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lib/libsecureboot/verify_file.c
- This file was added.
| Property | Old Value | New Value |
|---|---|---|
| svn:eol-style | null | native \ No newline at end of property |
| svn:keywords | null | FreeBSD=%H \ No newline at end of property |
| svn:mime-type | null | text/plain \ No newline at end of property |
| /*- | |||||
| * Copyright (c) 2017-2018, Juniper Networks, Inc. | |||||
| * | |||||
| * 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 COPYRIGHT HOLDERS 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 COPYRIGHT | |||||
| * OWNER 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. | |||||
| */ | |||||
| /* | |||||
| * Routines to verify files loaded. | |||||
| */ | |||||
| #include <sys/cdefs.h> | |||||
| __FBSDID("$FreeBSD$"); | |||||
| #include <sys/param.h> | |||||
| #include <string.h> | |||||
| #include <sys/queue.h> | |||||
| #include "libsecureboot.h" | |||||
| #include <verify_file.h> | |||||
| #include <manifests.h> | |||||
| #define VE_NOT_CHECKED -42 | |||||
| #ifdef UNIT_TEST | |||||
| # include <err.h> | |||||
| # define panic warn | |||||
| /* | |||||
| * define MANIFEST_SKIP to Skip - in tests/tvo.c so that | |||||
| * tvo can control the value we use in find_manifest() | |||||
| */ | |||||
| extern char *Skip; | |||||
| # undef MANIFEST_SKIP | |||||
| # define MANIFEST_SKIP Skip | |||||
| # undef VE_DEBUG_LEVEL | |||||
| #endif | |||||
| /* | |||||
| * We sometimes need to know if input is verified or not. | |||||
| * The extra slot is for tracking most recently opened. | |||||
| */ | |||||
| static int ve_status[SOPEN_MAX+1]; | |||||
| static int ve_status_state; | |||||
| struct verify_status; | |||||
| struct verify_status *verified_files = NULL; | |||||
| static int loaded_manifests = 0; /* have we loaded anything? */ | |||||
| #define VE_STATUS_NONE 1 | |||||
| #define VE_STATUS_VALID 2 | |||||
| /** | |||||
| * @brief set ve status for fd | |||||
| */ | |||||
| static void | |||||
| ve_status_set(int fd, int ves) | |||||
| { | |||||
| if (fd >= 0 && fd < SOPEN_MAX) { | |||||
| ve_status[fd] = ves; | |||||
| ve_status_state = VE_STATUS_VALID; | |||||
| } | |||||
| ve_status[SOPEN_MAX] = ves; | |||||
| } | |||||
| /** | |||||
| * @brief get ve status of fd | |||||
| * | |||||
| * What we return depends on ve_status_state. | |||||
| * | |||||
| * @return | |||||
| * @li ve_status[fd] if ve_status_state is valid | |||||
| * @li ve_status[SOPEN_MAX] if ve_status_state is none | |||||
| * @li VE_NOT_CHECKED if ve_status_state uninitialized | |||||
| */ | |||||
| int | |||||
| ve_status_get(int fd) | |||||
| { | |||||
| if (!ve_status_state) { | |||||
| return (VE_NOT_CHECKED); | |||||
| } | |||||
| if (ve_status_state == VE_STATUS_VALID && | |||||
| fd >= 0 && fd < SOPEN_MAX) | |||||
| return (ve_status[fd]); | |||||
| return (ve_status[SOPEN_MAX]); /* most recent */ | |||||
| } | |||||
| /** | |||||
| * @brief track verify status | |||||
| * | |||||
| * occasionally loader will make multiple calls | |||||
| * for the same file, we need only check it once. | |||||
| */ | |||||
| struct verify_status { | |||||
| dev_t vs_dev; | |||||
| ino_t vs_ino; | |||||
| int vs_status; | |||||
| struct verify_status *vs_next; | |||||
| }; | |||||
| static int | |||||
| is_verified(struct stat *stp) | |||||
| { | |||||
| struct verify_status *vsp; | |||||
| for (vsp = verified_files; vsp != NULL; vsp = vsp->vs_next) { | |||||
| if (stp->st_dev == vsp->vs_dev && | |||||
| stp->st_ino == vsp->vs_ino) | |||||
| return (vsp->vs_status); | |||||
| } | |||||
| return (VE_NOT_CHECKED); | |||||
| } | |||||
| /* most recent first, since most likely to see repeated calls. */ | |||||
| static void | |||||
| add_verify_status(struct stat *stp, int status) | |||||
| { | |||||
| struct verify_status *vsp; | |||||
| vsp = malloc(sizeof(struct verify_status)); | |||||
| vsp->vs_next = verified_files; | |||||
| vsp->vs_dev = stp->st_dev; | |||||
| vsp->vs_ino = stp->st_ino; | |||||
| vsp->vs_status = status; | |||||
| verified_files = vsp; | |||||
| } | |||||
| /** | |||||
| * @brief | |||||
| * load specified manifest if verified | |||||
| */ | |||||
| int | |||||
| load_manifest(const char *name, const char *prefix, | |||||
| const char *skip, struct stat *stp) | |||||
| { | |||||
| struct stat st; | |||||
| size_t n; | |||||
| int rc; | |||||
| char *content; | |||||
| rc = VE_FINGERPRINT_NONE; | |||||
| n = strlen(name); | |||||
| if (n > 4) { | |||||
| if (!stp) { | |||||
| stp = &st; | |||||
| if (stat(name, &st) < 0 || !S_ISREG(st.st_mode)) | |||||
| return (rc); | |||||
| } | |||||
| rc = is_verified(stp); | |||||
| if (rc != VE_NOT_CHECKED) { | |||||
| return (rc); | |||||
| } | |||||
| /* loader has no sense of time */ | |||||
| ve_utc_set(stp->st_mtime); | |||||
| content = (char *)verify_signed(name, VEF_VERBOSE); | |||||
| if (content) { | |||||
| fingerprint_info_add(name, prefix, skip, content, stp); | |||||
| add_verify_status(stp, VE_VERIFIED); | |||||
| loaded_manifests = 1; /* we are verifying! */ | |||||
| DEBUG_PRINTF(3, ("loaded: %s %s %s\n", | |||||
| name, prefix, skip)); | |||||
| rc = 0; | |||||
| } else { | |||||
| rc = VE_FINGERPRINT_WRONG; | |||||
| add_verify_status(stp, rc); /* remember */ | |||||
| } | |||||
| } | |||||
| return (rc); | |||||
| } | |||||
| static int | |||||
| find_manifest(const char *name) | |||||
| { | |||||
| struct stat st; | |||||
| char buf[MAXPATHLEN]; | |||||
| char *prefix; | |||||
| char *skip; | |||||
| const char **tp; | |||||
| int rc; | |||||
| strncpy(buf, name, MAXPATHLEN - 1); | |||||
| if (!(prefix = strrchr(buf, '/'))) | |||||
| return (-1); | |||||
| *prefix = '\0'; | |||||
| prefix = strdup(buf); | |||||
| rc = VE_FINGERPRINT_NONE; | |||||
| for (tp = manifest_names; *tp; tp++) { | |||||
| snprintf(buf, sizeof(buf), "%s/%s", prefix, *tp); | |||||
| DEBUG_PRINTF(5, ("looking for %s\n", buf)); | |||||
| if (stat(buf, &st) == 0 && st.st_size > 0) { | |||||
| #ifdef MANIFEST_SKIP_ALWAYS /* very unlikely */ | |||||
| skip = MANIFEST_SKIP_ALWAYS; | |||||
| #else | |||||
| #ifdef MANIFEST_SKIP /* rare */ | |||||
| if (*tp[0] == '.') { | |||||
| skip = MANIFEST_SKIP; | |||||
| } else | |||||
| #endif | |||||
| skip = NULL; | |||||
| #endif | |||||
| rc = load_manifest(buf, skip ? prefix : NULL, | |||||
| skip, &st); | |||||
| break; | |||||
| } | |||||
| } | |||||
| free(prefix); | |||||
| return (rc); | |||||
| } | |||||
| #ifdef LOADER_VERIEXEC_TESTING | |||||
| # define ACCEPT_NO_FP_DEFAULT VE_MUST + 1 | |||||
| #else | |||||
| # define ACCEPT_NO_FP_DEFAULT VE_MUST | |||||
| #endif | |||||
| #ifndef VE_VERBOSE_DEFAULT | |||||
| # define VE_VERBOSE_DEFAULT 0 | |||||
| #endif | |||||
| static int | |||||
| severity_guess(const char *filename) | |||||
| { | |||||
| const char *cp; | |||||
| /* Some files like *.conf and *.hints may be unsigned */ | |||||
| if ((cp = strrchr(filename, '.'))) { | |||||
| if (strcmp(cp, ".conf") == 0 || | |||||
| strcmp(cp, ".cookie") == 0 || | |||||
| strcmp(cp, ".hints") == 0) | |||||
| return (VE_TRY); | |||||
| } | |||||
| return (VE_WANT); | |||||
| } | |||||
| static void | |||||
| verify_tweak(char *tweak, int *accept_no_fp, int *verbose, int *verifying) | |||||
| { | |||||
| if (strcmp(tweak, "off") == 0) { | |||||
| *verifying = 0; | |||||
| } else if (strcmp(tweak, "strict") == 0) { | |||||
| /* anything caller wants verified must be */ | |||||
| *accept_no_fp = VE_WANT; | |||||
| *verbose = 1; /* warn of anything unverified */ | |||||
| /* treat self test failure as fatal */ | |||||
| if (!ve_self_tests()) { | |||||
| panic("verify self tests failed"); | |||||
| } | |||||
| } else if (strcmp(tweak, "modules") == 0) { | |||||
| /* modules/kernel must be verified */ | |||||
| *accept_no_fp = VE_MUST; | |||||
| } else if (strcmp(tweak, "try") == 0) { | |||||
| /* best effort: always accept no fp */ | |||||
| *accept_no_fp = VE_MUST + 1; | |||||
| } else if (strcmp(tweak, "verbose") == 0) { | |||||
| *verbose = 1; | |||||
| } else if (strcmp(tweak, "quiet") == 0) { | |||||
| *verbose = 0; | |||||
| } | |||||
| } | |||||
| /** | |||||
| * @brief verify an open file | |||||
| * | |||||
| * @param[in] fd | |||||
| * open descriptor | |||||
| * | |||||
| * @param[in] filename | |||||
| * path we opened and will use to lookup fingerprint | |||||
| * | |||||
| * @param[in] off | |||||
| * current offset in fd, must be restored on return | |||||
| * | |||||
| * @param[in] severity | |||||
| * indicator of how to handle case of missing fingerprint | |||||
| * | |||||
| * We look for a signed manifest relative to the filename | |||||
| * just opened and verify/load it if needed. | |||||
| * | |||||
| * We then use verify_fd() in libve to actually verify that hash for | |||||
| * open file. If it returns < 0 we look at the severity arg to decide | |||||
| * what to do about it. | |||||
| * | |||||
| * If verify_fd() returns VE_FINGERPRINT_NONE we accept it if severity | |||||
| * is < accept_no_fp. | |||||
| * | |||||
| * @return >= 0 on success < 0 on failure | |||||
| */ | |||||
| int | |||||
| verify_file(int fd, const char *filename, off_t off, int severity) | |||||
| { | |||||
| static int verifying = -1; | |||||
| static int accept_no_fp = ACCEPT_NO_FP_DEFAULT; | |||||
| static int verbose = VE_VERBOSE_DEFAULT; | |||||
| struct stat st; | |||||
| char *cp; | |||||
| int rc; | |||||
| if (verifying < 0) { | |||||
| verifying = ve_trust_init(); | |||||
| #ifdef VE_DEBUG_LEVEL | |||||
| ve_debug_set(VE_DEBUG_LEVEL); | |||||
| #endif | |||||
| /* initialize ve_status with default result */ | |||||
| rc = verifying ? VE_NOT_CHECKED : VE_NOT_VERIFYING; | |||||
| ve_status_set(0, rc); | |||||
| ve_status_state = VE_STATUS_NONE; | |||||
| if (verifying) | |||||
| ve_self_tests(); | |||||
| } | |||||
| if (!verifying) | |||||
| return (0); | |||||
| if (fd < 0 || fstat(fd, &st) < 0 || !S_ISREG(st.st_mode)) | |||||
| return (0); | |||||
| DEBUG_PRINTF(3, ("fd=%d,name='%s',off=%lld,dev=%lld,ino=%lld\n", | |||||
| fd, filename, (long long)off, st.st_dev,st.st_ino)); | |||||
| rc = is_verified(&st); | |||||
| if (rc != VE_NOT_CHECKED) { | |||||
| ve_status_set(fd, rc); | |||||
| return (rc); | |||||
| } | |||||
| rc = find_manifest(filename); | |||||
| if (rc != VE_FINGERPRINT_WRONG && loaded_manifests) { | |||||
| if (severity <= VE_GUESS) | |||||
| severity = severity_guess(filename); | |||||
| if ((rc = verify_fd(fd, filename, off, &st)) >= 0) { | |||||
| if (verbose || severity > VE_WANT) { | |||||
| #if defined(VE_DEBUG_LEVEL) && VE_DEBUG_LEVEL > 0 | |||||
| printf("Verified %s %llu,%llu\n", filename, | |||||
| st.st_dev, st.st_ino); | |||||
| #else | |||||
| printf("Verified %s\n", filename); | |||||
| #endif | |||||
| } | |||||
| if (severity < VE_MUST) { /* not a kernel or module */ | |||||
| if ((cp = strrchr(filename, '/'))) { | |||||
| cp++; | |||||
| if (strncmp(cp, "loader.ve.", 10) == 0) { | |||||
| cp += 10; | |||||
| verify_tweak(cp, | |||||
| &accept_no_fp, &verbose, | |||||
| &verifying); | |||||
| } | |||||
| } | |||||
| } | |||||
| add_verify_status(&st, rc); | |||||
| ve_status_set(fd, rc); | |||||
| return (rc); | |||||
| } | |||||
| if (severity || verbose) | |||||
| printf("Unverified: %s\n", ve_error_get()); | |||||
| if (rc == VE_FINGERPRINT_UNKNOWN && severity < VE_MUST) | |||||
| rc = VE_UNVERIFIED_OK; | |||||
| else if (rc == VE_FINGERPRINT_NONE && severity < accept_no_fp) | |||||
| rc = VE_UNVERIFIED_OK; | |||||
| add_verify_status(&st, rc); | |||||
| } | |||||
| #ifdef LOADER_VERIEXEC_TESTING | |||||
| else if (rc != VE_FINGERPRINT_WRONG) { | |||||
| /* | |||||
| * We have not loaded any manifest and | |||||
| * not because of verication failure. | |||||
| * Most likely reason is we have none. | |||||
| * Allow boot to proceed if we are just testing. | |||||
| */ | |||||
| return (VE_UNVERIFIED_OK); | |||||
| } | |||||
| #endif | |||||
| if (rc == VE_FINGERPRINT_WRONG && severity > accept_no_fp) | |||||
| panic("cannot continue"); | |||||
| ve_status_set(fd, rc); | |||||
| return (rc); | |||||
| } | |||||
| /** | |||||
| * @brief get hex string for pcr value and export | |||||
| * | |||||
| * In case we are doing measured boot, provide | |||||
| * value of the "pcr" data we have accumulated. | |||||
| */ | |||||
| void | |||||
| verify_pcr_export(void) | |||||
| { | |||||
| #ifdef VE_PCR_SUPPORT | |||||
| char hexbuf[br_sha256_SIZE * 2 + 2]; | |||||
| unsigned char hbuf[br_sha256_SIZE]; | |||||
| char *hex; | |||||
| ssize_t hlen; | |||||
| hlen = ve_pcr_get(hbuf, sizeof(hbuf)); | |||||
| if (hlen > 0) { | |||||
| hex = hexdigest(hexbuf, sizeof(hexbuf), hbuf, hlen); | |||||
| if (hex) { | |||||
| hex[hlen*2] = '\0'; /* clobber newline */ | |||||
| setenv("loader.ve.pcr", hex, 1); | |||||
| } | |||||
| } | |||||
| #endif | |||||
| } | |||||