February 2017 - tor-commits - lists.torproject.org

[tor/release-0.2.9] Merge branch 'maint-0.2.6' into maint-0.2.7
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 5c4235888af142b72aa6b88737bcf1020797e35c Merge: 75fe218 e778a41 Author: Roger Dingledine <arma(a)torproject.org> Date: Mon Feb 13 15:28:50 2017 -0500 Merge branch 'maint-0.2.6' into maint-0.2.7 changes/bug20384 | 10 ++++++++++ 1 file changed, 10 insertions(+)

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[tor/release-0.2.9] changes file for removing compare-by-subtraction pattern
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 9f71fde146712d4fafbf3e967d560b18aed64794 Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Feb 14 16:32:59 2017 -0500 changes file for removing compare-by-subtraction pattern --- changes/bug21278_extras | 3 +++ 1 file changed, 3 insertions(+) diff --git a/changes/bug21278_extras b/changes/bug21278_extras new file mode 100644 index 0000000..ffdf4a0 --- /dev/null +++ b/changes/bug21278_extras @@ -0,0 +1,3 @@ + o Minor bugfixes (code correctness): + - Repair a couple of (unreachable or harmless) cases of the risky + comparison-by-subtraction pattern that caused bug 21278.

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[tor/release-0.2.9] Merge branch 'maint-0.2.7' into maint-0.2.8
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 1ebdae61711ec03ce49af2f356756b5db9587412 Merge: 9b90d51 ed80684 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Feb 15 07:47:28 2017 -0500 Merge branch 'maint-0.2.7' into maint-0.2.8 changes/bug20384 | 10 ++++++++++ changes/trove-2017-001.2 | 8 ++++++++ src/or/routerparse.c | 49 +++++++++++++++++++++++++++++------------------- 3 files changed, 48 insertions(+), 19 deletions(-)

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[tor/release-0.2.9] Merge branch 'maint-0.2.6' into maint-0.2.7
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit ed806843dc8e7942a2a0abfbb2ae374e11963feb Merge: 75fe218 3781f24 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Feb 15 07:47:21 2017 -0500 Merge branch 'maint-0.2.6' into maint-0.2.7 changes/bug20384 | 10 ++++++++++ changes/trove-2017-001.2 | 8 ++++++++ src/or/routerparse.c | 49 +++++++++++++++++++++++++++++------------------- 3 files changed, 48 insertions(+), 19 deletions(-)

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[tor/release-0.2.9] Merge branch 'maint-0.2.8' into maint-0.2.9
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 4a2afd5b33f02ed3e5eb591dd29537fa4f69399f Merge: a86f95d 9ff7618 Author: Roger Dingledine <arma(a)torproject.org> Date: Mon Feb 13 15:41:20 2017 -0500 Merge branch 'maint-0.2.8' into maint-0.2.9

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[tor/release-0.2.9] Merge branch 'maint-0.2.5' into maint-0.2.6
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit e778a411b9e75ad2c1b46a6624d586a6f4a0c554 Merge: 43c18b1 144ec3d Author: Roger Dingledine <arma(a)torproject.org> Date: Mon Feb 13 15:27:57 2017 -0500 Merge branch 'maint-0.2.5' into maint-0.2.6 changes/bug20384 | 10 ++++++++++ 1 file changed, 10 insertions(+)

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[tor/release-0.2.9] Avoid integer underflow in tor_version_compare.
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 194e31057fbf07d6bdf4b62d26e1a9db334e5f1c Author: Nick Mathewson <nickm(a)torproject.org> Date: Tue Feb 7 10:58:02 2017 -0500 Avoid integer underflow in tor_version_compare. Fix for TROVE-2017-001 and bug 21278. (Note: Instead of handling signed ints "correctly", we keep the old behavior, except for the part where we would crash with -ftrapv.) --- changes/trove-2017-001.2 | 8 ++++++++ src/or/routerparse.c | 49 +++++++++++++++++++++++++++++------------------- 2 files changed, 38 insertions(+), 19 deletions(-) diff --git a/changes/trove-2017-001.2 b/changes/trove-2017-001.2 new file mode 100644 index 0000000..3ef073c --- /dev/null +++ b/changes/trove-2017-001.2 @@ -0,0 +1,8 @@ + o Major bugfixes (parsing): + - Fix an integer underflow bug when comparing malformed Tor versions. + This bug is harmless, except when Tor has been built with + --enable-expensive-hardening, which would turn it into a crash; + or on Tor 0.2.9.1-alpha through Tor 0.2.9.8, which were built with + -ftrapv by default. + Part of TROVE-2017-001. Fixes bug 21278; bugfix on + 0.0.8pre1. Found by OSS-Fuzz. diff --git a/src/or/routerparse.c b/src/or/routerparse.c index 71373ce..1243035 100644 --- a/src/or/routerparse.c +++ b/src/or/routerparse.c @@ -4545,26 +4545,37 @@ tor_version_compare(tor_version_t *a, tor_version_t *b) int i; tor_assert(a); tor_assert(b); - if ((i = a->major - b->major)) - return i; - else if ((i = a->minor - b->minor)) - return i; - else if ((i = a->micro - b->micro)) - return i; - else if ((i = a->status - b->status)) - return i; - else if ((i = a->patchlevel - b->patchlevel)) - return i; - else if ((i = strcmp(a->status_tag, b->status_tag))) - return i; - else if ((i = a->svn_revision - b->svn_revision)) - return i; - else if ((i = a->git_tag_len - b->git_tag_len)) - return i; - else if (a->git_tag_len) - return fast_memcmp(a->git_tag, b->git_tag, a->git_tag_len); + + /* We take this approach to comparison to ensure the same (bogus!) behavior + * on all inputs as we would have seen before bug #21278 was fixed. The + * only important difference here is that this method doesn't cause + * a signed integer underflow. + */ +#define CMP(field) do { \ + unsigned aval = (unsigned) a->field; \ + unsigned bval = (unsigned) b->field; \ + int result = (int) (aval - bval); \ + if (result < 0) \ + return -1; \ + else if (result > 0) \ + return 1; \ + } while (0) + + CMP(major); + CMP(minor); + CMP(micro); + CMP(status); + CMP(patchlevel); + if ((i = strcmp(a->status_tag, b->status_tag))) + return i; + CMP(svn_revision); + CMP(git_tag_len); + if (a->git_tag_len) + return fast_memcmp(a->git_tag, b->git_tag, a->git_tag_len); else - return 0; + return 0; + +#undef CMP } /** Return true iff versions <b>a</b> and <b>b</b> belong to the same series.

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[tor/release-0.2.9] Prevent int underflow in dirvote.c compare_vote_rs_.
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit a0ef3cf0880e3cd343977b3fcbd0a2e7572f0cb4 Author: Nick Mathewson <nickm(a)torproject.org> Date: Mon Feb 13 14:07:35 2017 -0500 Prevent int underflow in dirvote.c compare_vote_rs_. This should be "impossible" without making a SHA1 collision, but let's not keep the assumption that SHA1 collisions are super-hard. This prevents another case related to 21278. There should be no behavioral change unless -ftrapv is on. --- src/or/dirvote.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-) diff --git a/src/or/dirvote.c b/src/or/dirvote.c index 2c10e78..738ab35 100644 --- a/src/or/dirvote.c +++ b/src/or/dirvote.c @@ -421,16 +421,30 @@ compare_vote_rs(const vote_routerstatus_t *a, const vote_routerstatus_t *b) b->status.descriptor_digest, DIGEST_LEN))) return r; - if ((r = (int)(b->status.published_on - a->status.published_on))) - return r; + /* If we actually reached this point, then the identities and + * the descriptor digests matched, so somebody is making SHA1 collisions. + */ +#define CMP_FIELD(utype, itype, field) do { \ + utype aval = (utype) (itype) a->status.field; \ + utype bval = (utype) (itype) b->status.field; \ + utype u = bval - aval; \ + itype r2 = (itype) u; \ + if (r2 < 0) { \ + return -1; \ + } else if (r2 > 0) { \ + return 1; \ + } \ + } while (0) + + CMP_FIELD(uint64_t, int64_t, published_on); + if ((r = strcmp(b->status.nickname, a->status.nickname))) return r; - if ((r = (((int)b->status.addr) - ((int)a->status.addr)))) - return r; - if ((r = (((int)b->status.or_port) - ((int)a->status.or_port)))) - return r; - if ((r = (((int)b->status.dir_port) - ((int)a->status.dir_port)))) - return r; + + CMP_FIELD(unsigned, int, addr); + CMP_FIELD(unsigned, int, or_port); + CMP_FIELD(unsigned, int, dir_port); + return 0; }

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[tor/release-0.2.9] When examining descriptors as a dirserver, reject ones with bad versions
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit 02e05bd74dbec614397b696cfcda6525562a4675 Author: Nick Mathewson <nickm(a)torproject.org> Date: Mon Feb 13 11:18:04 2017 -0500 When examining descriptors as a dirserver, reject ones with bad versions This is an extra fix for bug 21278: it ensures that these descriptors and platforms will never be listed in a legit consensus. --- changes/bug21278_prevention | 4 ++++ src/or/dirserv.c | 10 ++++++++++ 2 files changed, 14 insertions(+) diff --git a/changes/bug21278_prevention b/changes/bug21278_prevention new file mode 100644 index 0000000..e07f0a6 --- /dev/null +++ b/changes/bug21278_prevention @@ -0,0 +1,4 @@ + o Minor features (directory authority): + - Directory authorities now reject descriptors that claim to be + malformed versions of Tor. Helps prevent exploitation of bug 21278. + diff --git a/src/or/dirserv.c b/src/or/dirserv.c index 1b614b9..fa3938b 100644 --- a/src/or/dirserv.c +++ b/src/or/dirserv.c @@ -365,6 +365,16 @@ dirserv_get_status_impl(const char *id_digest, const char *nickname, strmap_size(fingerprint_list->fp_by_name), digestmap_size(fingerprint_list->status_by_digest)); + if (platform) { + tor_version_t ver_tmp; + if (tor_version_parse_platform(platform, &ver_tmp, 1) < 0) { + if (msg) { + *msg = "Malformed platform string."; + } + return FP_REJECT; + } + } + /* Versions before Tor 0.2.4.18-rc are too old to support, and are * missing some important security fixes too. Disable them. */ if (platform && !tor_version_as_new_as(platform,"0.2.4.18-rc")) {

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[tor/release-0.2.9] Merge branch 'maint-0.2.8' into maint-0.2.9
by nickm＠torproject.org 15 Feb '17

15 Feb '17

commit eeb743588af0ec09150bd7601d553bfbabba97ac Merge: 4a2afd5 1ebdae6 Author: Nick Mathewson <nickm(a)torproject.org> Date: Wed Feb 15 07:48:10 2017 -0500 Merge branch 'maint-0.2.8' into maint-0.2.9 changes/trove-2017-001.2 | 8 ++++++++ src/or/routerparse.c | 49 +++++++++++++++++++++++++++++------------------- 2 files changed, 38 insertions(+), 19 deletions(-)

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