March 2020 - tor-commits - lists.torproject.org

[tor/release-0.4.3] Merge branch 'trove_2020_002_041' into maint-0.4.1
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 3c8a4b8fbdb42b2fa98ddec8b6d7ed3202201eb1 Merge: cec647ff3 916378103 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Mar 17 15:22:02 2020 -0400 Merge branch 'trove_2020_002_041' into maint-0.4.1 changes/ticket33119 | 8 +++++ src/feature/dirparse/parsecommon.c | 9 ++++- src/lib/crypt_ops/crypto_rsa.c | 27 +++++++++++---- src/lib/crypt_ops/crypto_rsa.h | 5 ++- src/lib/crypt_ops/crypto_rsa_nss.c | 14 +++++++- src/lib/crypt_ops/crypto_rsa_openssl.c | 63 ++++++++++++++++++++++++++++++++-- src/test/test_crypto.c | 39 +++++++++++++++++++++ 7 files changed, 154 insertions(+), 11 deletions(-)

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[tor/release-0.4.3] Port rsa_private_key_too_long() to work on OpenSSL 1.1.0.
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 0526801ed4caba4393942e62def2cb35f0f298b3 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 08:19:48 2020 -0400 Port rsa_private_key_too_long() to work on OpenSSL 1.1.0. --- src/lib/crypt_ops/crypto_rsa_openssl.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/lib/crypt_ops/crypto_rsa_openssl.c b/src/lib/crypt_ops/crypto_rsa_openssl.c index 6f3ac6fde..17eae24cc 100644 --- a/src/lib/crypt_ops/crypto_rsa_openssl.c +++ b/src/lib/crypt_ops/crypto_rsa_openssl.c @@ -573,6 +573,8 @@ rsa_private_key_too_long(RSA *rsa, int max_bits) { const BIGNUM *n, *e, *p, *q, *d, *dmp1, *dmq1, *iqmp; #ifdef OPENSSL_1_1_API + +#if OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,1) n = RSA_get0_n(rsa); e = RSA_get0_e(rsa); p = RSA_get0_p(rsa); @@ -581,6 +583,11 @@ rsa_private_key_too_long(RSA *rsa, int max_bits) dmp1 = RSA_get0_dmp1(rsa); dmq1 = RSA_get0_dmq1(rsa); iqmp = RSA_get0_iqmp(rsa); +#else + /* The accessors above did not exist in openssl 1.1.0. */ + p = q = dmp1 = dmq1 = iqmp = NULL; + RSA_get0_key(rsa, &n, &e, &d); +#endif if (RSA_bits(rsa) > max_bits) return true;

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[tor/release-0.4.3] Extract key length check into a new function, and check more fields.
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 8abdb394893a1704f885278f5f5d7913cdf516c9 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Mar 17 10:04:38 2020 -0400 Extract key length check into a new function, and check more fields. In the openssl that I have, it should be safe to only check the size of n. But if I'm wrong, or if other openssls work differently, we should check whether any of the fields are too large. Issue spotted by Teor. --- src/lib/crypt_ops/crypto_rsa_openssl.c | 57 +++++++++++++++++++++++++++++++--- 1 file changed, 52 insertions(+), 5 deletions(-) diff --git a/src/lib/crypt_ops/crypto_rsa_openssl.c b/src/lib/crypt_ops/crypto_rsa_openssl.c index 0db25f347..6f3ac6fde 100644 --- a/src/lib/crypt_ops/crypto_rsa_openssl.c +++ b/src/lib/crypt_ops/crypto_rsa_openssl.c @@ -33,6 +33,7 @@ ENABLE_GCC_WARNING(redundant-decls) #include "lib/encoding/binascii.h" #include <string.h> +#include <stdbool.h> /** Declaration for crypto_pk_t structure. */ struct crypto_pk_t @@ -564,6 +565,56 @@ crypto_pk_asn1_encode_private(const crypto_pk_t *pk, char *dest, return len; } +/** Check whether any component of a private key is too large in a way that + * seems likely to make verification too expensive. Return true if it's too + * long, and false otherwise. */ +static bool +rsa_private_key_too_long(RSA *rsa, int max_bits) +{ + const BIGNUM *n, *e, *p, *q, *d, *dmp1, *dmq1, *iqmp; +#ifdef OPENSSL_1_1_API + n = RSA_get0_n(rsa); + e = RSA_get0_e(rsa); + p = RSA_get0_p(rsa); + q = RSA_get0_q(rsa); + d = RSA_get0_d(rsa); + dmp1 = RSA_get0_dmp1(rsa); + dmq1 = RSA_get0_dmq1(rsa); + iqmp = RSA_get0_iqmp(rsa); + + if (RSA_bits(rsa) > max_bits) + return true; +#else + n = rsa->n; + e = rsa->e; + p = rsa->p; + q = rsa->q; + d = rsa->d; + dmp1 = rsa->dmp1; + dmq1 = rsa->dmq1; + iqmp = rsa->iqmp; +#endif + + if (n && BN_num_bits(n) > max_bits) + return true; + if (e && BN_num_bits(e) > max_bits) + return true; + if (p && BN_num_bits(p) > max_bits) + return true; + if (q && BN_num_bits(q) > max_bits) + return true; + if (d && BN_num_bits(d) > max_bits) + return true; + if (dmp1 && BN_num_bits(dmp1) > max_bits) + return true; + if (dmq1 && BN_num_bits(dmq1) > max_bits) + return true; + if (iqmp && BN_num_bits(iqmp) > max_bits) + return true; + + return false; +} + /** Decode an ASN.1-encoded private key from str; return the result on * success and NULL on failure. * @@ -584,11 +635,7 @@ crypto_pk_asn1_decode_private(const char *str, size_t len, int max_bits) crypto_openssl_log_errors(LOG_WARN,"decoding private key"); return NULL; } -#ifdef OPENSSL_1_1_API - if (max_bits >= 0 && RSA_bits(rsa) > max_bits) { -#else - if (max_bits >= 0 && rsa->n && BN_num_bits(rsa->n) > max_bits) { -#endif + if (max_bits >= 0 && rsa_private_key_too_long(rsa, max_bits)) { log_info(LD_CRYPTO, "Private key longer than expected."); RSA_free(rsa); return NULL;

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[tor/release-0.4.3] Merge branch 'maint-0.4.2' into maint-0.4.3
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 84f57b69f31bf47cbc902d853040cb099256ec6d Merge: e0d68ce84 758deaa47 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 08:20:16 2020 -0400 Merge branch 'maint-0.4.2' into maint-0.4.3 src/lib/crypt_ops/crypto_rsa_openssl.c | 7 +++++++ 1 file changed, 7 insertions(+)

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[tor/release-0.4.3] Merge branch 'maint-0.4.3' into release-0.4.3
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit d96ed976d947c2222a359066abe795eaf806272b Merge: 2d47cb984 84f57b69f Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 08:20:16 2020 -0400 Merge branch 'maint-0.4.3' into release-0.4.3 src/lib/crypt_ops/crypto_rsa_openssl.c | 7 +++++++ 1 file changed, 7 insertions(+)

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[tor/release-0.4.3] Pick release date, copy changelog to releasenotes.
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 27cc9093af1c7f7862fb242d4de9bd27a046831c Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 09:06:28 2020 -0400 Pick release date, copy changelog to releasenotes. --- ChangeLog | 2 +- ReleaseNotes | 102 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 103 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index 98c3d01ff..0759d065f 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,4 +1,4 @@ -Changes in version 0.4.3.3-alpha - 2020-03-?? +Changes in version 0.4.3.3-alpha - 2020-03-18 Tor 0.4.3.3-alpha fixes several bugs in previous releases, including TROVE-2020-002, a major denial-of-service vulnerability that affected all released Tor instances since 0.2.1.5-alpha. Using this diff --git a/ReleaseNotes b/ReleaseNotes index 7d981e2c4..73f0be95a 100644 --- a/ReleaseNotes +++ b/ReleaseNotes @@ -2,6 +2,108 @@ This document summarizes new features and bugfixes in each stable release of Tor. If you want to see more detailed descriptions of the changes in each development snapshot, see the ChangeLog file. +Changes in version 0.4.3.3-alpha - 2020-03-18 + Tor 0.4.3.3-alpha fixes several bugs in previous releases, including + TROVE-2020-002, a major denial-of-service vulnerability that affected + all released Tor instances since 0.2.1.5-alpha. Using this + vulnerability, an attacker could cause Tor instances to consume a huge + amount of CPU, disrupting their operations for several seconds or + minutes. This attack could be launched by anybody against a relay, or + by a directory cache against any client that had connected to it. The + attacker could launch this attack as much as they wanted, thereby + disrupting service or creating patterns that could aid in traffic + analysis. This issue was found by OSS-Fuzz, and is also tracked + as CVE-2020-10592. + + We do not have reason to believe that this attack is currently being + exploited in the wild, but nonetheless we advise everyone to upgrade + as soon as packages are available. + + o Major bugfixes (security, denial-of-service): + - Fix a denial-of-service bug that could be used by anyone to + consume a bunch of CPU on any Tor relay or authority, or by + directories to consume a bunch of CPU on clients or hidden + services. Because of the potential for CPU consumption to + introduce observable timing patterns, we are treating this as a + high-severity security issue. Fixes bug 33119; bugfix on + 0.2.1.5-alpha. Found by OSS-Fuzz. We are also tracking this issue + as TROVE-2020-002 and CVE-2020-10592. + + o Major bugfixes (circuit padding, memory leak): + - Avoid a remotely triggered memory leak in the case that a circuit + padding machine is somehow negotiated twice on the same circuit. + Fixes bug 33619; bugfix on 0.4.0.1-alpha. Found by Tobias Pulls. + This is also tracked as TROVE-2020-004 and CVE-2020-10593. + + o Major bugfixes (directory authority): + - Directory authorities will now send a 503 (not enough bandwidth) + code to clients when under bandwidth pressure. Known relays and + other authorities will always be answered regardless of the + bandwidth situation. Fixes bug 33029; bugfix on 0.1.2.5-alpha. + + o Minor features (diagnostic): + - Improve assertions and add some memory-poisoning code to try to + track down possible causes of a rare crash (32564) in the EWMA + code. Closes ticket 33290. + + o Minor features (directory authorities): + - Directory authorities now reject descriptors from relays running + Tor versions from the 0.2.9 and 0.4.0 series. The 0.3.5 series is + still allowed. Resolves ticket 32672. Patch by Neel Chauhan. + + o Minor features (usability): + - Include more information when failing to parse a configuration + value. This should make it easier to tell what's going wrong when + a configuration file doesn't parse. Closes ticket 33460. + + o Minor bugfix (relay, configuration): + - Warn if the ContactInfo field is not set, and tell the relay + operator that not having a ContactInfo field set might cause their + relay to get rejected in the future. Fixes bug 33361; bugfix + on 0.1.1.10-alpha. + + o Minor bugfixes (coding best practices checks): + - Allow the "practracker" script to read unicode files when using + Python 2. We made the script use unicode literals in 0.4.3.1-alpha, + but didn't change the codec for opening files. Fixes bug 33374; + bugfix on 0.4.3.1-alpha. + + o Minor bugfixes (continuous integration): + - Remove the buggy and unused mirroring job. Fixes bug 33213; bugfix + on 0.3.2.2-alpha. + + o Minor bugfixes (onion service v3, client): + - Remove a BUG() warning that would cause a stack trace if an onion + service descriptor was freed while we were waiting for a + rendezvous circuit to complete. Fixes bug 28992; bugfix + on 0.3.2.1-alpha. + + o Minor bugfixes (onion services v3): + - Fix an assertion failure that could result from a corrupted + ADD_ONION control port command. Found by Saibato. Fixes bug 33137; + bugfix on 0.3.3.1-alpha. This issue is also tracked + as TROVE-2020-003. + + o Documentation (manpage): + - Alphabetize the Server and Directory server sections of the tor + manpage. Also split Statistics options into their own section of + the manpage. Closes ticket 33188. Work by Swati Thacker as part of + Google Season of Docs. + - Document the __OwningControllerProcess torrc option and specify + its polling interval. Resolves issue 32971. + + o Testing (Travis CI): + - Remove a redundant distcheck job. Closes ticket 33194. + - Sort the Travis jobs in order of speed: putting the slowest jobs + first takes full advantage of Travis job concurrency. Closes + ticket 33194. + - Stop allowing the Chutney IPv6 Travis job to fail. This job was + previously configured to fast_finish (which requires + allow_failure), to speed up the build. Closes ticket 33195. + - When a Travis chutney job fails, use chutney's new "diagnostics.sh" + tool to produce detailed diagnostic output. Closes ticket 32792. + + Changes in version 0.4.2.6 - 2020-01-30 This is the second stable release in the 0.4.2.x series. It backports several bugfixes from 0.4.3.1-alpha, including some that had affected

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[tor/maint-0.4.3] Merge branch 'maint-0.4.2' into maint-0.4.3
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit e0d68ce84fe4536142d7f5e8987a08d9e93ac626 Merge: 6803373aa 85141a3a7 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Mar 17 15:22:36 2020 -0400 Merge branch 'maint-0.4.2' into maint-0.4.3 changes/ticket33119 | 8 +++++ src/feature/dirparse/parsecommon.c | 9 ++++- src/lib/crypt_ops/crypto_rsa.c | 27 +++++++++++---- src/lib/crypt_ops/crypto_rsa.h | 5 ++- src/lib/crypt_ops/crypto_rsa_nss.c | 14 +++++++- src/lib/crypt_ops/crypto_rsa_openssl.c | 63 ++++++++++++++++++++++++++++++++-- src/test/test_crypto.c | 39 +++++++++++++++++++++ 7 files changed, 154 insertions(+), 11 deletions(-)

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[tor/maint-0.4.3] Port rsa_private_key_too_long() to work on OpenSSL 1.1.0.
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 0526801ed4caba4393942e62def2cb35f0f298b3 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 08:19:48 2020 -0400 Port rsa_private_key_too_long() to work on OpenSSL 1.1.0. --- src/lib/crypt_ops/crypto_rsa_openssl.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/src/lib/crypt_ops/crypto_rsa_openssl.c b/src/lib/crypt_ops/crypto_rsa_openssl.c index 6f3ac6fde..17eae24cc 100644 --- a/src/lib/crypt_ops/crypto_rsa_openssl.c +++ b/src/lib/crypt_ops/crypto_rsa_openssl.c @@ -573,6 +573,8 @@ rsa_private_key_too_long(RSA *rsa, int max_bits) { const BIGNUM *n, *e, *p, *q, *d, *dmp1, *dmq1, *iqmp; #ifdef OPENSSL_1_1_API + +#if OPENSSL_VERSION_NUMBER >= OPENSSL_V_SERIES(1,1,1) n = RSA_get0_n(rsa); e = RSA_get0_e(rsa); p = RSA_get0_p(rsa); @@ -581,6 +583,11 @@ rsa_private_key_too_long(RSA *rsa, int max_bits) dmp1 = RSA_get0_dmp1(rsa); dmq1 = RSA_get0_dmq1(rsa); iqmp = RSA_get0_iqmp(rsa); +#else + /* The accessors above did not exist in openssl 1.1.0. */ + p = q = dmp1 = dmq1 = iqmp = NULL; + RSA_get0_key(rsa, &n, &e, &d); +#endif if (RSA_bits(rsa) > max_bits) return true;

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[tor/maint-0.4.3] Merge branch 'maint-0.4.2' into maint-0.4.3
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 84f57b69f31bf47cbc902d853040cb099256ec6d Merge: e0d68ce84 758deaa47 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Mar 18 08:20:16 2020 -0400 Merge branch 'maint-0.4.2' into maint-0.4.3 src/lib/crypt_ops/crypto_rsa_openssl.c | 7 +++++++ 1 file changed, 7 insertions(+)

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[tor/master] When parsing, reject >1024-bit RSA private keys sooner.
by nickm＠torproject.org 18 Mar '20

18 Mar '20

commit 9e1085c924133d7b73c7b0a42282fb13b34f28b8 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Feb 5 11:11:35 2020 -0500 When parsing, reject >1024-bit RSA private keys sooner. Private-key validation is fairly expensive for long keys in openssl, so we need to avoid it sooner. --- src/feature/dirparse/parsecommon.c | 3 ++- src/lib/crypt_ops/crypto_rsa.c | 27 +++++++++++++++++++++------ src/lib/crypt_ops/crypto_rsa.h | 5 ++++- src/lib/crypt_ops/crypto_rsa_nss.c | 14 +++++++++++++- src/lib/crypt_ops/crypto_rsa_openssl.c | 11 +++++++++-- 5 files changed, 49 insertions(+), 11 deletions(-) diff --git a/src/feature/dirparse/parsecommon.c b/src/feature/dirparse/parsecommon.c index 632f5adff..5b753f0f2 100644 --- a/src/feature/dirparse/parsecommon.c +++ b/src/feature/dirparse/parsecommon.c @@ -389,7 +389,8 @@ get_next_token(memarea_t *area, 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)) + if (crypto_pk_read_private_key1024_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; diff --git a/src/lib/crypt_ops/crypto_rsa.c b/src/lib/crypt_ops/crypto_rsa.c index c9189b0df..8fd8a8aa7 100644 --- a/src/lib/crypt_ops/crypto_rsa.c +++ b/src/lib/crypt_ops/crypto_rsa.c @@ -490,7 +490,7 @@ crypto_pk_write_private_key_to_string(crypto_pk_t *env, static int crypto_pk_read_from_string_generic(crypto_pk_t *env, const char *src, size_t len, int severity, - bool private_key) + bool private_key, int max_bits) { if (len == (size_t)-1) // "-1" indicates "use the length of the string." len = strlen(src); @@ -510,7 +510,7 @@ crypto_pk_read_from_string_generic(crypto_pk_t *env, const char *src, } crypto_pk_t *pk = private_key - ? crypto_pk_asn1_decode_private((const char*)buf, n) + ? crypto_pk_asn1_decode_private((const char*)buf, n, max_bits) : crypto_pk_asn1_decode((const char*)buf, n); if (! pk) { log_fn(severity, LD_CRYPTO, @@ -539,7 +539,8 @@ int crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src, size_t len) { - return crypto_pk_read_from_string_generic(env, src, len, LOG_INFO, false); + return crypto_pk_read_from_string_generic(env, src, len, LOG_INFO, false, + -1); } /** Read a PEM-encoded private key from the len-byte string src @@ -550,7 +551,21 @@ int crypto_pk_read_private_key_from_string(crypto_pk_t *env, const char *src, ssize_t len) { - return crypto_pk_read_from_string_generic(env, src, len, LOG_INFO, true); + return crypto_pk_read_from_string_generic(env, src, len, LOG_INFO, true, + -1); +} + +/** + * As crypto_pk_read_private_key_from_string(), but reject any key + * with a modulus longer than 1024 bits before doing any expensive + * validation on it. + */ +int +crypto_pk_read_private_key1024_from_string(crypto_pk_t *env, + const char *src, ssize_t len) +{ + return crypto_pk_read_from_string_generic(env, src, len, LOG_INFO, true, + 1024); } /** If a file is longer than this, we won't try to decode its private key */ @@ -578,7 +593,7 @@ crypto_pk_read_private_key_from_filename(crypto_pk_t *env, } int rv = crypto_pk_read_from_string_generic(env, buf, (ssize_t)st.st_size, - LOG_WARN, true); + LOG_WARN, true, -1); if (rv < 0) { log_warn(LD_CRYPTO, "Unable to decode private key from file %s", escaped(keyfile)); @@ -662,7 +677,7 @@ crypto_pk_base64_decode_private(const char *str, size_t len) goto out; } - pk = crypto_pk_asn1_decode_private(der, der_len); + pk = crypto_pk_asn1_decode_private(der, der_len, -1); out: memwipe(der, 0, len+1); diff --git a/src/lib/crypt_ops/crypto_rsa.h b/src/lib/crypt_ops/crypto_rsa.h index c1ea767f8..6d9cc8d30 100644 --- a/src/lib/crypt_ops/crypto_rsa.h +++ b/src/lib/crypt_ops/crypto_rsa.h @@ -61,6 +61,8 @@ int crypto_pk_read_public_key_from_string(crypto_pk_t *env, const char *src, size_t len); int crypto_pk_read_private_key_from_string(crypto_pk_t *env, const char *s, ssize_t len); +int crypto_pk_read_private_key1024_from_string(crypto_pk_t *env, + const char *src, ssize_t len); int crypto_pk_write_private_key_to_filename(crypto_pk_t *env, const char *fname); @@ -95,7 +97,8 @@ int crypto_pk_asn1_encode(const crypto_pk_t *pk, char *dest, size_t dest_len); crypto_pk_t *crypto_pk_asn1_decode(const char *str, size_t len); int crypto_pk_asn1_encode_private(const crypto_pk_t *pk, char *dest, size_t dest_len); -crypto_pk_t *crypto_pk_asn1_decode_private(const char *str, size_t len); +crypto_pk_t *crypto_pk_asn1_decode_private(const char *str, size_t len, + int max_bits); int crypto_pk_get_fingerprint(crypto_pk_t *pk, char *fp_out,int add_space); int crypto_pk_get_hashed_fingerprint(crypto_pk_t *pk, char *fp_out); void crypto_add_spaces_to_fp(char *out, size_t outlen, const char *in); diff --git a/src/lib/crypt_ops/crypto_rsa_nss.c b/src/lib/crypt_ops/crypto_rsa_nss.c index ad2ad38b6..4cf699067 100644 --- a/src/lib/crypt_ops/crypto_rsa_nss.c +++ b/src/lib/crypt_ops/crypto_rsa_nss.c @@ -679,9 +679,12 @@ crypto_pk_asn1_encode_private(const crypto_pk_t *pk, /** Given a buffer containing the DER representation of the * private key str, decode and return the result on success, or NULL * on failure. + * + * If max_bits is nonnegative, reject any key longer than max_bits + * without performing any expensive validation on it. */ crypto_pk_t * -crypto_pk_asn1_decode_private(const char *str, size_t len) +crypto_pk_asn1_decode_private(const char *str, size_t len, int max_bits) { tor_assert(str); tor_assert(len < INT_MAX); @@ -731,6 +734,15 @@ crypto_pk_asn1_decode_private(const char *str, size_t len) output = NULL; } + if (output) { + const int bits = SECKEY_PublicKeyStrengthInBits(output->pubkey); + if (max_bits > 0 && bits > max_bits) { + log_info(LD_CRYPTO, "Private key longer than expected."); + crypto_pk_free(output); + output = NULL; + } + } + if (slot) PK11_FreeSlot(slot); diff --git a/src/lib/crypt_ops/crypto_rsa_openssl.c b/src/lib/crypt_ops/crypto_rsa_openssl.c index fbdc76ccd..022a0dc09 100644 --- a/src/lib/crypt_ops/crypto_rsa_openssl.c +++ b/src/lib/crypt_ops/crypto_rsa_openssl.c @@ -566,9 +566,12 @@ crypto_pk_asn1_encode_private(const crypto_pk_t *pk, char *dest, /** Decode an ASN.1-encoded private key from str; return the result on * success and NULL on failure. + * + * If max_bits is nonnegative, reject any key longer than max_bits + * without performing any expensive validation on it. */ crypto_pk_t * -crypto_pk_asn1_decode_private(const char *str, size_t len) +crypto_pk_asn1_decode_private(const char *str, size_t len, int max_bits) { RSA *rsa; unsigned char *buf; @@ -578,7 +581,11 @@ crypto_pk_asn1_decode_private(const char *str, size_t len) rsa = d2i_RSAPrivateKey(NULL, &cp, len); tor_free(buf); if (!rsa) { - crypto_openssl_log_errors(LOG_WARN,"decoding public key"); + crypto_openssl_log_errors(LOG_WARN,"decoding private key"); + return NULL; + } + if (max_bits >= 0 && RSA_bits(rsa) > max_bits) { + log_info(LD_CRYPTO, "Private key longer than expected."); return NULL; } crypto_pk_t *result = crypto_new_pk_from_openssl_rsa_(rsa);

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