds.
- t.creds.KeepCaps = k
+ creds := t.Credentials().Fork() // The credentials object is immutable. See doc for creds.
+ creds.KeepCaps = k
+ t.creds.Store(creds)
}
// updateCredsForExec updates t.creds to reflect an execve().
@@ -512,15 +528,16 @@ func (t *Task) updateCredsForExecLocked() {
// the effective user ID.
var newPermitted auth.CapabilitySet // since F(inheritable) == F(permitted) == 0
fileEffective := false
- root := t.creds.UserNamespace.MapToKUID(auth.RootUID)
- if t.creds.EffectiveKUID == root || t.creds.RealKUID == root {
- newPermitted = t.creds.InheritableCaps | t.creds.BoundingCaps
- if t.creds.EffectiveKUID == root {
+ creds := t.Credentials()
+ root := creds.UserNamespace.MapToKUID(auth.RootUID)
+ if creds.EffectiveKUID == root || creds.RealKUID == root {
+ newPermitted = creds.InheritableCaps | creds.BoundingCaps
+ if creds.EffectiveKUID == root {
fileEffective = true
}
}
- t.creds = t.creds.Fork() // See doc for creds.
+ creds = creds.Fork() // The credentials object is immutable. See doc for creds.
// Now we enter poorly-documented, somewhat confusing territory. (The
// accompanying comment in Linux's security/commoncap.c:cap_bprm_set_creds
@@ -562,27 +579,28 @@ func (t *Task) updateCredsForExecLocked() {
// But since no_new_privs is always set (A3 is always true), this becomes
// much simpler. If B1 and B2 are false, C2 is a no-op. If B3 is false, C1
// is a no-op. So we can just do C1 and C2 unconditionally.
- if t.creds.EffectiveKUID != t.creds.RealKUID || t.creds.EffectiveKGID != t.creds.RealKGID {
- t.creds.EffectiveKUID = t.creds.RealKUID
- t.creds.EffectiveKGID = t.creds.RealKGID
+ if creds.EffectiveKUID != creds.RealKUID || creds.EffectiveKGID != creds.RealKGID {
+ creds.EffectiveKUID = creds.RealKUID
+ creds.EffectiveKGID = creds.RealKGID
t.parentDeathSignal = 0
}
// (Saved set-user-ID is always set to the new effective user ID, and saved
// set-group-ID is always set to the new effective group ID, regardless of
// the above.)
- t.creds.SavedKUID = t.creds.RealKUID
- t.creds.SavedKGID = t.creds.RealKGID
- t.creds.PermittedCaps &= newPermitted
+ creds.SavedKUID = creds.RealKUID
+ creds.SavedKGID = creds.RealKGID
+ creds.PermittedCaps &= newPermitted
if fileEffective {
- t.creds.EffectiveCaps = t.creds.PermittedCaps
+ creds.EffectiveCaps = creds.PermittedCaps
} else {
- t.creds.EffectiveCaps = 0
+ creds.EffectiveCaps = 0
}
// prctl(2): The "keep capabilities" value will be reset to 0 on subsequent
// calls to execve(2).
- t.creds.KeepCaps = false
+ creds.KeepCaps = false
// "The bounding set is inherited at fork(2) from the thread's parent, and
// is preserved across an execve(2)". So we're done.
+ t.creds.Store(creds)
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-29 22:22:30 +0000