diff options
Diffstat (limited to 'lib/libcasper/services/cap_fileargs/cap_fileargs.c')
| -rw-r--r-- | lib/libcasper/services/cap_fileargs/cap_fileargs.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/lib/libcasper/services/cap_fileargs/cap_fileargs.c b/lib/libcasper/services/cap_fileargs/cap_fileargs.c new file mode 100644 index 000000000000..2dce6679ee88 --- /dev/null +++ b/lib/libcasper/services/cap_fileargs/cap_fileargs.c @@ -0,0 +1,505 @@ +/*- + * SPDX-License-Identifier: BSD-2-Clause-FreeBSD + * + * Copyright (c) 2018 Mariusz Zaborski <oshogbo@FreeBSD.org> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/types.h> +#include <sys/capsicum.h> +#include <sys/sysctl.h> +#include <sys/cnv.h> +#include <sys/dnv.h> +#include <sys/nv.h> + +#include <assert.h> +#include <errno.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#include <libcasper.h> +#include <libcasper_service.h> + +#include "cap_fileargs.h" + +#define CACHE_SIZE 128 + +#define FILEARGS_MAGIC 0xFA00FA00 + +struct fileargs { + uint32_t fa_magic; + nvlist_t *fa_cache; + cap_channel_t *fa_chann; + int fa_fdflags; +}; + +static int +fileargs_get_cache(fileargs_t *fa, const char *name) +{ + int fd; + const nvlist_t *nvl; + nvlist_t *tnvl; + + assert(fa != NULL); + assert(fa->fa_magic == FILEARGS_MAGIC); + assert(name != NULL); + + if (fa->fa_cache == NULL) + return (-1); + + if ((fa->fa_fdflags & O_CREAT) != 0) + return (-1); + + nvl = dnvlist_get_nvlist(fa->fa_cache, name, NULL); + if (nvl == NULL) + return (-1); + + tnvl = nvlist_take_nvlist(fa->fa_cache, name); + fd = nvlist_take_descriptor(tnvl, "fd"); + nvlist_destroy(tnvl); + + if ((fa->fa_fdflags & O_CLOEXEC) != O_CLOEXEC) { + if (fcntl(fd, F_SETFD, fa->fa_fdflags) == -1) { + close(fd); + return (-1); + } + } + + return (fd); +} + +static void +fileargs_set_cache(fileargs_t *fa, nvlist_t *nvl) +{ + + nvlist_destroy(fa->fa_cache); + fa->fa_cache = nvl; +} + +static nvlist_t* +fileargs_fetch(fileargs_t *fa, const char *name) +{ + nvlist_t *nvl; + int serrno; + + assert(fa != NULL); + assert(name != NULL); + + nvl = nvlist_create(NV_FLAG_NO_UNIQUE); + nvlist_add_string(nvl, "cmd", "open"); + nvlist_add_string(nvl, "name", name); + + nvl = cap_xfer_nvlist(fa->fa_chann, nvl); + if (nvl == NULL) + return (NULL); + + if (nvlist_get_number(nvl, "error") != 0) { + serrno = (int)nvlist_get_number(nvl, "error"); + nvlist_destroy(nvl); + errno = serrno; + return (NULL); + } + + return (nvl); +} + +static nvlist_t * +fileargs_create_limit(int argc, const char * const *argv, int flags, + mode_t mode, cap_rights_t *rightsp) +{ + nvlist_t *limits; + int i; + + limits = nvlist_create(NV_FLAG_NO_UNIQUE); + if (limits == NULL) + return (NULL); + + nvlist_add_number(limits, "flags", flags); + if (rightsp != NULL) { + nvlist_add_binary(limits, "cap_rights", rightsp, + sizeof(*rightsp)); + } + if ((flags & O_CREAT) != 0) + nvlist_add_number(limits, "mode", (uint64_t)mode); + + for (i = 0; i < argc; i++) { + nvlist_add_null(limits, argv[i]); + } + + return (limits); +} + +static fileargs_t * +fileargs_create(cap_channel_t *chan, int fdflags) +{ + fileargs_t *fa; + + fa = malloc(sizeof(*fa)); + if (fa != NULL) { + fa->fa_cache = NULL; + fa->fa_chann = chan; + fa->fa_fdflags = fdflags; + fa->fa_magic = FILEARGS_MAGIC; + } + + return (fa); +} + +fileargs_t * +fileargs_init(int argc, char *argv[], int flags, mode_t mode, + cap_rights_t *rightsp) +{ + nvlist_t *limits; + + if (argv <= 0 || argv == NULL) { + return (fileargs_create(NULL, 0)); + } + + limits = fileargs_create_limit(argc, (const char * const *)argv, flags, + mode, rightsp); + if (limits == NULL) + return (NULL); + + return (fileargs_initnv(limits)); +} + +fileargs_t * +fileargs_cinit(cap_channel_t *cas, int argc, char *argv[], int flags, + mode_t mode, cap_rights_t *rightsp) +{ + nvlist_t *limits; + + if (argv <= 0 || argv == NULL) { + return (fileargs_create(NULL, 0)); + } + + limits = fileargs_create_limit(argc, (const char * const *)argv, flags, + mode, rightsp); + if (limits == NULL) + return (NULL); + + return (fileargs_cinitnv(cas, limits)); +} + +fileargs_t * +fileargs_initnv(nvlist_t *limits) +{ + cap_channel_t *cas; + fileargs_t *fa; + + if (limits == NULL) { + return (fileargs_create(NULL, 0)); + } + + cas = cap_init(); + if (cas == NULL) { + nvlist_destroy(limits); + return (NULL); + } + + fa = fileargs_cinitnv(cas, limits); + cap_close(cas); + + return (fa); +} + +fileargs_t * +fileargs_cinitnv(cap_channel_t *cas, nvlist_t *limits) +{ + cap_channel_t *chann; + fileargs_t *fa; + int serrno, ret; + int flags; + + assert(cas != NULL); + + if (limits == NULL) { + return (fileargs_create(NULL, 0)); + } + + chann = NULL; + fa = NULL; + + chann = cap_service_open(cas, "system.fileargs"); + if (chann == NULL) { + nvlist_destroy(limits); + return (NULL); + } + + flags = nvlist_get_number(limits, "flags"); + + /* Limits are consumed no need to free them. */ + ret = cap_limit_set(chann, limits); + if (ret < 0) + goto out; + + fa = fileargs_create(chann, flags); + if (fa == NULL) + goto out; + + return (fa); +out: + serrno = errno; + if (chann != NULL) + cap_close(chann); + errno = serrno; + return (NULL); +} + +int +fileargs_open(fileargs_t *fa, const char *name) +{ + int fd; + nvlist_t *nvl; + char *cmd; + + assert(fa != NULL); + assert(fa->fa_magic == FILEARGS_MAGIC); + + if (name == NULL) { + errno = EINVAL; + return (-1); + } + + if (fa->fa_chann == NULL) { + errno = ENOTCAPABLE; + return (-1); + } + + fd = fileargs_get_cache(fa, name); + if (fd != -1) + return (fd); + + nvl = fileargs_fetch(fa, name); + if (nvl == NULL) + return (-1); + + fd = nvlist_take_descriptor(nvl, "fd"); + cmd = nvlist_take_string(nvl, "cmd"); + if (strcmp(cmd, "cache") == 0) + fileargs_set_cache(fa, nvl); + else + nvlist_destroy(nvl); + free(cmd); + + return (fd); +} + +FILE * +fileargs_fopen(fileargs_t *fa, const char *name, const char *mode) +{ + int fd; + + if ((fd = fileargs_open(fa, name)) < 0) { + return (NULL); + } + + return (fdopen(fd, mode)); +} + +void +fileargs_free(fileargs_t *fa) +{ + + if (fa == NULL) + return; + + assert(fa->fa_magic == FILEARGS_MAGIC); + + nvlist_destroy(fa->fa_cache); + if (fa->fa_chann != NULL) { + cap_close(fa->fa_chann); + } + explicit_bzero(&fa->fa_magic, sizeof(fa->fa_magic)); + free(fa); +} + +/* + * Service functions. + */ + +static const char *lastname; +static void *cacheposition; +static bool allcached; +static const cap_rights_t *caprightsp; +static int capflags; +static mode_t capmode; + +static int +open_file(const char *name) +{ + int fd, serrno; + + if ((capflags & O_CREAT) == 0) + fd = open(name, capflags); + else + fd = open(name, capflags, capmode); + if (fd < 0) + return (-1); + + if (caprightsp != NULL) { + if (cap_rights_limit(fd, caprightsp) < 0) { + serrno = errno; + close(fd); + errno = serrno; + return (-1); + } + } + + return (fd); +} + +static void +fileargs_add_cache(nvlist_t *nvlout, const nvlist_t *limits, + const char *curent_name) +{ + int type, i, fd; + void *cookie; + nvlist_t *new; + const char *fname; + + if ((capflags & O_CREAT) != 0) { + allcached = true; + return; + } + + cookie = cacheposition; + for (i = 0; i < CACHE_SIZE + 1; i++) { + fname = nvlist_next(limits, &type, &cookie); + if (fname == NULL) { + cacheposition = NULL; + lastname = NULL; + allcached = true; + return; + } + /* We doing that to catch next element name. */ + if (i == CACHE_SIZE) { + break; + } + + if (type != NV_TYPE_NULL || + (curent_name != NULL && strcmp(fname, curent_name) == 0)) { + curent_name = NULL; + i--; + continue; + } + + fd = open_file(fname); + if (fd < 0) { + i--; + continue; + } + + new = nvlist_create(NV_FLAG_NO_UNIQUE); + nvlist_move_descriptor(new, "fd", fd); + nvlist_add_nvlist(nvlout, fname, new); + } + cacheposition = cookie; + lastname = fname; +} + +static bool +fileargs_allowed(const nvlist_t *limits, const nvlist_t *request) +{ + const char *name; + + name = dnvlist_get_string(request, "name", NULL); + if (name == NULL) + return (false); + + /* Fast path. */ + if (lastname != NULL && strcmp(name, lastname) == 0) + return (true); + + if (!nvlist_exists_null(limits, name)) + return (false); + + return (true); +} + +static int +fileargs_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits) +{ + + if (oldlimits != NULL) + return (ENOTCAPABLE); + + capflags = (int)dnvlist_get_number(newlimits, "flags", 0); + if ((capflags & O_CREAT) != 0) + capmode = (mode_t)nvlist_get_number(newlimits, "mode"); + else + capmode = 0; + + caprightsp = dnvlist_get_binary(newlimits, "cap_rights", NULL, NULL, 0); + + return (0); +} + +static int +fileargs_command_open(const nvlist_t *limits, nvlist_t *nvlin, + nvlist_t *nvlout) +{ + int fd; + const char *name; + + if (limits == NULL) + return (ENOTCAPABLE); + + if (!fileargs_allowed(limits, nvlin)) + return (ENOTCAPABLE); + + name = nvlist_get_string(nvlin, "name"); + + fd = open_file(name); + if (fd < 0) + return (errno); + + if (!allcached && (lastname == NULL || + strcmp(name, lastname) == 0)) { + nvlist_add_string(nvlout, "cmd", "cache"); + fileargs_add_cache(nvlout, limits, name); + } else { + nvlist_add_string(nvlout, "cmd", "open"); + } + nvlist_move_descriptor(nvlout, "fd", fd); + return (0); +} + +static int +fileargs_command(const char *cmd, const nvlist_t *limits, + nvlist_t *nvlin, nvlist_t *nvlout) +{ + + if (strcmp(cmd, "open") == 0) + return (fileargs_command_open(limits, nvlin, nvlout)); + + return (EINVAL); +} + +CREATE_SERVICE("system.fileargs", fileargs_limit, fileargs_command, + CASPER_SERVICE_FD | CASPER_SERVICE_STDIO | CASPER_SERVICE_NO_UNIQ_LIMITS); |