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- /* Copyright (c) 2016-2018, The Tor Project, Inc. */
- /* See LICENSE for licensing information */
- /**
- * \file parsecommon.c
- * \brief Common code to parse and validate various type of descriptors.
- **/
- #include "feature/dirparse/parsecommon.h"
- #include "lib/log/log.h"
- #include "lib/log/util_bug.h"
- #include "lib/encoding/binascii.h"
- #include "lib/container/smartlist.h"
- #include "lib/string/util_string.h"
- #include "lib/string/printf.h"
- #include "lib/memarea/memarea.h"
- #include "lib/crypt_ops/crypto_rsa.h"
- #include <string.h>
- #define MIN_ANNOTATION A_PURPOSE
- #define MAX_ANNOTATION A_UNKNOWN_
- #define ALLOC_ZERO(sz) memarea_alloc_zero(area,sz)
- #define ALLOC(sz) memarea_alloc(area,sz)
- #define STRDUP(str) memarea_strdup(area,str)
- #define STRNDUP(str,n) memarea_strndup(area,(str),(n))
- #define RET_ERR(msg) \
- STMT_BEGIN \
- if (tok) token_clear(tok); \
- tok = ALLOC_ZERO(sizeof(directory_token_t)); \
- tok->tp = ERR_; \
- tok->error = STRDUP(msg); \
- goto done_tokenizing; \
- STMT_END
- /** Free all resources allocated for <b>tok</b> */
- void
- token_clear(directory_token_t *tok)
- {
- if (tok->key)
- crypto_pk_free(tok->key);
- }
- /** Read all tokens from a string between <b>start</b> and <b>end</b>, and add
- * them to <b>out</b>. Parse according to the token rules in <b>table</b>.
- * Caller must free tokens in <b>out</b>. If <b>end</b> is NULL, use the
- * entire string.
- */
- int
- tokenize_string(memarea_t *area,
- const char *start, const char *end, smartlist_t *out,
- const token_rule_t *table, int flags)
- {
- const char **s;
- directory_token_t *tok = NULL;
- int counts[NIL_];
- int i;
- int first_nonannotation;
- int prev_len = smartlist_len(out);
- tor_assert(area);
- s = &start;
- if (!end) {
- end = start+strlen(start);
- } else {
- /* it's only meaningful to check for nuls if we got an end-of-string ptr */
- if (memchr(start, '\0', end-start)) {
- log_warn(LD_DIR, "parse error: internal NUL character.");
- return -1;
- }
- }
- for (i = 0; i < NIL_; ++i)
- counts[i] = 0;
- SMARTLIST_FOREACH(out, const directory_token_t *, t, ++counts[t->tp]);
- while (*s < end && (!tok || tok->tp != EOF_)) {
- tok = get_next_token(area, s, end, table);
- if (tok->tp == ERR_) {
- log_warn(LD_DIR, "parse error: %s", tok->error);
- token_clear(tok);
- return -1;
- }
- ++counts[tok->tp];
- smartlist_add(out, tok);
- *s = eat_whitespace_eos(*s, end);
- }
- if (flags & TS_NOCHECK)
- return 0;
- if ((flags & TS_ANNOTATIONS_OK)) {
- first_nonannotation = -1;
- for (i = 0; i < smartlist_len(out); ++i) {
- tok = smartlist_get(out, i);
- if (tok->tp < MIN_ANNOTATION || tok->tp > MAX_ANNOTATION) {
- first_nonannotation = i;
- break;
- }
- }
- if (first_nonannotation < 0) {
- log_warn(LD_DIR, "parse error: item contains only annotations");
- return -1;
- }
- for (i=first_nonannotation; i < smartlist_len(out); ++i) {
- tok = smartlist_get(out, i);
- if (tok->tp >= MIN_ANNOTATION && tok->tp <= MAX_ANNOTATION) {
- log_warn(LD_DIR, "parse error: Annotations mixed with keywords");
- return -1;
- }
- }
- if ((flags & TS_NO_NEW_ANNOTATIONS)) {
- if (first_nonannotation != prev_len) {
- log_warn(LD_DIR, "parse error: Unexpected annotations.");
- return -1;
- }
- }
- } else {
- for (i=0; i < smartlist_len(out); ++i) {
- tok = smartlist_get(out, i);
- if (tok->tp >= MIN_ANNOTATION && tok->tp <= MAX_ANNOTATION) {
- log_warn(LD_DIR, "parse error: no annotations allowed.");
- return -1;
- }
- }
- first_nonannotation = 0;
- }
- for (i = 0; table[i].t; ++i) {
- if (counts[table[i].v] < table[i].min_cnt) {
- log_warn(LD_DIR, "Parse error: missing %s element.", table[i].t);
- return -1;
- }
- if (counts[table[i].v] > table[i].max_cnt) {
- log_warn(LD_DIR, "Parse error: too many %s elements.", table[i].t);
- return -1;
- }
- if (table[i].pos & AT_START) {
- if (smartlist_len(out) < 1 ||
- (tok = smartlist_get(out, first_nonannotation))->tp != table[i].v) {
- log_warn(LD_DIR, "Parse error: first item is not %s.", table[i].t);
- return -1;
- }
- }
- if (table[i].pos & AT_END) {
- if (smartlist_len(out) < 1 ||
- (tok = smartlist_get(out, smartlist_len(out)-1))->tp != table[i].v) {
- log_warn(LD_DIR, "Parse error: last item is not %s.", table[i].t);
- return -1;
- }
- }
- }
- return 0;
- }
- /** Helper: parse space-separated arguments from the string <b>s</b> ending at
- * <b>eol</b>, and store them in the args field of <b>tok</b>. Store the
- * number of parsed elements into the n_args field of <b>tok</b>. Allocate
- * all storage in <b>area</b>. Return the number of arguments parsed, or
- * return -1 if there was an insanely high number of arguments. */
- static inline int
- get_token_arguments(memarea_t *area, directory_token_t *tok,
- const char *s, const char *eol)
- {
- /** Largest number of arguments we'll accept to any token, ever. */
- #define MAX_ARGS 512
- char *mem = memarea_strndup(area, s, eol-s);
- char *cp = mem;
- int j = 0;
- char *args[MAX_ARGS];
- memset(args, 0, sizeof(args));
- while (*cp) {
- if (j == MAX_ARGS)
- return -1;
- args[j++] = cp;
- cp = (char*)find_whitespace(cp);
- if (!cp || !*cp)
- break; /* End of the line. */
- *cp++ = '\0';
- cp = (char*)eat_whitespace(cp);
- }
- tok->n_args = j;
- tok->args = memarea_memdup(area, args, j*sizeof(char*));
- return j;
- #undef MAX_ARGS
- }
- /** Helper: make sure that the token <b>tok</b> with keyword <b>kwd</b> obeys
- * the object syntax of <b>o_syn</b>. Allocate all storage in <b>area</b>.
- * Return <b>tok</b> on success, or a new ERR_ token if the token didn't
- * conform to the syntax we wanted.
- **/
- static inline directory_token_t *
- token_check_object(memarea_t *area, const char *kwd,
- directory_token_t *tok, obj_syntax o_syn)
- {
- char ebuf[128];
- switch (o_syn) {
- case NO_OBJ:
- /* No object is allowed for this token. */
- if (tok->object_body) {
- tor_snprintf(ebuf, sizeof(ebuf), "Unexpected object for %s", kwd);
- RET_ERR(ebuf);
- }
- if (tok->key) {
- tor_snprintf(ebuf, sizeof(ebuf), "Unexpected public key for %s", kwd);
- RET_ERR(ebuf);
- }
- break;
- case NEED_OBJ:
- /* There must be a (non-key) object. */
- if (!tok->object_body) {
- tor_snprintf(ebuf, sizeof(ebuf), "Missing object for %s", kwd);
- RET_ERR(ebuf);
- }
- break;
- case NEED_KEY_1024: /* There must be a 1024-bit public key. */
- case NEED_SKEY_1024: /* There must be a 1024-bit private key. */
- if (tok->key && crypto_pk_num_bits(tok->key) != PK_BYTES*8) {
- tor_snprintf(ebuf, sizeof(ebuf), "Wrong size on key for %s: %d bits",
- kwd, crypto_pk_num_bits(tok->key));
- RET_ERR(ebuf);
- }
- /* fall through */
- case NEED_KEY: /* There must be some kind of key. */
- if (!tok->key) {
- tor_snprintf(ebuf, sizeof(ebuf), "Missing public key for %s", kwd);
- RET_ERR(ebuf);
- }
- if (o_syn != NEED_SKEY_1024) {
- if (crypto_pk_key_is_private(tok->key)) {
- tor_snprintf(ebuf, sizeof(ebuf),
- "Private key given for %s, which wants a public key", kwd);
- RET_ERR(ebuf);
- }
- } else { /* o_syn == NEED_SKEY_1024 */
- if (!crypto_pk_key_is_private(tok->key)) {
- tor_snprintf(ebuf, sizeof(ebuf),
- "Public key given for %s, which wants a private key", kwd);
- RET_ERR(ebuf);
- }
- }
- break;
- case OBJ_OK:
- /* Anything goes with this token. */
- break;
- }
- done_tokenizing:
- return tok;
- }
- /** Helper function: read the next token from *s, advance *s to the end of the
- * token, and return the parsed token. Parse *<b>s</b> according to the list
- * of tokens in <b>table</b>.
- */
- directory_token_t *
- get_next_token(memarea_t *area,
- const char **s, const char *eos, const token_rule_t *table)
- {
- /** Reject any object at least this big; it is probably an overflow, an
- * attack, a bug, or some other nonsense. */
- #define MAX_UNPARSED_OBJECT_SIZE (128*1024)
- /** Reject any line at least this big; it is probably an overflow, an
- * attack, a bug, or some other nonsense. */
- #define MAX_LINE_LENGTH (128*1024)
- const char *next, *eol, *obstart;
- size_t obname_len;
- int i;
- directory_token_t *tok;
- obj_syntax o_syn = NO_OBJ;
- char ebuf[128];
- const char *kwd = "";
- tor_assert(area);
- tok = ALLOC_ZERO(sizeof(directory_token_t));
- tok->tp = ERR_;
- /* Set *s to first token, eol to end-of-line, next to after first token */
- *s = eat_whitespace_eos(*s, eos); /* eat multi-line whitespace */
- tor_assert(eos >= *s);
- eol = memchr(*s, '\n', eos-*s);
- if (!eol)
- eol = eos;
- if (eol - *s > MAX_LINE_LENGTH) {
- RET_ERR("Line far too long");
- }
- next = find_whitespace_eos(*s, eol);
- if (!strcmp_len(*s, "opt", next-*s)) {
- /* Skip past an "opt" at the start of the line. */
- *s = eat_whitespace_eos_no_nl(next, eol);
- next = find_whitespace_eos(*s, eol);
- } else if (*s == eos) { /* If no "opt", and end-of-line, line is invalid */
- RET_ERR("Unexpected EOF");
- }
- /* Search the table for the appropriate entry. (I tried a binary search
- * instead, but it wasn't any faster.) */
- for (i = 0; table[i].t ; ++i) {
- if (!strcmp_len(*s, table[i].t, next-*s)) {
- /* We've found the keyword. */
- kwd = table[i].t;
- tok->tp = table[i].v;
- o_syn = table[i].os;
- *s = eat_whitespace_eos_no_nl(next, eol);
- /* We go ahead whether there are arguments or not, so that tok->args is
- * always set if we want arguments. */
- if (table[i].concat_args) {
- /* The keyword takes the line as a single argument */
- tok->args = ALLOC(sizeof(char*));
- tok->args[0] = STRNDUP(*s,eol-*s); /* Grab everything on line */
- tok->n_args = 1;
- } else {
- /* This keyword takes multiple arguments. */
- if (get_token_arguments(area, tok, *s, eol)<0) {
- tor_snprintf(ebuf, sizeof(ebuf),"Far too many arguments to %s", kwd);
- RET_ERR(ebuf);
- }
- *s = eol;
- }
- if (tok->n_args < table[i].min_args) {
- tor_snprintf(ebuf, sizeof(ebuf), "Too few arguments to %s", kwd);
- RET_ERR(ebuf);
- } else if (tok->n_args > table[i].max_args) {
- tor_snprintf(ebuf, sizeof(ebuf), "Too many arguments to %s", kwd);
- RET_ERR(ebuf);
- }
- break;
- }
- }
- if (tok->tp == ERR_) {
- /* No keyword matched; call it an "K_opt" or "A_unrecognized" */
- if (*s < eol && **s == '@')
- tok->tp = A_UNKNOWN_;
- else
- tok->tp = K_OPT;
- tok->args = ALLOC(sizeof(char*));
- tok->args[0] = STRNDUP(*s, eol-*s);
- tok->n_args = 1;
- o_syn = OBJ_OK;
- }
- /* Check whether there's an object present */
- *s = eat_whitespace_eos(eol, eos); /* Scan from end of first line */
- tor_assert(eos >= *s);
- eol = memchr(*s, '\n', eos-*s);
- if (!eol || eol-*s<11 || strcmpstart(*s, "-----BEGIN ")) /* No object. */
- goto check_object;
- obstart = *s; /* Set obstart to start of object spec */
- if (eol - *s <= 16 || memchr(*s+11,'\0',eol-*s-16) || /* no short lines, */
- strcmp_len(eol-5, "-----", 5) || /* nuls or invalid endings */
- (eol-*s) > MAX_UNPARSED_OBJECT_SIZE) { /* name too long */
- RET_ERR("Malformed object: bad begin line");
- }
- tok->object_type = STRNDUP(*s+11, eol-*s-16);
- obname_len = eol-*s-16; /* store objname length here to avoid a strlen() */
- *s = eol+1; /* Set *s to possible start of object data (could be eos) */
- /* Go to the end of the object */
- next = tor_memstr(*s, eos-*s, "-----END ");
- if (!next) {
- RET_ERR("Malformed object: missing object end line");
- }
- tor_assert(eos >= next);
- eol = memchr(next, '\n', eos-next);
- if (!eol) /* end-of-line marker, or eos if there's no '\n' */
- eol = eos;
- /* Validate the ending tag, which should be 9 + NAME + 5 + eol */
- if ((size_t)(eol-next) != 9+obname_len+5 ||
- strcmp_len(next+9, tok->object_type, obname_len) ||
- strcmp_len(eol-5, "-----", 5)) {
- tor_snprintf(ebuf, sizeof(ebuf), "Malformed object: mismatched end tag %s",
- tok->object_type);
- ebuf[sizeof(ebuf)-1] = '\0';
- RET_ERR(ebuf);
- }
- if (next - *s > MAX_UNPARSED_OBJECT_SIZE)
- RET_ERR("Couldn't parse object: missing footer or object much too big.");
- if (!strcmp(tok->object_type, "RSA PUBLIC KEY")) { /* If it's a public key */
- tok->key = crypto_pk_new();
- if (crypto_pk_read_public_key_from_string(tok->key, obstart, eol-obstart))
- RET_ERR("Couldn't parse public key.");
- } else if (!strcmp(tok->object_type, "RSA PRIVATE KEY")) { /* private key */
- tok->key = crypto_pk_new();
- if (crypto_pk_read_private_key_from_string(tok->key, obstart, eol-obstart))
- RET_ERR("Couldn't parse private key.");
- } else { /* If it's something else, try to base64-decode it */
- int r;
- tok->object_body = ALLOC(next-*s); /* really, this is too much RAM. */
- r = base64_decode(tok->object_body, next-*s, *s, next-*s);
- if (r<0)
- RET_ERR("Malformed object: bad base64-encoded data");
- tok->object_size = r;
- }
- *s = eol;
- check_object:
- tok = token_check_object(area, kwd, tok, o_syn);
- done_tokenizing:
- return tok;
- #undef RET_ERR
- #undef ALLOC
- #undef ALLOC_ZERO
- #undef STRDUP
- #undef STRNDUP
- }
- /** Find the first token in <b>s</b> whose keyword is <b>keyword</b>; fail
- * with an assert if no such keyword is found.
- */
- directory_token_t *
- find_by_keyword_(smartlist_t *s, directory_keyword keyword,
- const char *keyword_as_string)
- {
- directory_token_t *tok = find_opt_by_keyword(s, keyword);
- if (PREDICT_UNLIKELY(!tok)) {
- log_err(LD_BUG, "Missing %s [%d] in directory object that should have "
- "been validated. Internal error.", keyword_as_string, (int)keyword);
- tor_assert(tok);
- }
- return tok;
- }
- /** Find the first token in <b>s</b> whose keyword is <b>keyword</b>; return
- * NULL if no such keyword is found.
- */
- directory_token_t *
- find_opt_by_keyword(const smartlist_t *s, directory_keyword keyword)
- {
- SMARTLIST_FOREACH(s, directory_token_t *, t, if (t->tp == keyword) return t);
- return NULL;
- }
- /** If there are any directory_token_t entries in <b>s</b> whose keyword is
- * <b>k</b>, return a newly allocated smartlist_t containing all such entries,
- * in the same order in which they occur in <b>s</b>. Otherwise return
- * NULL. */
- smartlist_t *
- find_all_by_keyword(const smartlist_t *s, directory_keyword k)
- {
- smartlist_t *out = NULL;
- SMARTLIST_FOREACH(s, directory_token_t *, t,
- if (t->tp == k) {
- if (!out)
- out = smartlist_new();
- smartlist_add(out, t);
- });
- return out;
- }
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