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Merge pull request #10809 from aidangarske/fenrir-6558-nameconstraints-minmax

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Reject name constraint subtree with non-zero minimum or maximum
This commit is contained in:
Daniel Pouzzner
2026-07-01 17:38:28 -05:00
committed by GitHub
parent fed8d6a57e 2124a1075f
commit 22b552c668
2 changed files with 110 additions and 1 deletions
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tests/api.c
+96
View File
@@ -23187,6 +23187,47 @@ static word32 build_simple_nameConstraints(byte* out, word32 outSz,
XMEMCPY(out + 8, val, vlen);
return n1 + 2;
}
/* Build a NameConstraints extension value with a single subtree ([0]
* permitted or [1] excluded) whose GeneralSubtree carries a base GeneralName
* of context tag `gnTag` plus optional minimum ([0]) and maximum ([1])
* BaseDistance fields. Used to confirm that a non-zero minimum or any
* maximum is rejected (RFC 5280 4.2.1.10 requires minimum 0, maximum absent
* within this profile). */
static word32 build_minmax_nameConstraints(byte* out, word32 outSz,
int excluded, byte gnTag, const char* val, int minPresent, byte minVal,
int maxPresent, byte maxVal)
{
word32 vlen = (word32)XSTRLEN(val);
word32 extra = (word32)((minPresent ? 3 : 0) + (maxPresent ? 3 : 0));
word32 n3 = vlen + 2 + extra; /* GeneralSubtree content: base GN + min/max */
word32 n2 = n3 + 2; /* subtrees list content: one GeneralSubtree */
word32 n1 = n2 + 2; /* SEQUENCE content: the subtrees list */
word32 idx;
if (vlen > 0x7F || n3 > 0x7F || outSz < n1 + 2)
return 0;
out[0] = 0x30; /* SEQUENCE */
out[1] = (byte)n1;
out[2] = excluded ? 0xA1 : 0xA0; /* [1] excluded / [0] permitted */
out[3] = (byte)n2;
out[4] = 0x30; /* GeneralSubtree */
out[5] = (byte)n3;
out[6] = gnTag; /* base GeneralName */
out[7] = (byte)vlen;
XMEMCPY(out + 8, val, vlen);
idx = 8 + vlen;
if (minPresent) {
out[idx++] = 0x80; /* [0] minimum BaseDistance */
out[idx++] = 0x01;
out[idx++] = minVal;
}
if (maxPresent) {
out[idx++] = 0x81; /* [1] maximum BaseDistance */
out[idx++] = 0x01;
out[idx++] = maxVal;
}
return n1 + 2;
}
#endif
/* End-to-end enforcement of DNS and URI nameConstraints against wildcard and
@@ -23348,6 +23389,60 @@ static int test_NameConstraints_DnsUriWildcard(void)
return EXPECT_RESULT();
}
/* A GeneralSubtree's minimum/maximum BaseDistance fields were parsed but
* never stored or checked, so a subtree carrying a non-zero minimum or any
* maximum was silently accepted and then enforced as if it were minimum 0 /
* maximum absent. RFC 5280 4.2.1.10 requires minimum 0 and maximum absent
* within this profile, so such a constraint must be rejected. The bad
* constraint rides on the issuing CA, so a rejection surfaces as a failure
* to build the chain rather than a specific leaf error code. */
static int test_NameConstraints_SubtreeMinMax(void)
{
EXPECT_DECLS;
#if defined(WOLFSSL_ASN_TEMPLATE) && \
defined(WOLFSSL_CERT_REQ) && !defined(NO_ASN_TIME) && \
defined(WOLFSSL_CERT_GEN) && defined(HAVE_ECC) && \
defined(WOLFSSL_CERT_EXT) && !defined(NO_CERTS) && \
defined(WOLFSSL_ALT_NAMES) && defined(WOLFSSL_CUSTOM_OID) && \
defined(HAVE_OID_ENCODING) && !defined(IGNORE_NAME_CONSTRAINTS)
byte nc[64];
word32 ncSz;
const byte DNS = 0x82; /* [2] dnsName */
/* (1) Control: minimum and maximum both absent -> conformant, accepts. */
ncSz = build_minmax_nameConstraints(nc, sizeof(nc), 1, DNS, "example.com",
0, 0, 0, 0);
ExpectIntGT((int)ncSz, 0);
ExpectIntEQ(verify_with_otherName_chain(nc, ncSz, 1, NULL, 0), 0);
/* (2) Control: explicit minimum == 0 is conformant -> accepts. Pins the
* rejection below to a non-zero minimum, not to any minimum field. */
ncSz = build_minmax_nameConstraints(nc, sizeof(nc), 1, DNS, "example.com",
1, 0, 0, 0);
ExpectIntGT((int)ncSz, 0);
ExpectIntEQ(verify_with_otherName_chain(nc, ncSz, 1, NULL, 0), 0);
/* (3) minimum == 1 must be rejected. */
ncSz = build_minmax_nameConstraints(nc, sizeof(nc), 1, DNS, "example.com",
1, 1, 0, 0);
ExpectIntGT((int)ncSz, 0);
ExpectIntNE(verify_with_otherName_chain(nc, ncSz, 1, NULL, 0), 0);
/* (4) maximum present (== 0) must be rejected. */
ncSz = build_minmax_nameConstraints(nc, sizeof(nc), 1, DNS, "example.com",
0, 0, 1, 0);
ExpectIntGT((int)ncSz, 0);
ExpectIntNE(verify_with_otherName_chain(nc, ncSz, 1, NULL, 0), 0);
/* (5) maximum present (== 5) must be rejected. */
ncSz = build_minmax_nameConstraints(nc, sizeof(nc), 0, DNS, "example.com",
0, 0, 1, 5);
ExpectIntGT((int)ncSz, 0);
ExpectIntNE(verify_with_otherName_chain(nc, ncSz, 1, NULL, 0), 0);
#endif
return EXPECT_RESULT();
}
static int test_MakeCertWithCaFalse(void)
{
EXPECT_DECLS;
@@ -34967,6 +35062,7 @@ TEST_CASE testCases[] = {
TEST_DECL(test_PathLenNoKeyUsage),
TEST_DECL(test_NameConstraints_OtherName),
TEST_DECL(test_NameConstraints_DnsUriWildcard),
TEST_DECL(test_NameConstraints_SubtreeMinMax),
TEST_DECL(test_ParseSerial0FixtureMatrix),
TEST_DECL(test_MakeCertWithCaFalse),
#ifdef WOLFSSL_CERT_SIGN_CB
wolfcrypt/src/asn.c
+14 -1
View File
@@ -20537,7 +20537,20 @@ static int DecodeSubtree(const byte* input, word32 sz, Base_entry** head,
ret = GetASN_Items(subTreeASN, dataASN, subTreeASN_Length, 0, input,
&idx, sz);
if (ret == 0) {
byte t = dataASN[SUBTREEASN_IDX_BASE].tag;
byte t;
/* RFC 5280 Sec. 4.2.1.10: within this profile minimum must be 0
* and maximum must be absent. Reject a subtree that carries a
* non-zero minimum or any maximum rather than enforcing it as if
* those fields were the defaults. */
if ((minVal != 0) ||
(dataASN[SUBTREEASN_IDX_MAX].length > 0)) {
WOLFSSL_MSG("unsupported name constraint minimum/maximum");
ret = ASN_NAME_INVALID_E;
break;
}
t = dataASN[SUBTREEASN_IDX_BASE].tag;
/* Check GeneralName tag is one of the types we can handle.
* registeredID is included so that ConfirmNameConstraints can