mirror of
https://github.com/norandom/OpenUltraSAST.git
synced 2026-10-18 20:49:28 +00:00
79 lines
2.0 KiB
C
79 lines
2.0 KiB
C
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/* Provenance: openssl/openssl HKDF_Expand (fixed).
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* repo: openssl/openssl
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* commit: d12cde7fc5561d463badcd8a73079cf92864c31e
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* parent: 5d6f13d90d5c4212737002bcd54871cf236a1220
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* commit_url: https://github.com/openssl/openssl/commit/d12cde7fc5561d463badcd8a73079cf92864c31e
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* cve: CVE-2022-37454
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* license: Apache-2.0
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* function: HKDF_Expand
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* relpath: providers/implementations/kdfs/hkdf.c
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*/
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static int HKDF_Expand(const EVP_MD *evp_md,
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const unsigned char *prk, size_t prk_len,
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const unsigned char *info, size_t info_len,
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unsigned char *okm, size_t okm_len)
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{
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HMAC_CTX *hmac;
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int ret = 0, sz;
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unsigned int i;
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unsigned char prev[EVP_MAX_MD_SIZE];
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size_t done_len = 0, dig_len, n;
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sz = EVP_MD_get_size(evp_md);
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if (sz <= 0)
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return 0;
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dig_len = (size_t)sz;
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/* calc: N = ceil(L/HashLen) */
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n = okm_len / dig_len;
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if (okm_len % dig_len)
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n++;
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if (n > 255 || okm == NULL)
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return 0;
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if ((hmac = HMAC_CTX_new()) == NULL)
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return 0;
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if (!HMAC_Init_ex(hmac, prk, prk_len, evp_md, NULL))
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goto err;
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for (i = 1; i <= n; i++) {
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size_t copy_len;
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const unsigned char ctr = i;
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/* calc: T(i) = HMAC-Hash(PRK, T(i - 1) | info | i) */
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if (i > 1) {
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if (!HMAC_Init_ex(hmac, NULL, 0, NULL, NULL))
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goto err;
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if (!HMAC_Update(hmac, prev, dig_len))
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goto err;
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}
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if (!HMAC_Update(hmac, info, info_len))
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goto err;
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if (!HMAC_Update(hmac, &ctr, 1))
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goto err;
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if (!HMAC_Final(hmac, prev, NULL))
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goto err;
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copy_len = (dig_len > okm_len - done_len) ?
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okm_len - done_len :
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dig_len;
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memcpy(okm + done_len, prev, copy_len);
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done_len += copy_len;
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}
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ret = 1;
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err:
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OPENSSL_cleanse(prev, sizeof(prev));
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HMAC_CTX_free(hmac);
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return ret;
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}
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