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Merge branch 'trove-2017-009_025' into maint-0.2.5

This commit is contained in:
Nick Mathewson 2017-11-30 12:05:59 -05:00
parent 831d3b794d 75509dc827
commit a6a0c7a4ec
2 changed files with 13 additions and 1 deletions
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10
changes/trove-2017-009 Normal file
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@ -0,0 +1,10 @@
o Major bugfixes (security):
- When checking for replays in the INTRODUCE1 cell data for a (legacy)
hiddden service, correctly detect replays in the RSA-encrypted part of
the cell. We were previously checking for replays on the entire cell,
but those can be circumvented due to the malleability of Tor's legacy
hybrid encryption. This fix helps prevent a traffic confirmation
attack. Fixes bug 24244; bugfix on 0.2.4.1-alpha. This issue is also
tracked as TROVE-2017-009 and CVE-2017-8819.

4
src/or/rendservice.c
View File

@ -1162,6 +1162,7 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request,
time_t now = time(NULL);
time_t elapsed;
int replay;
size_t keylen;
/* Do some initial validation and logging before we parse the cell */
if (circuit->base_.purpose != CIRCUIT_PURPOSE_S_INTRO) {
@ -1245,9 +1246,10 @@ rend_service_introduce(origin_circuit_t *circuit, const uint8_t *request,
}
/* check for replay of PK-encrypted portion. */
keylen = crypto_pk_keysize(intro_key);
replay = replaycache_add_test_and_elapsed(
intro_point->accepted_intro_rsa_parts,
parsed_req->ciphertext, parsed_req->ciphertext_len,
parsed_req->ciphertext, MIN(parsed_req->ciphertext_len, keylen),
&elapsed);
if (replay) {