[PATCH v4 2/2] LSM: SafeSetID: gate setgid transitions
James Morris
jmorris at namei.org
Mon Mar 11 18:38:56 UTC 2019
On Mon, 11 Mar 2019, Micah Morton wrote:
> Is this ready to be merged if there are no further comments?
Nothing gets merged to the subsystem trees until the main merge window is
closed (i.e. v5.1-rc1).
I'd expect / hope for more review of this to happen, too.
>
> On Tue, Mar 5, 2019 at 7:52 AM <mortonm at chromium.org> wrote:
> >
> > From: Micah Morton <mortonm at chromium.org>
> >
> > The SafeSetID LSM already gates setuid transitions for UIDs on the
> > system whose use of CAP_SETUID has been 'restricted'. This patch
> > implements the analogous functionality for setgid transitions, in order
> > to restrict the use of CAP_SETGID for certain UIDs on the system. One
> > notable consequence of this addition is that a process running under a
> > restricted UID (i.e. one that is only allowed to setgid to certain
> > approved GIDs) will not be allowed to call the setgroups() syscall to
> > set its supplementary group IDs. For now, we leave such support for
> > restricted setgroups() to future work, as it would require hooking the
> > logic in setgroups() and verifying that the array of GIDs passed in from
> > userspace only consists of approved GIDs.
> >
> > Signed-off-by: Micah Morton <mortonm at chromium.org>
> > ---
> > Changes since the last patch: Minor updates since patch 1/2 combined the
> > 'task_fix_setuid' and 'task_fix_setgid' hooks into one hook called
> > 'task_fix_setid'.
> >
> > Documentation/admin-guide/LSM/SafeSetID.rst | 9 +-
> > security/safesetid/lsm.c | 272 +++++++++++++++++---
> > security/safesetid/lsm.h | 11 +-
> > security/safesetid/securityfs.c | 105 +++++---
> > 4 files changed, 320 insertions(+), 77 deletions(-)
> >
> > diff --git a/Documentation/admin-guide/LSM/SafeSetID.rst b/Documentation/admin-guide/LSM/SafeSetID.rst
> > index 670a6544fd39..33307a8e9555 100644
> > --- a/Documentation/admin-guide/LSM/SafeSetID.rst
> > +++ b/Documentation/admin-guide/LSM/SafeSetID.rst
> > @@ -98,10 +98,13 @@ Directions for use
> > ==================
> > This LSM hooks the setid syscalls to make sure transitions are allowed if an
> > applicable restriction policy is in place. Policies are configured through
> > -securityfs by writing to the safesetid/add_whitelist_policy and
> > +securityfs by writing to the safesetid/add_whitelist_{uid/gid}_policy* and
> > safesetid/flush_whitelist_policies files at the location where securityfs is
> > -mounted. The format for adding a policy is '<UID>:<UID>', using literal
> > +mounted. The format for adding a policy is '<ID>:<ID>', using literal
> > numbers, such as '123:456'. To flush the policies, any write to the file is
> > sufficient. Again, configuring a policy for a UID will prevent that UID from
> > obtaining auxiliary setid privileges, such as allowing a user to set up user
> > -namespace UID mappings.
> > +namespace ID mappings.
> > +
> > +*safesetid/add_whitelist_policy can also be used for UID policies, since it is
> > +an alias for safesetid/add_whitelist_uid_policy
> > diff --git a/security/safesetid/lsm.c b/security/safesetid/lsm.c
> > index 5deffa92f25f..95c6f35b29f3 100644
> > --- a/security/safesetid/lsm.c
> > +++ b/security/safesetid/lsm.c
> > @@ -26,27 +26,30 @@ int safesetid_initialized;
> >
> > #define NUM_BITS 8 /* 128 buckets in hash table */
> >
> > -static DEFINE_HASHTABLE(safesetid_whitelist_hashtable, NUM_BITS);
> > +static DEFINE_HASHTABLE(safesetid_whitelist_uid_hashtable, NUM_BITS);
> > +static DEFINE_HASHTABLE(safesetid_whitelist_gid_hashtable, NUM_BITS);
> > +
> > +static DEFINE_SPINLOCK(safesetid_whitelist_uid_hashtable_spinlock);
> > +static DEFINE_SPINLOCK(safesetid_whitelist_gid_hashtable_spinlock);
> >
> > /*
> > * Hash table entry to store safesetid policy signifying that 'parent' user
> > - * can setid to 'child' user.
> > + * can setid to 'child' user. This struct is used in both the uid and gid
> > + * hashtables.
> > */
> > -struct entry {
> > +struct id_entry {
> > struct hlist_node next;
> > struct hlist_node dlist; /* for deletion cleanup */
> > uint64_t parent_kuid;
> > - uint64_t child_kuid;
> > + uint64_t child_kid; /* Represents either a UID or a GID */
> > };
> >
> > -static DEFINE_SPINLOCK(safesetid_whitelist_hashtable_spinlock);
> > -
> > static bool check_setuid_policy_hashtable_key(kuid_t parent)
> > {
> > - struct entry *entry;
> > + struct id_entry *entry;
> >
> > rcu_read_lock();
> > - hash_for_each_possible_rcu(safesetid_whitelist_hashtable,
> > + hash_for_each_possible_rcu(safesetid_whitelist_uid_hashtable,
> > entry, next, __kuid_val(parent)) {
> > if (entry->parent_kuid == __kuid_val(parent)) {
> > rcu_read_unlock();
> > @@ -61,13 +64,49 @@ static bool check_setuid_policy_hashtable_key(kuid_t parent)
> > static bool check_setuid_policy_hashtable_key_value(kuid_t parent,
> > kuid_t child)
> > {
> > - struct entry *entry;
> > + struct id_entry *entry;
> > +
> > + rcu_read_lock();
> > + hash_for_each_possible_rcu(safesetid_whitelist_uid_hashtable,
> > + entry, next, __kuid_val(parent)) {
> > + if (entry->parent_kuid == __kuid_val(parent) &&
> > + entry->child_kid == __kuid_val(child)) {
> > + rcu_read_unlock();
> > + return true;
> > + }
> > + }
> > + rcu_read_unlock();
> > +
> > + return false;
> > +}
> > +
> > +static bool check_setgid_policy_hashtable_key(kuid_t parent)
> > +{
> > + struct id_entry *entry;
> > +
> > + rcu_read_lock();
> > + hash_for_each_possible_rcu(safesetid_whitelist_gid_hashtable,
> > + entry, next, __kuid_val(parent)) {
> > + if (entry->parent_kuid == __kuid_val(parent)) {
> > + rcu_read_unlock();
> > + return true;
> > + }
> > + }
> > + rcu_read_unlock();
> > +
> > + return false;
> > +}
> > +
> > +static bool check_setgid_policy_hashtable_key_value(kuid_t parent,
> > + kgid_t child)
> > +{
> > + struct id_entry *entry;
> >
> > rcu_read_lock();
> > - hash_for_each_possible_rcu(safesetid_whitelist_hashtable,
> > + hash_for_each_possible_rcu(safesetid_whitelist_gid_hashtable,
> > entry, next, __kuid_val(parent)) {
> > if (entry->parent_kuid == __kuid_val(parent) &&
> > - entry->child_kuid == __kuid_val(child)) {
> > + entry->child_kid == __kgid_val(child)) {
> > rcu_read_unlock();
> > return true;
> > }
> > @@ -77,6 +116,12 @@ static bool check_setuid_policy_hashtable_key_value(kuid_t parent,
> > return false;
> > }
> >
> > +/*
> > + * This hook causes the security_capable check to fail when there are
> > + * restriction policies for a UID and the process is trying to do something
> > + * (other than a setid transition) that is gated by CAP_SETUID/CAP_SETGID
> > + * (e.g. allowing user to set up userns UID/GID mappings).
> > + */
> > static int safesetid_security_capable(const struct cred *cred,
> > struct user_namespace *ns,
> > int cap,
> > @@ -85,17 +130,19 @@ static int safesetid_security_capable(const struct cred *cred,
> > if (cap == CAP_SETUID &&
> > check_setuid_policy_hashtable_key(cred->uid)) {
> > if (!(opts & CAP_OPT_INSETID)) {
> > - /*
> > - * Deny if we're not in a set*uid() syscall to avoid
> > - * giving powers gated by CAP_SETUID that are related
> > - * to functionality other than calling set*uid() (e.g.
> > - * allowing user to set up userns uid mappings).
> > - */
> > pr_warn("Operation requires CAP_SETUID, which is not available to UID %u for operations besides approved set*uid transitions",
> > __kuid_val(cred->uid));
> > return -1;
> > }
> > }
> > + if (cap == CAP_SETGID &&
> > + check_setgid_policy_hashtable_key(cred->uid)) {
> > + if (!(opts & CAP_OPT_INSETID)) {
> > + pr_warn("Operation requires CAP_SETGID, which is not available to UID %u for operations besides approved set*gid transitions",
> > + __kuid_val(cred->uid));
> > + return -1;
> > + }
> > + }
> > return 0;
> > }
> >
> > @@ -115,19 +162,48 @@ static int check_uid_transition(kuid_t parent, kuid_t child)
> > return -EACCES;
> > }
> >
> > +static int check_gid_transition(kuid_t parent, kgid_t child)
> > +{
> > + if (check_setgid_policy_hashtable_key_value(parent, child))
> > + return 0;
> > + pr_warn("Denied UID %d setting GID to %d",
> > + __kuid_val(parent),
> > + __kgid_val(child));
> > + /*
> > + * Kill this process to avoid potential security vulnerabilities
> > + * that could arise from a missing whitelist entry preventing a
> > + * privileged process from dropping to a lesser-privileged one.
> > + */
> > + force_sig(SIGKILL, current);
> > + return -EACCES;
> > +}
> > +
> > /*
> > * Check whether there is either an exception for user under old cred struct to
> > - * set*uid to user under new cred struct, or the UID transition is allowed (by
> > - * Linux set*uid rules) even without CAP_SETUID.
> > + * set*id to user under new cred struct, or the ID transition is allowed (by
> > + * Linux set*id rules) even without CAP_SET*ID.
> > */
> > static int safesetid_task_fix_setid(struct cred *new,
> > const struct cred *old,
> > int flags)
> > {
> > + if (flags == LSM_SETUID_RE ||
> > + flags == LSM_SETUID_ID ||
> > + flags == LSM_SETUID_RES ||
> > + flags == LSM_SETUID_FS) {
> > + /* Do nothing if there are no setuid restrictions for this UID. */
> > + if (!check_setuid_policy_hashtable_key(old->uid))
> > + return 0;
> > + }
> >
> > - /* Do nothing if there are no setuid restrictions for this UID. */
> > - if (!check_setuid_policy_hashtable_key(old->uid))
> > + if (flags == LSM_SETGID_RE ||
> > + flags == LSM_SETGID_ID ||
> > + flags == LSM_SETGID_RES ||
> > + flags == LSM_SETGID_FS) {
> > + /* Do nothing if there are no setgid restrictions for this UID. */
> > + if (!check_setgid_policy_hashtable_key(old->uid))
> > return 0;
> > + }
> >
> > switch (flags) {
> > case LSM_SETUID_RE:
> > @@ -201,6 +277,77 @@ static int safesetid_task_fix_setid(struct cred *new,
> > return check_uid_transition(old->fsuid, new->fsuid);
> > }
> > break;
> > + case LSM_SETGID_RE:
> > + /*
> > + * Users for which setgid restrictions exist can only set the
> > + * real GID to the real GID or the effective GID, unless an
> > + * explicit whitelist policy allows the transition.
> > + */
> > + if (!gid_eq(old->gid, new->gid) &&
> > + !gid_eq(old->egid, new->gid)) {
> > + return check_gid_transition(old->uid, new->gid);
> > + }
> > + /*
> > + * Users for which setgid restrictions exist can only set the
> > + * effective GID to the real GID, the effective GID, or the
> > + * saved set-GID, unless an explicit whitelist policy allows
> > + * the transition.
> > + */
> > + if (!gid_eq(old->gid, new->egid) &&
> > + !gid_eq(old->egid, new->egid) &&
> > + !gid_eq(old->sgid, new->egid)) {
> > + return check_gid_transition(old->euid, new->egid);
> > + }
> > + break;
> > + case LSM_SETGID_ID:
> > + /*
> > + * Users for which setgid restrictions exist cannot change the
> > + * real GID or saved set-GID unless an explicit whitelist
> > + * policy allows the transition.
> > + */
> > + if (!gid_eq(old->gid, new->gid))
> > + return check_gid_transition(old->uid, new->gid);
> > + if (!gid_eq(old->sgid, new->sgid))
> > + return check_gid_transition(old->suid, new->sgid);
> > + break;
> > + case LSM_SETGID_RES:
> > + /*
> > + * Users for which setgid restrictions exist cannot change the
> > + * real GID, effective GID, or saved set-GID to anything but
> > + * one of: the current real GID, the current effective GID or
> > + * the current saved set-user-ID unless an explicit whitelist
> > + * policy allows the transition.
> > + */
> > + if (!gid_eq(new->gid, old->gid) &&
> > + !gid_eq(new->gid, old->egid) &&
> > + !gid_eq(new->gid, old->sgid)) {
> > + return check_gid_transition(old->uid, new->gid);
> > + }
> > + if (!gid_eq(new->egid, old->gid) &&
> > + !gid_eq(new->egid, old->egid) &&
> > + !gid_eq(new->egid, old->sgid)) {
> > + return check_gid_transition(old->euid, new->egid);
> > + }
> > + if (!gid_eq(new->sgid, old->gid) &&
> > + !gid_eq(new->sgid, old->egid) &&
> > + !gid_eq(new->sgid, old->sgid)) {
> > + return check_gid_transition(old->suid, new->sgid);
> > + }
> > + break;
> > + case LSM_SETGID_FS:
> > + /*
> > + * Users for which setgid restrictions exist cannot change the
> > + * filesystem GID to anything but one of: the current real GID,
> > + * the current effective GID or the current saved set-GID
> > + * unless an explicit whitelist policy allows the transition.
> > + */
> > + if (!gid_eq(new->fsgid, old->gid) &&
> > + !gid_eq(new->fsgid, old->egid) &&
> > + !gid_eq(new->fsgid, old->sgid) &&
> > + !gid_eq(new->fsgid, old->fsgid)) {
> > + return check_gid_transition(old->fsuid, new->fsgid);
> > + }
> > + break;
> > default:
> > pr_warn("Unknown setid state %d\n", flags);
> > force_sig(SIGKILL, current);
> > @@ -209,49 +356,96 @@ static int safesetid_task_fix_setid(struct cred *new,
> > return 0;
> > }
> >
> > -int add_safesetid_whitelist_entry(kuid_t parent, kuid_t child)
> > +int add_safesetid_whitelist_uid_entry(kuid_t parent, kuid_t child)
> > {
> > - struct entry *new;
> > + struct id_entry *new;
> >
> > /* Return if entry already exists */
> > if (check_setuid_policy_hashtable_key_value(parent, child))
> > return 0;
> >
> > - new = kzalloc(sizeof(struct entry), GFP_KERNEL);
> > + new = kzalloc(sizeof(struct id_entry), GFP_KERNEL);
> > + if (!new)
> > + return -ENOMEM;
> > + new->parent_kuid = __kuid_val(parent);
> > + new->child_kid = __kuid_val(child);
> > + spin_lock(&safesetid_whitelist_uid_hashtable_spinlock);
> > + /* Return if the entry got added since we checked above */
> > + if (check_setuid_policy_hashtable_key_value(parent, child)) {
> > + spin_unlock(&safesetid_whitelist_uid_hashtable_spinlock);
> > + kfree(new);
> > + return 0;
> > + }
> > + hash_add_rcu(safesetid_whitelist_uid_hashtable,
> > + &new->next,
> > + __kuid_val(parent));
> > + spin_unlock(&safesetid_whitelist_uid_hashtable_spinlock);
> > + return 0;
> > +}
> > +
> > +int add_safesetid_whitelist_gid_entry(kuid_t parent, kgid_t child)
> > +{
> > + struct id_entry *new;
> > +
> > + /* Return if entry already exists */
> > + if (check_setgid_policy_hashtable_key_value(parent, child))
> > + return 0;
> > +
> > + new = kzalloc(sizeof(struct id_entry), GFP_KERNEL);
> > if (!new)
> > return -ENOMEM;
> > new->parent_kuid = __kuid_val(parent);
> > - new->child_kuid = __kuid_val(child);
> > - spin_lock(&safesetid_whitelist_hashtable_spinlock);
> > - hash_add_rcu(safesetid_whitelist_hashtable,
> > + new->child_kid = __kgid_val(child);
> > + spin_lock(&safesetid_whitelist_gid_hashtable_spinlock);
> > + /* Return if the entry got added since we checked above */
> > + if (check_setgid_policy_hashtable_key_value(parent, child)) {
> > + spin_unlock(&safesetid_whitelist_gid_hashtable_spinlock);
> > + kfree(new);
> > + return 0;
> > + }
> > + hash_add_rcu(safesetid_whitelist_gid_hashtable,
> > &new->next,
> > __kuid_val(parent));
> > - spin_unlock(&safesetid_whitelist_hashtable_spinlock);
> > + spin_unlock(&safesetid_whitelist_gid_hashtable_spinlock);
> > return 0;
> > }
> >
> > void flush_safesetid_whitelist_entries(void)
> > {
> > - struct entry *entry;
> > + struct id_entry *id_entry;
> > struct hlist_node *hlist_node;
> > unsigned int bkt_loop_cursor;
> > - HLIST_HEAD(free_list);
> > + HLIST_HEAD(uid_free_list);
> > + HLIST_HEAD(gid_free_list);
> >
> > /*
> > * Could probably use hash_for_each_rcu here instead, but this should
> > * be fine as well.
> > */
> > - spin_lock(&safesetid_whitelist_hashtable_spinlock);
> > - hash_for_each_safe(safesetid_whitelist_hashtable, bkt_loop_cursor,
> > - hlist_node, entry, next) {
> > - hash_del_rcu(&entry->next);
> > - hlist_add_head(&entry->dlist, &free_list);
> > + spin_lock(&safesetid_whitelist_uid_hashtable_spinlock);
> > + hash_for_each_safe(safesetid_whitelist_uid_hashtable, bkt_loop_cursor,
> > + hlist_node, id_entry, next) {
> > + hash_del_rcu(&id_entry->next);
> > + hlist_add_head(&id_entry->dlist, &uid_free_list);
> > + }
> > + spin_unlock(&safesetid_whitelist_uid_hashtable_spinlock);
> > + synchronize_rcu();
> > + hlist_for_each_entry_safe(id_entry, hlist_node, &uid_free_list, dlist) {
> > + hlist_del(&id_entry->dlist);
> > + kfree(id_entry);
> > + }
> > +
> > + spin_lock(&safesetid_whitelist_gid_hashtable_spinlock);
> > + hash_for_each_safe(safesetid_whitelist_gid_hashtable, bkt_loop_cursor,
> > + hlist_node, id_entry, next) {
> > + hash_del_rcu(&id_entry->next);
> > + hlist_add_head(&id_entry->dlist, &gid_free_list);
> > }
> > - spin_unlock(&safesetid_whitelist_hashtable_spinlock);
> > + spin_unlock(&safesetid_whitelist_gid_hashtable_spinlock);
> > synchronize_rcu();
> > - hlist_for_each_entry_safe(entry, hlist_node, &free_list, dlist) {
> > - hlist_del(&entry->dlist);
> > - kfree(entry);
> > + hlist_for_each_entry_safe(id_entry, hlist_node, &gid_free_list, dlist) {
> > + hlist_del(&id_entry->dlist);
> > + kfree(id_entry);
> > }
> > }
> >
> > diff --git a/security/safesetid/lsm.h b/security/safesetid/lsm.h
> > index c1ea3c265fcf..e9ae192caff2 100644
> > --- a/security/safesetid/lsm.h
> > +++ b/security/safesetid/lsm.h
> > @@ -21,13 +21,16 @@ extern int safesetid_initialized;
> >
> > /* Function type. */
> > enum safesetid_whitelist_file_write_type {
> > - SAFESETID_WHITELIST_ADD, /* Add whitelist policy. */
> > + SAFESETID_WHITELIST_ADD_UID, /* Add UID whitelist policy. */
> > + SAFESETID_WHITELIST_ADD_GID, /* Add GID whitelist policy. */
> > SAFESETID_WHITELIST_FLUSH, /* Flush whitelist policies. */
> > };
> >
> > -/* Add entry to safesetid whitelist to allow 'parent' to setid to 'child'. */
> > -int add_safesetid_whitelist_entry(kuid_t parent, kuid_t child);
> > -
> > +/* Add entry to safesetid whitelist to allow 'parent' to setuid to 'child'. */
> > +int add_safesetid_whitelist_uid_entry(kuid_t parent, kuid_t child);
> > +/* Add entry to safesetid whitelist to allow 'parent' to setgid to 'child'. */
> > +int add_safesetid_whitelist_gid_entry(kgid_t parent, kgid_t child);
> > +/* Flush all UID/GID whitelist policies. */
> > void flush_safesetid_whitelist_entries(void);
> >
> > #endif /* _SAFESETID_H */
> > diff --git a/security/safesetid/securityfs.c b/security/safesetid/securityfs.c
> > index 2c6c829be044..c4c25ba7275f 100644
> > --- a/security/safesetid/securityfs.c
> > +++ b/security/safesetid/securityfs.c
> > @@ -26,20 +26,19 @@ struct safesetid_file_entry {
> >
> > static struct safesetid_file_entry safesetid_files[] = {
> > {.name = "add_whitelist_policy",
> > - .type = SAFESETID_WHITELIST_ADD},
> > + .type = SAFESETID_WHITELIST_ADD_UID},
> > + {.name = "add_whitelist_uid_policy",
> > + .type = SAFESETID_WHITELIST_ADD_UID},
> > + {.name = "add_whitelist_gid_policy",
> > + .type = SAFESETID_WHITELIST_ADD_GID},
> > {.name = "flush_whitelist_policies",
> > .type = SAFESETID_WHITELIST_FLUSH},
> > };
> >
> > -/*
> > - * In the case the input buffer contains one or more invalid UIDs, the kuid_t
> > - * variables pointed to by 'parent' and 'child' will get updated but this
> > - * function will return an error.
> > - */
> > -static int parse_safesetid_whitelist_policy(const char __user *buf,
> > +static int parse_userbuf_to_longs(const char __user *buf,
> > size_t len,
> > - kuid_t *parent,
> > - kuid_t *child)
> > + long *parent,
> > + long *child)
> > {
> > char *kern_buf;
> > char *parent_buf;
> > @@ -47,8 +46,6 @@ static int parse_safesetid_whitelist_policy(const char __user *buf,
> > const char separator[] = ":";
> > int ret;
> > size_t first_substring_length;
> > - long parsed_parent;
> > - long parsed_child;
> >
> > /* Duplicate string from user memory and NULL-terminate */
> > kern_buf = memdup_user_nul(buf, len);
> > @@ -71,27 +68,15 @@ static int parse_safesetid_whitelist_policy(const char __user *buf,
> > goto free_kern;
> > }
> >
> > - ret = kstrtol(parent_buf, 0, &parsed_parent);
> > + ret = kstrtol(parent_buf, 0, parent);
> > if (ret)
> > goto free_both;
> >
> > child_buf = kern_buf + first_substring_length + 1;
> > - ret = kstrtol(child_buf, 0, &parsed_child);
> > + ret = kstrtol(child_buf, 0, child);
> > if (ret)
> > goto free_both;
> >
> > - *parent = make_kuid(current_user_ns(), parsed_parent);
> > - if (!uid_valid(*parent)) {
> > - ret = -EINVAL;
> > - goto free_both;
> > - }
> > -
> > - *child = make_kuid(current_user_ns(), parsed_child);
> > - if (!uid_valid(*child)) {
> > - ret = -EINVAL;
> > - goto free_both;
> > - }
> > -
> > free_both:
> > kfree(parent_buf);
> > free_kern:
> > @@ -99,6 +84,52 @@ static int parse_safesetid_whitelist_policy(const char __user *buf,
> > return ret;
> > }
> >
> > +static int parse_safesetid_whitelist_uid_policy(const char __user *buf,
> > + size_t len,
> > + kuid_t *parent_uid,
> > + kuid_t *child_uid)
> > +{
> > + int ret;
> > + long parent, child;
> > +
> > + ret = parse_userbuf_to_longs(buf, len, &parent, &child);
> > + if (ret)
> > + return ret;
> > +
> > + *parent_uid = make_kuid(current_user_ns(), parent);
> > + if (!uid_valid(*parent_uid))
> > + return -EINVAL;
> > +
> > + *child_uid = make_kuid(current_user_ns(), child);
> > + if (!uid_valid(*child_uid))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > +static int parse_safesetid_whitelist_gid_policy(const char __user *buf,
> > + size_t len,
> > + kgid_t *parent_gid,
> > + kgid_t *child_gid)
> > +{
> > + int ret;
> > + long parent, child;
> > +
> > + ret = parse_userbuf_to_longs(buf, len, &parent, &child);
> > + if (ret)
> > + return ret;
> > +
> > + *parent_gid = make_kgid(current_user_ns(), parent);
> > + if (!gid_valid(*parent_gid))
> > + return -EINVAL;
> > +
> > + *child_gid = make_kgid(current_user_ns(), child);
> > + if (!gid_valid(*child_gid))
> > + return -EINVAL;
> > +
> > + return 0;
> > +}
> > +
> > static ssize_t safesetid_file_write(struct file *file,
> > const char __user *buf,
> > size_t len,
> > @@ -106,8 +137,10 @@ static ssize_t safesetid_file_write(struct file *file,
> > {
> > struct safesetid_file_entry *file_entry =
> > file->f_inode->i_private;
> > - kuid_t parent;
> > - kuid_t child;
> > + kuid_t uid_parent;
> > + kuid_t uid_child;
> > + kgid_t gid_parent;
> > + kgid_t gid_child;
> > int ret;
> >
> > if (!ns_capable(current_user_ns(), CAP_MAC_ADMIN))
> > @@ -120,13 +153,23 @@ static ssize_t safesetid_file_write(struct file *file,
> > case SAFESETID_WHITELIST_FLUSH:
> > flush_safesetid_whitelist_entries();
> > break;
> > - case SAFESETID_WHITELIST_ADD:
> > - ret = parse_safesetid_whitelist_policy(buf, len, &parent,
> > - &child);
> > + case SAFESETID_WHITELIST_ADD_UID:
> > + ret = parse_safesetid_whitelist_uid_policy(buf, len, &uid_parent,
> > + &uid_child);
> > + if (ret)
> > + return ret;
> > +
> > + ret = add_safesetid_whitelist_uid_entry(uid_parent, uid_child);
> > + if (ret)
> > + return ret;
> > + break;
> > + case SAFESETID_WHITELIST_ADD_GID:
> > + ret = parse_safesetid_whitelist_gid_policy(buf, len, &gid_parent,
> > + &gid_child);
> > if (ret)
> > return ret;
> >
> > - ret = add_safesetid_whitelist_entry(parent, child);
> > + ret = add_safesetid_whitelist_gid_entry(gid_parent, gid_child);
> > if (ret)
> > return ret;
> > break;
> > --
> > 2.21.0.352.gf09ad66450-goog
> >
>
--
James Morris
<jmorris at namei.org>
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