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Registered in England and Wales under Company Registration No. 3798903 Subject: [RFC PATCH 19/27] containers: Sample: request_key upcall handling 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 16:10:30 +0000 Message-ID: <155024703003.21651.3499235528404179500.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 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Fri, 15 Feb 2019 16:10:40 +0000 (UTC) Sender: linux-nfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-nfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Implement a sample upcall handling. Firstly, the test-container sample is modified to (a) create a staging keyring and to (b) intercept request_key calls for user-type keys inside the container and place the authentication keys into that rather than invoking /sbin/request-key. Secondly, a test-upcall sample is added that will monitor the keyring for notifications and spawn /sbin/request-key instances for each of key added. This is run as: ./test-upcall to find a keyring called "upcall" in the session keyring (as created by the ./test-container program) and listen for additions to that, or it can be run as: ./test-upcall to listen on a specific keyring. Note that the test-upcall sample is designed to be run separately from test-container so that its stdout can be observed. Signed-off-by: David Howells --- samples/vfs/Makefile | 6 + samples/vfs/test-container.c | 16 +++ samples/vfs/test-upcall.c | 243 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 264 insertions(+), 1 deletion(-) create mode 100644 samples/vfs/test-upcall.c diff --git a/samples/vfs/Makefile b/samples/vfs/Makefile index 25420919ee40..a8e9e1142ae3 100644 --- a/samples/vfs/Makefile +++ b/samples/vfs/Makefile @@ -5,7 +5,8 @@ hostprogs-$(CONFIG_SAMPLE_VFS) := \ test-fsmount \ test-mntinfo \ test-statx \ - test-container + test-container \ + test-upcall # Tell kbuild to always build the programs always := $(hostprogs-y) @@ -18,5 +19,8 @@ HOSTLDLIBS_test-mntinfo += -lm HOSTCFLAGS_test-fs-query.o += -I$(objtree)/usr/include HOSTCFLAGS_test-fsmount.o += -I$(objtree)/usr/include HOSTCFLAGS_test-statx.o += -I$(objtree)/usr/include + HOSTCFLAGS_test-container.o += -I$(objtree)/usr/include HOSTLDLIBS_test-container += -lkeyutils +HOSTCFLAGS_test-upcall.o += -I$(objtree)/usr/include +HOSTLDLIBS_test-upcall += -lkeyutils diff --git a/samples/vfs/test-container.c b/samples/vfs/test-container.c index 44ff57afb5a4..7dc9071399b2 100644 --- a/samples/vfs/test-container.c +++ b/samples/vfs/test-container.c @@ -20,6 +20,8 @@ #include #include +#define KEYCTL_CONTAINER_INTERCEPT 31 /* Intercept upcalls inside a container */ + /* Hope -1 isn't a syscall */ #ifndef __NR_fsopen #define __NR_fsopen -1 @@ -187,6 +189,7 @@ void container_init(void) */ int main(int argc, char *argv[]) { + key_serial_t keyring; pid_t pid; int fsfd, mfd, cfd, ws; @@ -259,6 +262,19 @@ int main(int argc, char *argv[]) E(close(fsfd)); E(close(mfd)); + /* Create a keyring to catch upcalls. */ + printf("Intercepting...\n"); + keyring = add_key("keyring", "upcall", NULL, 0, KEY_SPEC_SESSION_KEYRING); + if (keyring == -1) { + perror("add_key/u"); + exit(1); + } + + if (keyctl(KEYCTL_CONTAINER_INTERCEPT, cfd, "user", 0, keyring) < 0) { + perror("keyctl_container_intercept"); + exit(1); + } + /* Start the 'init' process. */ printf("Forking...\n"); switch ((pid = fork_into_container(cfd))) { diff --git a/samples/vfs/test-upcall.c b/samples/vfs/test-upcall.c new file mode 100644 index 000000000000..225fa0325d1b --- /dev/null +++ b/samples/vfs/test-upcall.c @@ -0,0 +1,243 @@ +/* Container keyring upcall management test. + * + * Copyright (C) 2019 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public Licence + * as published by the Free Software Foundation; either version + * 2 of the Licence, or (at your option) any later version. + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define KEYCTL_WATCH_KEY 30 /* Watch a key or ring of keys for changes */ +#define KEYCTL_QUERY_REQUEST_KEY_AUTH 32 /* Query a request_key_auth key */ +#define KEYCTL_MOVE 33 /* Move keys between keyrings */ +#define KEYCTL_FIND_LRU 34 /* Find the least-recently used key in a keyring */ + +struct keyctl_query_request_key_auth { + char operation[32]; /* Operation name, typically "create" */ + uid_t fsuid; /* UID of requester */ + gid_t fsgid; /* GID of requester */ + key_serial_t target_key; /* The key being instantiated */ + key_serial_t thread_keyring; /* The requester's thread keyring */ + key_serial_t process_keyring; /* The requester's process keyring */ + key_serial_t session_keyring; /* The requester's session keyring */ + long long spare[1]; +}; + +static void process_request(key_serial_t keyring, key_serial_t key) +{ + struct keyctl_query_request_key_auth info; + char target[32], uid[32], gid[32], thread[32], process[32], session[32]; + void *callout; + long len; + +#if 0 + key = keyctl(KEYCTL_FIND_LRU, keyring, ".request_key_auth"); + if (key == -1) { + perror("keyctl/find"); + exit(1); + } +#endif + + if (keyctl(KEYCTL_QUERY_REQUEST_KEY_AUTH, key, &info) == -1) { + perror("keyctl/query"); + exit(1); + } + + len = keyctl_read_alloc(key, &callout); + if (len == -1) { + perror("keyctl/read"); + exit(1); + } + + sprintf(target, "%d", info.target_key); + sprintf(uid, "%d", info.fsuid); + sprintf(gid, "%d", info.fsgid); + sprintf(thread, "%d", info.thread_keyring); + sprintf(process, "%d", info.process_keyring); + sprintf(session, "%d", info.session_keyring); + + printf("Authentication key %d\n", key); + printf("- %s %s\n", info.operation, target); + printf("- uid=%s gid=%s\n", uid, gid); + printf("- rings=%s,%s,%s\n", thread, process, session); + printf("- callout='%s'\n", (char *)callout); + + switch (fork()) { + case 0: + /* Only pass the auth token of interest onto /sbin/request-key */ + if (keyctl(KEYCTL_MOVE, key, keyring, KEY_SPEC_THREAD_KEYRING) < 0) { + perror("keyctl_move/1"); + exit(1); + } + + if (keyctl_join_session_keyring(NULL) < 0) { + perror("keyctl_join"); + exit(1); + } + + if (keyctl(KEYCTL_MOVE, key, + KEY_SPEC_THREAD_KEYRING, KEY_SPEC_SESSION_KEYRING) < 0) { + perror("keyctl_move/2"); + exit(1); + } + + execl("/sbin/request-key", + "request-key", info.operation, target, uid, gid, thread, process, session, + NULL); + perror("execve"); + exit(1); + + case -1: + perror("fork"); + exit(1); + + default: + return; + } +} + +/* + * We saw a change on the keyring. + */ +static void saw_key_change(struct watch_notification *n) +{ + struct key_notification *k = (struct key_notification *)n; + unsigned int len = n->info & WATCH_INFO_LENGTH; + + if (len != sizeof(struct key_notification)) + return; + + printf("KEY %d change=%u aux=%d\n", k->key_id, n->subtype, k->aux); + + process_request(k->key_id, k->aux); +} + +/* + * Consume and display events. + */ +static int consumer(int fd, struct watch_queue_buffer *buf) +{ + struct watch_notification *n; + struct pollfd p[1]; + unsigned int head, tail, mask = buf->meta.mask; + + for (;;) { + p[0].fd = fd; + p[0].events = POLLIN | POLLERR; + p[0].revents = 0; + + if (poll(p, 1, -1) == -1) { + perror("poll"); + break; + } + + printf("ptrs h=%x t=%x m=%x\n", + buf->meta.head, buf->meta.tail, buf->meta.mask); + + while (head = __atomic_load_n(&buf->meta.head, __ATOMIC_ACQUIRE), + tail = buf->meta.tail, + tail != head + ) { + n = &buf->slots[tail & mask]; + printf("NOTIFY[%08x-%08x] ty=%04x sy=%04x i=%08x\n", + head, tail, n->type, n->subtype, n->info); + if ((n->info & WATCH_INFO_LENGTH) == 0) + goto out; + + switch (n->type) { + case WATCH_TYPE_META: + if (n->subtype == WATCH_META_REMOVAL_NOTIFICATION) + printf("REMOVAL of watchpoint %08x\n", + n->info & WATCH_INFO_ID); + break; + case WATCH_TYPE_KEY_NOTIFY: + saw_key_change(n); + break; + } + + tail += (n->info & WATCH_INFO_LENGTH) >> WATCH_LENGTH_SHIFT; + __atomic_store_n(&buf->meta.tail, tail, __ATOMIC_RELEASE); + } + } + +out: + return 0; +} + +/* + * We're only interested in key insertion events. + */ +static struct watch_notification_filter filter = { + .nr_filters = 1, + .filters = { + [0] = { + .type = WATCH_TYPE_KEY_NOTIFY, + .subtype_filter[0] = (1 << NOTIFY_KEY_LINKED), + }, + } +}; + +int main(int argc, char *argv[]) +{ + struct watch_queue_buffer *buf; + key_serial_t keyring; + size_t page_size = sysconf(_SC_PAGESIZE); + int fd; + + if (argc == 1) { + keyring = keyctl_search(KEY_SPEC_SESSION_KEYRING, "keyring", + "upcall", 0); + if (keyring == -1) { + perror("keyctl_search"); + exit(1); + } + } else if (argc == 2) { + keyring = strtoul(argv[1], NULL, 0); + } else { + fprintf(stderr, "Format: test-upcall []\n"); + exit(2); + } + + /* Create a watch on the keyring to detect the addition of keys. */ + fd = open("/dev/watch_queue", O_RDWR | O_CLOEXEC); + if (fd == -1) { + perror("/dev/watch_queue"); + exit(1); + } + + if (ioctl(fd, IOC_WATCH_QUEUE_SET_SIZE, 1) == -1) { + perror("/dev/watch_queue(size)"); + exit(1); + } + + if (ioctl(fd, IOC_WATCH_QUEUE_SET_FILTER, &filter) == -1) { + perror("/dev/watch_queue(filter)"); + exit(1); + } + + buf = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (buf == MAP_FAILED) { + perror("mmap"); + exit(1); + } + + if (keyctl(KEYCTL_WATCH_KEY, keyring, fd, 0x01) == -1) { + perror("keyctl"); + exit(1); + } + + return consumer(fd, buf); +}