Stop memcpy'ing uncompressed consensuses when making diffs

This commit is contained in:
Nick Mathewson 2018-09-11 10:09:12 -04:00
parent 5595b21227
commit e014b72b73
4 changed files with 56 additions and 32 deletions

View File

@ -1387,19 +1387,21 @@ typedef struct consensus_diff_worker_job_t {
} consensus_diff_worker_job_t; } consensus_diff_worker_job_t;
/** Given a consensus_cache_entry_t, check whether it has a label claiming /** Given a consensus_cache_entry_t, check whether it has a label claiming
* that it was compressed. If so, uncompress its contents into <b>out</b> and * that it was compressed. If so, uncompress its contents into *<b>out</b> and
* set <b>outlen</b> to hold their size. If not, just copy the body into * set <b>outlen</b> to hold their size, and set *<b>owned_out</b> to a pointer
* <b>out</b> and set <b>outlen</b> to its length. Return 0 on success, * that the caller will need to free. If not, just set *<b>out</b> and
* -1 on failure. * <b>outlen</b> to its extent in memory. Return 0 on success, -1 on failure.
* **/
* In all cases, the output is nul-terminated. */
STATIC int STATIC int
uncompress_or_copy(char **out, size_t *outlen, uncompress_or_set_ptr(const char **out, size_t *outlen,
consensus_cache_entry_t *ent) char **owned_out,
consensus_cache_entry_t *ent)
{ {
const uint8_t *body; const uint8_t *body;
size_t bodylen; size_t bodylen;
*owned_out = NULL;
if (consensus_cache_entry_get_body(ent, &body, &bodylen) < 0) if (consensus_cache_entry_get_body(ent, &body, &bodylen) < 0)
return -1; return -1;
@ -1410,8 +1412,17 @@ uncompress_or_copy(char **out, size_t *outlen,
if (lv_compression) if (lv_compression)
method = compression_method_get_by_name(lv_compression); method = compression_method_get_by_name(lv_compression);
return tor_uncompress(out, outlen, (const char *)body, bodylen, int rv;
if (method == NO_METHOD) {
*out = (const char *)body;
*outlen = bodylen;
rv = 0;
} else {
rv = tor_uncompress(owned_out, outlen, (const char *)body, bodylen,
method, 1, LOG_WARN); method, 1, LOG_WARN);
*out = *owned_out;
}
return rv;
} }
/** /**
@ -1478,16 +1489,17 @@ consensus_diff_worker_threadfn(void *state_, void *work_)
char *consensus_diff; char *consensus_diff;
{ {
char *diff_from_nt = NULL, *diff_to_nt = NULL; const char *diff_from_nt = NULL, *diff_to_nt = NULL;
char *owned1 = NULL, *owned2 = NULL;
size_t diff_from_nt_len, diff_to_nt_len; size_t diff_from_nt_len, diff_to_nt_len;
if (uncompress_or_copy(&diff_from_nt, &diff_from_nt_len, if (uncompress_or_set_ptr(&diff_from_nt, &diff_from_nt_len, &owned1,
job->diff_from) < 0) { job->diff_from) < 0) {
return WQ_RPL_REPLY; return WQ_RPL_REPLY;
} }
if (uncompress_or_copy(&diff_to_nt, &diff_to_nt_len, if (uncompress_or_set_ptr(&diff_to_nt, &diff_to_nt_len, &owned2,
job->diff_to) < 0) { job->diff_to) < 0) {
tor_free(diff_from_nt); tor_free(owned1);
return WQ_RPL_REPLY; return WQ_RPL_REPLY;
} }
tor_assert(diff_from_nt); tor_assert(diff_from_nt);
@ -1497,11 +1509,11 @@ consensus_diff_worker_threadfn(void *state_, void *work_)
// XXXX inputs again, even though we already have that. Maybe it's time // XXXX inputs again, even though we already have that. Maybe it's time
// XXXX to change the API here? // XXXX to change the API here?
consensus_diff = consensus_diff_generate(diff_from_nt, consensus_diff = consensus_diff_generate(diff_from_nt,
strlen(diff_from_nt), diff_from_nt_len,
diff_to_nt, diff_to_nt,
strlen(diff_to_nt)); diff_to_nt_len);
tor_free(diff_from_nt); tor_free(owned1);
tor_free(diff_to_nt); tor_free(owned2);
} }
if (!consensus_diff) { if (!consensus_diff) {
/* Couldn't generate consensus; we'll leave the reply blank. */ /* Couldn't generate consensus; we'll leave the reply blank. */

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@ -68,8 +68,9 @@ STATIC consensus_cache_entry_t *cdm_cache_lookup_consensus(
STATIC int cdm_entry_get_sha3_value(uint8_t *digest_out, STATIC int cdm_entry_get_sha3_value(uint8_t *digest_out,
consensus_cache_entry_t *ent, consensus_cache_entry_t *ent,
const char *label); const char *label);
STATIC int uncompress_or_copy(char **out, size_t *outlen, STATIC int uncompress_or_set_ptr(const char **out, size_t *outlen,
consensus_cache_entry_t *ent); char **owned_out,
consensus_cache_entry_t *ent);
#endif /* defined(CONSDIFFMGR_PRIVATE) */ #endif /* defined(CONSDIFFMGR_PRIVATE) */
#endif /* !defined(TOR_CONSDIFFMGR_H) */ #endif /* !defined(TOR_CONSDIFFMGR_H) */

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@ -48,18 +48,27 @@ fuzz_main(const uint8_t *stdin_buf, size_t data_size)
size_t c2_len = data_size - c1_len - SEPLEN; size_t c2_len = data_size - c1_len - SEPLEN;
const char *c2 = (const char *)separator + SEPLEN; const char *c2 = (const char *)separator + SEPLEN;
const char *cp = memchr(c1, 0, c1_len);
if (cp)
c1_len = cp - c1;
cp = memchr(c2, 0, c2_len);
if (cp)
c2_len = cp - c2;
char *c3 = consensus_diff_generate(c1, c1_len, c2, c2_len); char *c3 = consensus_diff_generate(c1, c1_len, c2, c2_len);
if (c3) { if (c3) {
char *c4 = consensus_diff_apply(c1, c1_len, c3, strlen(c3)); char *c4 = consensus_diff_apply(c1, c1_len, c3, strlen(c3));
tor_assert(c4); tor_assert(c4);
if (strcmp(c2, c4)) { int equal = (c2_len == strlen(c4)) && fast_memeq(c2, c4, c2_len);
printf("%s\n", escaped(c1)); if (! equal) {
printf("%s\n", escaped(c2)); //printf("%s\n", escaped(c1));
//printf("%s\n", escaped(c2));
printf("%s\n", escaped(c3)); printf("%s\n", escaped(c3));
printf("%s\n", escaped(c4)); printf("%s\n", escaped(c4));
} }
tor_assert(! strcmp(c2, c4)); tor_assert(equal);
tor_free(c3); tor_free(c3);
tor_free(c4); tor_free(c4);
} }

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@ -191,14 +191,15 @@ lookup_apply_and_verify_diff(consensus_flavor_t flav,
consensus_cache_entry_incref(ent); consensus_cache_entry_incref(ent);
size_t size; size_t size;
char *diff_string = NULL; const char *diff_string = NULL;
int r = uncompress_or_copy(&diff_string, &size, ent); char *diff_owned = NULL;
int r = uncompress_or_set_ptr(&diff_string, &size, &diff_owned, ent);
consensus_cache_entry_decref(ent); consensus_cache_entry_decref(ent);
if (diff_string == NULL || r < 0) if (diff_string == NULL || r < 0)
return -1; return -1;
char *applied = consensus_diff_apply_(str1, diff_string); char *applied = consensus_diff_apply(str1, strlen(str1), diff_string, size);
tor_free(diff_string); tor_free(diff_owned);
if (applied == NULL) if (applied == NULL)
return -1; return -1;
@ -298,7 +299,8 @@ test_consdiffmgr_add(void *arg)
(void) arg; (void) arg;
time_t now = approx_time(); time_t now = approx_time();
char *body = NULL; const char *body = NULL;
char *body_owned = NULL;
consensus_cache_entry_t *ent = NULL; consensus_cache_entry_t *ent = NULL;
networkstatus_t *ns_tmp = fake_ns_new(FLAV_NS, now); networkstatus_t *ns_tmp = fake_ns_new(FLAV_NS, now);
@ -340,7 +342,7 @@ test_consdiffmgr_add(void *arg)
tt_assert(ent); tt_assert(ent);
consensus_cache_entry_incref(ent); consensus_cache_entry_incref(ent);
size_t s; size_t s;
r = uncompress_or_copy(&body, &s, ent); r = uncompress_or_set_ptr(&body, &s, &body_owned, ent);
tt_int_op(r, OP_EQ, 0); tt_int_op(r, OP_EQ, 0);
tt_int_op(s, OP_EQ, 4); tt_int_op(s, OP_EQ, 4);
tt_mem_op(body, OP_EQ, "quux", 4); tt_mem_op(body, OP_EQ, "quux", 4);
@ -353,7 +355,7 @@ test_consdiffmgr_add(void *arg)
networkstatus_vote_free(ns_tmp); networkstatus_vote_free(ns_tmp);
teardown_capture_of_logs(); teardown_capture_of_logs();
consensus_cache_entry_decref(ent); consensus_cache_entry_decref(ent);
tor_free(body); tor_free(body_owned);
} }
static void static void