From 07676ca03ad8afcf1ca95a2353c83fbb1d970b9b Mon Sep 17 00:00:00 2001 From: Panu Matilainen Date: Thu, 30 Sep 2021 09:59:30 +0300 Subject: [PATCH 3/3] Validate and require subkey binding signatures on PGP public keys All subkeys must be followed by a binding signature by the primary key as per the OpenPGP RFC, enforce the presence and validity in the parser. The implementation is as kludgey as they come to work around our simple-minded parser structure without touching API, to maximise backportability. Store all the raw packets internally as we decode them to be able to access previous elements at will, needed to validate ordering and access the actual data. Add testcases for manipulated keys whose import previously would succeed. Depends on the two previous commits: 7b399fcb8f52566e6f3b4327197a85facd08db91 and 236b802a4aa48711823a191d1b7f753c82a89ec5 Fixes CVE-2021-3521. Upstream-Status: Backport [https://github.com/rpm-software-management/rpm/commit/bd36c5dc9] CVE:CVE-2021-3521 Signed-off-by: Changqing Li --- rpmio/rpmpgp.c | 99 +++++++++++++++++-- tests/Makefile.am | 3 + tests/data/keys/CVE-2021-3521-badbind.asc | 25 +++++ .../data/keys/CVE-2021-3521-nosubsig-last.asc | 25 +++++ tests/data/keys/CVE-2021-3521-nosubsig.asc | 37 +++++++ tests/rpmsigdig.at | 28 ++++++ 6 files changed, 209 insertions(+), 8 deletions(-) create mode 100644 tests/data/keys/CVE-2021-3521-badbind.asc create mode 100644 tests/data/keys/CVE-2021-3521-nosubsig-last.asc create mode 100644 tests/data/keys/CVE-2021-3521-nosubsig.asc diff --git a/rpmio/rpmpgp.c b/rpmio/rpmpgp.c index 509e777e6d..371ad4d9b6 100644 --- a/rpmio/rpmpgp.c +++ b/rpmio/rpmpgp.c @@ -1061,33 +1061,116 @@ static pgpDigParams pgpDigParamsNew(uint8_t tag) return digp; } +static int hashKey(DIGEST_CTX hash, const struct pgpPkt *pkt, int exptag) +{ + int rc = -1; + if (pkt->tag == exptag) { + uint8_t head[] = { + 0x99, + (pkt->blen >> 8), + (pkt->blen ), + }; + + rpmDigestUpdate(hash, head, 3); + rpmDigestUpdate(hash, pkt->body, pkt->blen); + rc = 0; + } + return rc; +} + +static int pgpVerifySelf(pgpDigParams key, pgpDigParams selfsig, + const struct pgpPkt *all, int i) +{ + int rc = -1; + DIGEST_CTX hash = NULL; + + switch (selfsig->sigtype) { + case PGPSIGTYPE_SUBKEY_BINDING: + hash = rpmDigestInit(selfsig->hash_algo, 0); + if (hash) { + rc = hashKey(hash, &all[0], PGPTAG_PUBLIC_KEY); + if (!rc) + rc = hashKey(hash, &all[i-1], PGPTAG_PUBLIC_SUBKEY); + } + break; + default: + /* ignore types we can't handle */ + rc = 0; + break; + } + + if (hash && rc == 0) + rc = pgpVerifySignature(key, selfsig, hash); + + rpmDigestFinal(hash, NULL, NULL, 0); + + return rc; +} + int pgpPrtParams(const uint8_t * pkts, size_t pktlen, unsigned int pkttype, pgpDigParams * ret) { const uint8_t *p = pkts; const uint8_t *pend = pkts + pktlen; pgpDigParams digp = NULL; - struct pgpPkt pkt; + pgpDigParams selfsig = NULL; + int i = 0; + int alloced = 16; /* plenty for normal cases */ + struct pgpPkt *all = xmalloc(alloced * sizeof(*all)); int rc = -1; /* assume failure */ + int expect = 0; + int prevtag = 0; while (p < pend) { - if (decodePkt(p, (pend - p), &pkt)) + struct pgpPkt *pkt = &all[i]; + if (decodePkt(p, (pend - p), pkt)) break; if (digp == NULL) { - if (pkttype && pkt.tag != pkttype) { + if (pkttype && pkt->tag != pkttype) { break; } else { - digp = pgpDigParamsNew(pkt.tag); + digp = pgpDigParamsNew(pkt->tag); } } - if (pgpPrtPkt(&pkt, digp)) + if (expect) { + if (pkt->tag != expect) + break; + selfsig = pgpDigParamsNew(pkt->tag); + } + if (pgpPrtPkt(pkt, selfsig ? selfsig : digp)) break; - p += (pkt.body - pkt.head) + pkt.blen; - if (pkttype == PGPTAG_SIGNATURE) - break; + if (selfsig) { + /* subkeys must be followed by binding signature */ + if (prevtag == PGPTAG_PUBLIC_SUBKEY) { + if (selfsig->sigtype != PGPSIGTYPE_SUBKEY_BINDING) + break; + } + + int xx = pgpVerifySelf(digp, selfsig, all, i); + + selfsig = pgpDigParamsFree(selfsig); + if (xx) + break; + expect = 0; + } + + if (pkt->tag == PGPTAG_PUBLIC_SUBKEY) + expect = PGPTAG_SIGNATURE; + prevtag = pkt->tag; + + i++; + p += (pkt->body - pkt->head) + pkt->blen; + if (pkttype == PGPTAG_SIGNATURE) + break; + + if (alloced <= i) { + alloced *= 2; + all = xrealloc(all, alloced * sizeof(*all)); + } + } rc = (digp && (p == pend)) ? 0 : -1; diff --git a/tests/Makefile.am b/tests/Makefile.am index a41ce10de8..7bb23247f1 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -107,6 +107,9 @@ EXTRA_DIST += data/SPECS/hello-config-buildid.spec EXTRA_DIST += data/SPECS/hello-cd.spec EXTRA_DIST += data/keys/rpm.org-rsa-2048-test.pub EXTRA_DIST += data/keys/rpm.org-rsa-2048-test.secret +EXTRA_DIST += data/keys/CVE-2021-3521-badbind.asc +EXTRA_DIST += data/keys/CVE-2022-3521-nosubsig.asc +EXTRA_DIST += data/keys/CVE-2022-3521-nosubsig-last.asc EXTRA_DIST += data/macros.testfile EXTRA_DIST += data/macros.debug EXTRA_DIST += data/SOURCES/foo.c diff --git a/tests/data/keys/CVE-2021-3521-badbind.asc b/tests/data/keys/CVE-2021-3521-badbind.asc new file mode 100644 index 0000000000..aea00f9d7a --- /dev/null +++ b/tests/data/keys/CVE-2021-3521-badbind.asc @@ -0,0 +1,25 @@ +-----BEGIN PGP PUBLIC KEY BLOCK----- +Version: rpm-4.17.90 (NSS-3) + +mQENBFjmORgBCAC7TMEk6wnjSs8Dr4yqSScWdU2pjcqrkTxuzdWvowcIUPZI0w/g +HkRqGd4apjvY2V15kjL10gk3QhFP3pZ/9p7zh8o8NHX7aGdSGDK7NOq1eFaErPRY +91LW9RiZ0lbOjXEzIL0KHxUiTQEmdXJT43DJMFPyW9fkCWg0OltiX618FUdWWfI8 +eySdLur1utnqBvdEbCUvWK2RX3vQZQdvEBODnNk2pxqTyV0w6VPQ96W++lF/5Aas +7rUv3HIyIXxIggc8FRrnH+y9XvvHDonhTIlGnYZN4ubm9i4y3gOkrZlGTrEw7elQ +1QeMyG2QQEbze8YjpTm4iLABCBrRfPRaQpwrABEBAAG0IXJwbS5vcmcgUlNBIHRl +c3RrZXkgPHJzYUBycG0ub3JnPokBNwQTAQgAIQUCWOY5GAIbAwULCQgHAgYVCAkK +CwIEFgIDAQIeAQIXgAAKCRBDRFkeGWTF/MxxCACnjqFL+MmPh9W9JQKT2DcLbBzf +Cqo6wcEBoCOcwgRSk8dSikhARoteoa55JRJhuMyeKhhEAogE9HRmCPFdjezFTwgB +BDVBpO2dZ023mLXDVCYX3S8pShOgCP6Tn4wqCnYeAdLcGg106N4xcmgtcssJE+Pr +XzTZksbZsrTVEmL/Ym+R5w5jBfFnGk7Yw7ndwfQsfNXQb5AZynClFxnX546lcyZX +fEx3/e6ezw57WNOUK6WT+8b+EGovPkbetK/rGxNXuWaP6X4A/QUm8O98nCuHYFQq ++mvNdsCBqGf7mhaRGtpHk/JgCn5rFvArMDqLVrR9hX0LdCSsH7EGE+bR3r7wuQEN +BFjmORgBCACk+vDZrIXQuFXEYToZVwb2attzbbJJCqD71vmZTLsW0QxuPKRgbcYY +zp4K4lVBnHhFrF8MOUOxJ7kQWIJZMZFt+BDcptCYurbD2H4W2xvnWViiC+LzCMzz +iMJT6165uefL4JHTDPxC2fFiM9yrc72LmylJNkM/vepT128J5Qv0gRUaQbHiQuS6 +Dm/+WRnUfx3i89SV4mnBxb/Ta93GVqoOciWwzWSnwEnWYAvOb95JL4U7c5J5f/+c +KnQDHsW7sIiIdscsWzvgf6qs2Ra1Zrt7Fdk4+ZS2f/adagLhDO1C24sXf5XfMk5m +L0OGwZSr9m5s17VXxfspgU5ugc8kBJfzABEBAAE= +=WCfs +-----END PGP PUBLIC KEY BLOCK----- + diff --git a/tests/data/keys/CVE-2021-3521-nosubsig-last.asc b/tests/data/keys/CVE-2021-3521-nosubsig-last.asc new file mode 100644 index 0000000000..aea00f9d7a --- /dev/null +++ b/tests/data/keys/CVE-2021-3521-nosubsig-last.asc @@ -0,0 +1,25 @@ +-----BEGIN PGP PUBLIC KEY BLOCK----- +Version: rpm-4.17.90 (NSS-3) + +mQENBFjmORgBCAC7TMEk6wnjSs8Dr4yqSScWdU2pjcqrkTxuzdWvowcIUPZI0w/g +HkRqGd4apjvY2V15kjL10gk3QhFP3pZ/9p7zh8o8NHX7aGdSGDK7NOq1eFaErPRY +91LW9RiZ0lbOjXEzIL0KHxUiTQEmdXJT43DJMFPyW9fkCWg0OltiX618FUdWWfI8 +eySdLur1utnqBvdEbCUvWK2RX3vQZQdvEBODnNk2pxqTyV0w6VPQ96W++lF/5Aas +7rUv3HIyIXxIggc8FRrnH+y9XvvHDonhTIlGnYZN4ubm9i4y3gOkrZlGTrEw7elQ +1QeMyG2QQEbze8YjpTm4iLABCBrRfPRaQpwrABEBAAG0IXJwbS5vcmcgUlNBIHRl +c3RrZXkgPHJzYUBycG0ub3JnPokBNwQTAQgAIQUCWOY5GAIbAwULCQgHAgYVCAkK +CwIEFgIDAQIeAQIXgAAKCRBDRFkeGWTF/MxxCACnjqFL+MmPh9W9JQKT2DcLbBzf +Cqo6wcEBoCOcwgRSk8dSikhARoteoa55JRJhuMyeKhhEAogE9HRmCPFdjezFTwgB +BDVBpO2dZ023mLXDVCYX3S8pShOgCP6Tn4wqCnYeAdLcGg106N4xcmgtcssJE+Pr +XzTZksbZsrTVEmL/Ym+R5w5jBfFnGk7Yw7ndwfQsfNXQb5AZynClFxnX546lcyZX +fEx3/e6ezw57WNOUK6WT+8b+EGovPkbetK/rGxNXuWaP6X4A/QUm8O98nCuHYFQq ++mvNdsCBqGf7mhaRGtpHk/JgCn5rFvArMDqLVrR9hX0LdCSsH7EGE+bR3r7wuQEN +BFjmORgBCACk+vDZrIXQuFXEYToZVwb2attzbbJJCqD71vmZTLsW0QxuPKRgbcYY +zp4K4lVBnHhFrF8MOUOxJ7kQWIJZMZFt+BDcptCYurbD2H4W2xvnWViiC+LzCMzz +iMJT6165uefL4JHTDPxC2fFiM9yrc72LmylJNkM/vepT128J5Qv0gRUaQbHiQuS6 +Dm/+WRnUfx3i89SV4mnBxb/Ta93GVqoOciWwzWSnwEnWYAvOb95JL4U7c5J5f/+c +KnQDHsW7sIiIdscsWzvgf6qs2Ra1Zrt7Fdk4+ZS2f/adagLhDO1C24sXf5XfMk5m +L0OGwZSr9m5s17VXxfspgU5ugc8kBJfzABEBAAE= +=WCfs +-----END PGP PUBLIC KEY BLOCK----- + diff --git a/tests/data/keys/CVE-2021-3521-nosubsig.asc b/tests/data/keys/CVE-2021-3521-nosubsig.asc new file mode 100644 index 0000000000..3a2e7417f8 --- /dev/null +++ b/tests/data/keys/CVE-2021-3521-nosubsig.asc @@ -0,0 +1,37 @@ +-----BEGIN PGP PUBLIC KEY BLOCK----- +Version: rpm-4.17.90 (NSS-3) + +mQENBFjmORgBCAC7TMEk6wnjSs8Dr4yqSScWdU2pjcqrkTxuzdWvowcIUPZI0w/g +HkRqGd4apjvY2V15kjL10gk3QhFP3pZ/9p7zh8o8NHX7aGdSGDK7NOq1eFaErPRY +91LW9RiZ0lbOjXEzIL0KHxUiTQEmdXJT43DJMFPyW9fkCWg0OltiX618FUdWWfI8 +eySdLur1utnqBvdEbCUvWK2RX3vQZQdvEBODnNk2pxqTyV0w6VPQ96W++lF/5Aas +7rUv3HIyIXxIggc8FRrnH+y9XvvHDonhTIlGnYZN4ubm9i4y3gOkrZlGTrEw7elQ +1QeMyG2QQEbze8YjpTm4iLABCBrRfPRaQpwrABEBAAG0IXJwbS5vcmcgUlNBIHRl +c3RrZXkgPHJzYUBycG0ub3JnPokBNwQTAQgAIQUCWOY5GAIbAwULCQgHAgYVCAkK +CwIEFgIDAQIeAQIXgAAKCRBDRFkeGWTF/MxxCACnjqFL+MmPh9W9JQKT2DcLbBzf +Cqo6wcEBoCOcwgRSk8dSikhARoteoa55JRJhuMyeKhhEAogE9HRmCPFdjezFTwgB +BDVBpO2dZ023mLXDVCYX3S8pShOgCP6Tn4wqCnYeAdLcGg106N4xcmgtcssJE+Pr +XzTZksbZsrTVEmL/Ym+R5w5jBfFnGk7Yw7ndwfQsfNXQb5AZynClFxnX546lcyZX +fEx3/e6ezw57WNOUK6WT+8b+EGovPkbetK/rGxNXuWaP6X4A/QUm8O98nCuHYFQq ++mvNdsCBqGf7mhaRGtpHk/JgCn5rFvArMDqLVrR9hX0LdCSsH7EGE+bR3r7wuQEN +BFjmORgBCACk+vDZrIXQuFXEYToZVwb2attzbbJJCqD71vmZTLsW0QxuPKRgbcYY +zp4K4lVBnHhFrF8MOUOxJ7kQWIJZMZFt+BDcptCYurbD2H4W2xvnWViiC+LzCMzz +iMJT6165uefL4JHTDPxC2fFiM9yrc72LmylJNkM/vepT128J5Qv0gRUaQbHiQuS6 +Dm/+WRnUfx3i89SV4mnBxb/Ta93GVqoOciWwzWSnwEnWYAvOb95JL4U7c5J5f/+c +KnQDHsW7sIiIdscsWzvgf6qs2Ra1Zrt7Fdk4+ZS2f/adagLhDO1C24sXf5XfMk5m +L0OGwZSr9m5s17VXxfspgU5ugc8kBJfzABEBAAG5AQ0EWOY5GAEIAKT68NmshdC4 +VcRhOhlXBvZq23NtskkKoPvW+ZlMuxbRDG48pGBtxhjOngriVUGceEWsXww5Q7En +uRBYglkxkW34ENym0Ji6tsPYfhbbG+dZWKIL4vMIzPOIwlPrXrm558vgkdMM/ELZ +8WIz3KtzvYubKUk2Qz+96lPXbwnlC/SBFRpBseJC5LoOb/5ZGdR/HeLz1JXiacHF +v9Nr3cZWqg5yJbDNZKfASdZgC85v3kkvhTtzknl//5wqdAMexbuwiIh2xyxbO+B/ +qqzZFrVmu3sV2Tj5lLZ/9p1qAuEM7ULbixd/ld8yTmYvQ4bBlKv2bmzXtVfF+ymB +Tm6BzyQEl/MAEQEAAYkBHwQYAQgACQUCWOY5GAIbDAAKCRBDRFkeGWTF/PANB/9j +mifmj6z/EPe0PJFhrpISt9PjiUQCt0IPtiL5zKAkWjHePIzyi+0kCTBF6DDLFxos +3vN4bWnVKT1kBhZAQlPqpJTg+m74JUYeDGCdNx9SK7oRllATqyu+5rncgxjWVPnQ +zu/HRPlWJwcVFYEVXYL8xzfantwQTqefjmcRmBRdA2XJITK+hGWwAmrqAWx+q5xX +Pa8wkNMxVzNS2rUKO9SoVuJ/wlUvfoShkJ/VJ5HDp3qzUqncADfdGN35TDzscngQ +gHvnMwVBfYfSCABV1hNByoZcc/kxkrWMmsd/EnIyLd1Q1baKqc3cEDuC6E6/o4yJ +E4XX4jtDmdZPreZALsiB +=rRop +-----END PGP PUBLIC KEY BLOCK----- + diff --git a/tests/rpmsigdig.at b/tests/rpmsigdig.at index 8e7c759b8f..e2d30a7f1b 100644 --- a/tests/rpmsigdig.at +++ b/tests/rpmsigdig.at @@ -2,6 +2,34 @@ AT_BANNER([RPM signatures and digests]) +AT_SETUP([rpmkeys --import invalid keys]) +AT_KEYWORDS([rpmkeys import]) +RPMDB_INIT + +AT_CHECK([ +runroot rpmkeys --import /data/keys/CVE-2021-3521-badbind.asc +], +[1], +[], +[error: /data/keys/CVE-2021-3521-badbind.asc: key 1 import failed.] +) +AT_CHECK([ +runroot rpmkeys --import /data/keys/CVE-2021-3521-nosubsig.asc +], +[1], +[], +[error: /data/keys/CVE-2021-3521-nosubsig.asc: key 1 import failed.] +) + +AT_CHECK([ +runroot rpmkeys --import /data/keys/CVE-2021-3521-nosubsig-last.asc +], +[1], +[], +[error: /data/keys/CVE-2021-3521-nosubsig-last.asc: key 1 import failed.] +) +AT_CLEANUP + # ------------------------------ # Test pre-built package verification AT_SETUP([rpmkeys -Kv 1]) -- 2.17.1