commit 9cbc166ea038e51baec92c8f37a2646c76a97480 Author: Nick Mathewson <nickm@torproject.org> Date: Mon Sep 9 15:21:01 2019 -0400 Extract the body-copying portion of microdesc parsing This code is logically independent of the rest of the function, and goes better in its own function. This is almost purely code movement; I suggest reviewing with --color-moved. --- src/feature/dirparse/microdesc_parse.c | 59 +++++++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 16 deletions(-) diff --git a/src/feature/dirparse/microdesc_parse.c b/src/feature/dirparse/microdesc_parse.c index e77166066..621e3c10d 100644 --- a/src/feature/dirparse/microdesc_parse.c +++ b/src/feature/dirparse/microdesc_parse.c @@ -123,6 +123,45 @@ saved_location_to_string(saved_location_t where) return location; } +/** + * Given a microdescriptor stored in <b>where</b> which starts at <b>s</b>, + * which ends at <b>start_of_next_microdescriptor</b>, and which is located + * within a larger document beginning at <b>start</b>: Fill in the body, + * bodylen, bodylen, saved_location, off, and digest fields of <b>md</b> as + * appropriate. + * + * The body field will be an alias within <b>s</b> if <b>saved_location</b> + * is SAVED_IN_CACHE, and will be copied into body and nul-terminated + * otherwise. + **/ +static int +microdesc_extract_body(microdesc_t *md, + const char *start, + const char *s, const char *start_of_next_microdesc, + saved_location_t where) +{ + const int copy_body = (where != SAVED_IN_CACHE); + + const char *cp = tor_memstr(s, start_of_next_microdesc-s, + "onion-key"); + const int no_onion_key = (cp == NULL); + if (no_onion_key) { + cp = s; /* So that we have *some* junk to put in the body */ + } + + md->bodylen = start_of_next_microdesc - cp; + md->saved_location = where; + if (copy_body) + md->body = tor_memdup_nulterm(cp, md->bodylen); + else + md->body = (char*)cp; + md->off = cp - start; + + crypto_digest256(md->digest, md->body, md->bodylen, DIGEST_SHA256); + + return no_onion_key ? -1 : 0; +} + /** Parse as many microdescriptors as are found from the string starting at * <b>s</b> and ending at <b>eos</b>. If allow_annotations is set, read any * annotations we recognize and ignore ones we don't. @@ -147,7 +186,6 @@ microdescs_parse_from_string(const char *s, const char *eos, const char *start = s; const char *start_of_next_microdesc; int flags = allow_annotations ? TS_ANNOTATIONS_OK : 0; - const int copy_body = (where != SAVED_IN_CACHE); directory_token_t *tok; @@ -169,23 +207,12 @@ microdescs_parse_from_string(const char *s, const char *eos, md = tor_malloc_zero(sizeof(microdesc_t)); uint8_t md_digest[DIGEST256_LEN]; { - const char *cp = tor_memstr(s, start_of_next_microdesc-s, - "onion-key"); - const int no_onion_key = (cp == NULL); - if (no_onion_key) { - cp = s; /* So that we have *some* junk to put in the body */ - } + int body_not_found = microdesc_extract_body(md, start, s, + start_of_next_microdesc, + where) < 0; - md->bodylen = start_of_next_microdesc - cp; - md->saved_location = where; - if (copy_body) - md->body = tor_memdup_nulterm(cp, md->bodylen); - else - md->body = (char*)cp; - md->off = cp - start; - crypto_digest256(md->digest, md->body, md->bodylen, DIGEST_SHA256); memcpy(md_digest, md->digest, DIGEST256_LEN); - if (no_onion_key) { + if (body_not_found) { log_fn(LOG_PROTOCOL_WARN, LD_DIR, "Malformed or truncated descriptor"); goto next; }