diff --git a/lib/libsecureboot/verify_file.c b/lib/libsecureboot/verify_file.c index 9773b02e5a1d..22f3f06b0eda 100644 --- a/lib/libsecureboot/verify_file.c +++ b/lib/libsecureboot/verify_file.c @@ -1,558 +1,561 @@ /*- * Copyright (c) 2017-2020, 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 __FBSDID("$FreeBSD$"); #include #include #include #include #include "libsecureboot.h" #include #include #ifdef UNIT_TEST # include # 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 *Destdir; extern size_t DestdirLen; 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. */ +#ifndef SOPEN_MAX +#define SOPEN_MAX 64 +#endif 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; }; int is_verified(struct stat *stp) { struct verify_status *vsp; if (stp->st_ino > 0) { 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. */ 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) { #ifdef UNIT_TEST if (DestdirLen > 0 && strncmp(name, Destdir, DestdirLen) == 0) { name += DestdirLen; if (prefix && strncmp(prefix, Destdir, DestdirLen) == 0) prefix += DestdirLen; } #endif 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 = VE_VERIFIED; } 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); if (strcmp(cp, ".4th") == 0 || strcmp(cp, ".lua") == 0 || strcmp(cp, ".rc") == 0) return (VE_MUST); } return (VE_WANT); } static int Verifying = -1; /* 0 if not verifying */ static void verify_tweak(int fd, off_t off, struct stat *stp, char *tweak, int *accept_no_fp, int *verbose) { 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; } else if (strncmp(tweak, "trust", 5) == 0) { /* content is trust anchor to add or revoke */ unsigned char *ucp; size_t num; if (off > 0) lseek(fd, 0, SEEK_SET); ucp = read_fd(fd, stp->st_size); if (ucp == NULL) return; if (strstr(tweak, "revoke")) { num = ve_trust_anchors_revoke(ucp, stp->st_size); DEBUG_PRINTF(3, ("revoked %d trust anchors\n", (int) num)); } else { num = ve_trust_anchors_add_buf(ucp, stp->st_size); DEBUG_PRINTF(3, ("added %d trust anchors\n", (int) num)); } } } #ifndef VE_DEBUG_LEVEL # define VE_DEBUG_LEVEL 0 #endif static int getenv_int(const char *var, int def) { const char *cp; char *ep; long val; val = def; cp = getenv(var); if (cp && *cp) { val = strtol(cp, &ep, 0); if ((ep && *ep) || val != (int)val) { val = def; } } return (int)val; } /** * @brief prepare to verify an open file * * @param[in] fd * open descriptor * * @param[in] filename * path we opened and will use to lookup fingerprint * * @param[in] stp * stat pointer so we can check file type */ int verify_prep(int fd, const char *filename, off_t off, struct stat *stp, const char *caller) { int rc; if (Verifying < 0) { Verifying = ve_trust_init(); #ifndef UNIT_TEST ve_debug_set(getenv_int("VE_DEBUG_LEVEL", 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(); ve_anchor_verbose_set(1); } } if (!Verifying || fd < 0) return (0); if (stp) { if (fstat(fd, stp) < 0 || !S_ISREG(stp->st_mode)) return (0); } DEBUG_PRINTF(2, ("verify_prep: caller=%s,fd=%d,name='%s',off=%lld,dev=%lld,ino=%lld\n", caller, fd, filename, (long long)off, (long long)stp->st_dev, (long long)stp->st_ino)); rc = is_verified(stp); DEBUG_PRINTF(4,("verify_prep: is_verified()->%d\n", rc)); if (rc == VE_NOT_CHECKED) { rc = find_manifest(filename); } else { ve_status_set(fd, rc); } return (rc); } /** * @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, const char *caller) { static int once; static int accept_no_fp = ACCEPT_NO_FP_DEFAULT; static int verbose = VE_VERBOSE_DEFAULT; struct stat st; char *cp; int rc; rc = verify_prep(fd, filename, off, &st, caller); if (!rc) return (0); if (!once) { once++; verbose = getenv_int("VE_VERBOSE", VE_VERBOSE_DEFAULT); } if (rc != VE_FINGERPRINT_WRONG && loaded_manifests) { if (severity <= VE_GUESS) severity = severity_guess(filename); #ifdef VE_PCR_SUPPORT /* * Only update pcr with things that must verify * these tend to be processed in a more deterministic * order, which makes our pseudo pcr more useful. */ ve_pcr_updating_set((severity == VE_MUST)); #endif #ifdef UNIT_TEST if (DestdirLen > 0 && strncmp(filename, Destdir, DestdirLen) == 0) { filename += DestdirLen; } #endif if ((rc = verify_fd(fd, filename, off, &st)) >= 0) { if (verbose || severity > VE_WANT) { #if defined(VE_DEBUG_LEVEL) && VE_DEBUG_LEVEL > 0 printf("%serified %s %llu,%llu\n", (rc == VE_FINGERPRINT_IGNORE) ? "Unv" : "V", filename, (long long)st.st_dev, (long long)st.st_ino); #else printf("%serified %s\n", (rc == VE_FINGERPRINT_IGNORE) ? "Unv" : "V", 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(fd, off, &st, cp, &accept_no_fp, &verbose); } } } add_verify_status(&st, rc); ve_status_set(fd, rc); return (rc); } if (severity || verbose || rc == VE_FINGERPRINT_WRONG) 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 *hinfo; 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); DEBUG_PRINTF(1, ("%s: setenv(loader.ve.pcr, %s\n", __func__, hex)); hinfo = ve_pcr_hashed_get(1); if (hinfo) { setenv("loader.ve.hashed", hinfo, 1); DEBUG_PRINTF(1, ("%s: setenv(loader.ve.hashed, %s\n", __func__, hinfo)); if ((hlen = strlen(hinfo)) > KENV_MVALLEN) { /* * bump kenv_mvallen * roundup to multiple of KENV_MVALLEN */ char mvallen[16]; hlen += KENV_MVALLEN - (hlen % KENV_MVALLEN); if (snprintf(mvallen, sizeof(mvallen), "%d", (int) hlen) < sizeof(mvallen)) setenv("kenv_mvallen", mvallen, 1); } free(hinfo); } } } #endif }