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Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 26/27] keys: Allow containers to be included in key ACLs by name From: David Howells To: keyrings@vger.kernel.org, trond.myklebust@hammerspace.com, sfrench@samba.org Cc: linux-security-module@vger.kernel.org, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-fsdevel@vger.kernel.org, rgb@redhat.com, dhowells@redhat.com, linux-kernel@vger.kernel.org Date: Fri, 15 Feb 2019 16:12:09 +0000 Message-ID: <155024712939.21651.14094051420890992278.stgit@warthog.procyon.org.uk> In-Reply-To: <155024683432.21651.14153938339749694146.stgit@warthog.procyon.org.uk> References: <155024683432.21651.14153938339749694146.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Fri, 15 Feb 2019 16:12:12 +0000 (UTC) Sender: linux-cifs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org Allow a container to be specified to KEYCTL_GRANT_PERMISSION by name. This allows processes that don't have access to the container fd to grant permission on a key to a container. This is restricted to the containers that are children of the current container. This can be effected with something like: keyctl(KEYCTL_GRANT_PERMISSION, key, KEY_ACE_SUBJ_CONTAINER_NAME, "foo-test", KEY_ACE_SEARCH); Signed-off-by: David Howells --- include/linux/container.h | 1 + include/uapi/linux/keyctl.h | 1 + kernel/container.c | 24 ++++++++++++++++++++++++ security/keys/compat.c | 4 ++++ security/keys/internal.h | 2 +- security/keys/keyctl.c | 2 +- security/keys/permission.c | 19 ++++++++++++++++++- 7 files changed, 50 insertions(+), 3 deletions(-) diff --git a/include/linux/container.h b/include/linux/container.h index cd82074c26a3..fd49ce23467d 100644 --- a/include/linux/container.h +++ b/include/linux/container.h @@ -61,6 +61,7 @@ extern struct container init_container; #ifdef CONFIG_CONTAINERS extern const struct file_operations container_fops; +extern struct container *find_container(const char *name); extern int copy_container(unsigned long flags, struct task_struct *tsk, struct container *container); extern void exit_container(struct task_struct *tsk); diff --git a/include/uapi/linux/keyctl.h b/include/uapi/linux/keyctl.h index 89ab609f774c..31520da17f37 100644 --- a/include/uapi/linux/keyctl.h +++ b/include/uapi/linux/keyctl.h @@ -21,6 +21,7 @@ enum key_ace_subject_type { KEY_ACE_SUBJ_STANDARD = 0, /* subject is one of key_ace_standard_subject */ KEY_ACE_SUBJ_CONTAINER = 1, /* subject is a container fd */ + KEY_ACE_SUBJ_CONTAINER_NAME = 2, /* subject is a container name pointer */ nr__key_ace_subject_type }; diff --git a/kernel/container.c b/kernel/container.c index 81be4ed915c2..c164c16328d6 100644 --- a/kernel/container.c +++ b/kernel/container.c @@ -235,6 +235,30 @@ struct container *fd_to_container(int fd) return c; } +/** + * find_container - Find a child container by name. + * @name: The name of the container to find. + * + * Find a child of the current container by name. + */ +struct container *find_container(const char *name) +{ + struct container *c = current->container, *p; + + spin_lock(&c->lock); + list_for_each_entry(p, &c->children, child_link) { + if (strcmp(p->name, name) == 0) { + get_container(p); + goto found; + } + } + + p = NULL; +found: + spin_unlock(&c->lock); + return p; +} + /* * Handle fork/clone. * diff --git a/security/keys/compat.c b/security/keys/compat.c index 953156f94320..78c6c0e0eb59 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -175,6 +175,10 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option, case KEYCTL_MOVE: return keyctl_keyring_move(arg2, arg3, arg4, arg5); case KEYCTL_GRANT_PERMISSION: + if (arg3 == KEY_ACE_SUBJ_CONTAINER_NAME) + return keyctl_grant_permission(arg2, arg3, + (unsigned long)compat_ptr(arg4), + arg5); return keyctl_grant_permission(arg2, arg3, arg4, arg5); default: diff --git a/security/keys/internal.h b/security/keys/internal.h index 6cd7b5c17298..aa4ad9c8002e 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -379,7 +379,7 @@ extern long keyctl_set_container_keyring(int, key_serial_t); extern long keyctl_grant_permission(key_serial_t keyid, enum key_ace_subject_type type, - unsigned int subject, + unsigned long subject, unsigned int perm); /* diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 02bd73d5a05a..978c9008c3b2 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1964,7 +1964,7 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, case KEYCTL_GRANT_PERMISSION: return keyctl_grant_permission((key_serial_t)arg2, (enum key_ace_subject_type)arg3, - (unsigned int)arg4, + (unsigned long)arg4, (unsigned int)arg5); default: diff --git a/security/keys/permission.c b/security/keys/permission.c index f16d1665885f..b0e94ccc4635 100644 --- a/security/keys/permission.c +++ b/security/keys/permission.c @@ -407,7 +407,7 @@ static long key_change_acl(struct key *key, struct key_ace *new_ace) */ long keyctl_grant_permission(key_serial_t keyid, enum key_ace_subject_type type, - unsigned int subject, + unsigned long subject, unsigned int perm) { struct key_ace new_ace; @@ -436,6 +436,23 @@ long keyctl_grant_permission(key_serial_t keyid, put_container(c); break; } + case KEY_ACE_SUBJ_CONTAINER_NAME: { + struct container *c; + char *name; + + name = strndup_user((const char __user *)subject, 23); + if (IS_ERR(name)) + return PTR_ERR(name); + c = find_container(name); + kfree(name); + if (!c) + return -EINVAL; + new_ace.type = KEY_ACE_SUBJ_CONTAINER; + refcount_inc(&c->tag->usage); + new_ace.container_tag = c->tag; + put_container(c); + break; + } #endif default: