diff options
Diffstat (limited to 'libexec/casper/sysctl/sysctl.c')
| -rw-r--r-- | libexec/casper/sysctl/sysctl.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/libexec/casper/sysctl/sysctl.c b/libexec/casper/sysctl/sysctl.c new file mode 100644 index 0000000..4cbc505 --- /dev/null +++ b/libexec/casper/sysctl/sysctl.c @@ -0,0 +1,249 @@ +/*- + * Copyright (c) 2013 The FreeBSD Foundation + * All rights reserved. + * + * This software was developed by Pawel Jakub Dawidek under sponsorship from + * the FreeBSD Foundation. + * + * 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/sysctl.h> +#include <sys/nv.h> + +#include <errno.h> +#include <stdlib.h> +#include <string.h> + +#include <libcapsicum.h> +#include <libcapsicum_sysctl.h> +#include <libcasper.h> +#include <pjdlog.h> + +static int +sysctl_check_one(const nvlist_t *nvl, bool islimit) +{ + const char *name; + void *cookie; + int type; + unsigned int fields; + + /* NULL nvl is of course invalid. */ + if (nvl == NULL) + return (EINVAL); + if (nvlist_error(nvl) != 0) + return (nvlist_error(nvl)); + +#define HAS_NAME 0x01 +#define HAS_OPERATION 0x02 + + fields = 0; + cookie = NULL; + while ((name = nvlist_next(nvl, &type, &cookie)) != NULL) { + /* We accept only one 'name' and one 'operation' in nvl. */ + if (strcmp(name, "name") == 0) { + if (type != NV_TYPE_STRING) + return (EINVAL); + /* Only one 'name' can be present. */ + if ((fields & HAS_NAME) != 0) + return (EINVAL); + fields |= HAS_NAME; + } else if (strcmp(name, "operation") == 0) { + uint64_t operation; + + if (type != NV_TYPE_NUMBER) + return (EINVAL); + /* + * We accept only CAP_SYSCTL_READ and + * CAP_SYSCTL_WRITE flags. + */ + operation = nvlist_get_number(nvl, name); + if ((operation & ~(CAP_SYSCTL_RDWR)) != 0) + return (EINVAL); + /* ...but there has to be at least one of them. */ + if ((operation & (CAP_SYSCTL_RDWR)) == 0) + return (EINVAL); + /* Only one 'operation' can be present. */ + if ((fields & HAS_OPERATION) != 0) + return (EINVAL); + fields |= HAS_OPERATION; + } else if (islimit) { + /* If this is limit, there can be no other fields. */ + return (EINVAL); + } + } + + /* Both fields has to be there. */ + if (fields != (HAS_NAME | HAS_OPERATION)) + return (EINVAL); + +#undef HAS_OPERATION +#undef HAS_NAME + + return (0); +} + +static bool +sysctl_allowed(const nvlist_t *limits, const char *chname, uint64_t choperation) +{ + uint64_t operation; + const char *name; + void *cookie; + int type; + + if (limits == NULL) + return (true); + + cookie = NULL; + while ((name = nvlist_next(limits, &type, &cookie)) != NULL) { + PJDLOG_ASSERT(type == NV_TYPE_NUMBER); + + operation = nvlist_get_number(limits, name); + if ((operation & choperation) != choperation) + continue; + + if ((operation & CAP_SYSCTL_RECURSIVE) == 0) { + if (strcmp(name, chname) != 0) + continue; + } else { + size_t namelen; + + namelen = strlen(name); + if (strncmp(name, chname, namelen) != 0) + continue; + if (chname[namelen] != '.' && chname[namelen] != '\0') + continue; + } + + return (true); + } + + return (false); +} + +static int +sysctl_limit(const nvlist_t *oldlimits, const nvlist_t *newlimits) +{ + const nvlist_t *nvl; + const char *name; + void *cookie; + uint64_t operation; + int error, type; + + cookie = NULL; + while ((name = nvlist_next(newlimits, &type, &cookie)) != NULL) { + if (type != NV_TYPE_NUMBER) + return (EINVAL); + operation = nvlist_get_number(newlimits, name); + if ((operation & ~(CAP_SYSCTL_RDWR | CAP_SYSCTL_RECURSIVE)) != 0) + return (EINVAL); + if ((operation & (CAP_SYSCTL_RDWR | CAP_SYSCTL_RECURSIVE)) == 0) + return (EINVAL); + if (!sysctl_allowed(oldlimits, name, operation)) + return (ENOTCAPABLE); + } + + return (0); +} + +static int +sysctl_command(const char *cmd, const nvlist_t *limits, nvlist_t *nvlin, + nvlist_t *nvlout) +{ + const char *name; + const void *newp; + void *oldp; + uint64_t operation; + size_t oldlen, newlen; + size_t *oldlenp; + int error; + + if (strcmp(cmd, "sysctl") != 0) + return (EINVAL); + error = sysctl_check_one(nvlin, false); + if (error != 0) + return (error); + + name = nvlist_get_string(nvlin, "name"); + operation = nvlist_get_number(nvlin, "operation"); + if (!sysctl_allowed(limits, name, operation)) + return (ENOTCAPABLE); + + if ((operation & CAP_SYSCTL_WRITE) != 0) { + if (!nvlist_exists_binary(nvlin, "newp")) + return (EINVAL); + newp = nvlist_get_binary(nvlin, "newp", &newlen); + PJDLOG_ASSERT(newp != NULL && newlen > 0); + } else { + newp = NULL; + newlen = 0; + } + + if ((operation & CAP_SYSCTL_READ) != 0) { + if (nvlist_exists_null(nvlin, "justsize")) { + oldp = NULL; + oldlen = 0; + oldlenp = &oldlen; + } else { + if (!nvlist_exists_number(nvlin, "oldlen")) + return (EINVAL); + oldlen = (size_t)nvlist_get_number(nvlin, "oldlen"); + if (oldlen == 0) + return (EINVAL); + oldp = calloc(1, oldlen); + if (oldp == NULL) + return (ENOMEM); + oldlenp = &oldlen; + } + } else { + oldp = NULL; + oldlen = 0; + oldlenp = NULL; + } + + if (sysctlbyname(name, oldp, oldlenp, newp, newlen) == -1) { + error = errno; + free(oldp); + return (error); + } + + if ((operation & CAP_SYSCTL_READ) != 0) { + if (nvlist_exists_null(nvlin, "justsize")) + nvlist_add_number(nvlout, "oldlen", (uint64_t)oldlen); + else + nvlist_move_binary(nvlout, "oldp", oldp, oldlen); + } + + return (0); +} + +int +main(int argc, char *argv[]) +{ + + return (service_start("system.sysctl", PARENT_FILENO, sysctl_limit, + sysctl_command, argc, argv)); +} |
