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Fixes from review

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This commit is contained in:
Eric Blankenhorn
2026-05-08 17:15:06 -05:00
parent 29f3b30651
commit 05d73707ef
2 changed files with 24 additions and 8 deletions
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src/pk_ec.c
+10 -8
View File
@@ -1387,18 +1387,20 @@ WOLFSSL_EC_POINT* wolfSSL_EC_POINT_hex2point(const WOLFSSL_EC_GROUP *group,
}
}
else if (hex[0] == '0' && (hex[1] == '2' || hex[1] == '3')) {
size_t sz = XSTRLEN(hex + 2) / 2;
/* The SEC 1 compressed encoding is exactly 1 + key_sz bytes, so
* the hex payload after the "02"/"03" prefix is exactly 2*key_sz
* hex chars. Require an exact match: rejecting sz > key_sz keeps
* hex_to_bytes() from writing past strGx, and rejecting sz <
* key_sz keeps wolfSSL_ECPoint_d2i() from reading uninitialized
* stack bytes for the X coordinate. */
if (sz != (size_t)key_sz)
* the hex payload after the "02"/"03" prefix must be exactly
* 2*key_sz hex chars. Compare the input length directly (rather
* than XSTRLEN/2) so that odd-length inputs cannot slip past via
* integer truncation. The exact-match rejects oversized inputs
* (preventing a hex_to_bytes() write past strGx) and undersized
* inputs (preventing wolfSSL_ECPoint_d2i() from reading
* uninitialized stack bytes as the X coordinate). */
if (XSTRLEN(hex + 2) != (size_t)key_sz * 2)
goto err;
octGx[0] = (hex[1] == '2') ? ECC_POINT_COMP_EVEN
: ECC_POINT_COMP_ODD;
if (hex_to_bytes(hex + 2, octGx + 1, sz) != sz) {
if (hex_to_bytes(hex + 2, octGx + 1, (size_t)key_sz)
!= (size_t)key_sz) {
goto err;
}
if (wolfSSL_ECPoint_d2i(octGx, (word32)key_sz + 1, group, p)
tests/api/test_ossl_ec.c
+14
View File
@@ -665,6 +665,20 @@ int test_wolfSSL_EC_POINT(void)
* bytes as the X coordinate. */
ExpectNull(EC_POINT_hex2point(group, "03AB", NULL, ctx));
ExpectNull(EC_POINT_hex2point(group, "02ABCD", NULL, ctx));
/* Odd-length compressed payload: 2*key_sz + 1 hex chars after
* the "03" prefix (P-256: 65 chars). A truncating-divide bound
* (sz = XSTRLEN/2) would round down to key_sz and accept this;
* an exact-length compare must reject it. */
{
char oddLenHex[2 + 65 + 1];
for (i = 2; i < sizeof(oddLenHex) - 1; i++)
oddLenHex[i] = 'A';
oddLenHex[0] = '0';
oddLenHex[1] = '3';
oddLenHex[sizeof(oddLenHex) - 1] = '\0';
ExpectNull(EC_POINT_hex2point(group, oddLenHex, NULL, ctx));
}
}
#if defined(HAVE_COMP_KEY) && !defined(HAVE_SELFTEST)