f5af8aefe
Denys Vlasenko
2025-07-06
Subject
libbb/yescrypt: shrink PBKDF2
SOURCE BUG
This commit was genuinely broken at the time (not related to our build system): libbb/yescrypt eklenirken (2025-07-06 - 2025-07-07 arasi) once unutulan kaynak dosyalari (pw_encrypt_yes.c, hash_sha256_block.c, pw_ascii64.c), ardindan 64-bit'te derlenmeyen bir 'buflen' degiskeni (alg-yescrypt-kdf.c) vardi - busybox'in kendi kodundaki gercek hatalar (e5d3a8763 ile duzeltildi)
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Commit Diff GitHub →
libbb/yescrypt/alg-sha256.c+14 -14
| @@ -77,7 +77,7 @@ HMAC_SHA256_Update(HMAC_SHA256_CTX *ctx, const void *in, size_t len) | |
| * buffer ${digest}. | |
| */ | |
| static void | |
| - | HMAC_SHA256_Final(HMAC_SHA256_CTX *ctx, uint8_t digest[32]) |
| + | HMAC_SHA256_Final(HMAC_SHA256_CTX *ctx, void *digest) |
| { | |
| /* Finish the inner SHA256 operation. */ | |
| sha256_end(&ctx->ictx, digest); /* using digest[] as scratch space */ | |
| @@ -93,8 +93,7 @@ HMAC_SHA256_Final(HMAC_SHA256_CTX *ctx, uint8_t digest[32]) | |
| * length ${Klen}, and write the result to ${digest}. | |
| */ | |
| static void | |
| - | HMAC_SHA256_Buf(const void *K, size_t Klen, const void *in, size_t len, |
| - | uint8_t digest[32]) |
| + | HMAC_SHA256_Buf(const void *K, size_t Klen, const void *in, size_t len, void *digest) |
| { | |
| HMAC_SHA256_CTX ctx; | |
| HMAC_SHA256_Init(&ctx, K, Klen); | |
| @@ -114,11 +113,6 @@ PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, | |
| { | |
| HMAC_SHA256_CTX Phctx, PShctx, hctx; | |
| size_t i; | |
| - | uint8_t U[32]; |
| - | uint8_t T[32]; |
| - | uint64_t j; |
| - | int k; |
| - | size_t clen; |
| /* Compute HMAC state after processing P. */ | |
| HMAC_SHA256_Init(&Phctx, passwd, passwdlen); | |
| @@ -128,14 +122,19 @@ PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, | |
| HMAC_SHA256_Update(&PShctx, salt, saltlen); | |
| /* Iterate through the blocks. */ | |
| - | for (i = 0; i * 32 < dkLen; i++) { |
| + | for (i = 0; dkLen != 0; i++) { |
| + | uint64_t U[32 / 8]; |
| + | uint64_t T[32 / 8]; |
| + | uint64_t j; |
| uint32_t ivec; | |
| + | size_t clen; |
| + | int k; |
| /* Generate INT(i + 1). */ | |
| ivec = SWAP_BE32((uint32_t)(i + 1)); | |
| /* Compute U_1 = PRF(P, S || INT(i)). */ | |
| - | memcpy(&hctx, &PShctx, sizeof(HMAC_SHA256_CTX)); |
| + | hctx = PShctx; |
| HMAC_SHA256_Update(&hctx, &ivec, 4); | |
| HMAC_SHA256_Final(&hctx, T); | |
| @@ -144,19 +143,20 @@ PBKDF2_SHA256(const uint8_t *passwd, size_t passwdlen, | |
| memcpy(U, T, 32); | |
| for (j = 2; j <= c; j++) { | |
| /* Compute U_j. */ | |
| - | memcpy(&hctx, &Phctx, sizeof(HMAC_SHA256_CTX)); |
| + | hctx = Phctx; |
| HMAC_SHA256_Update(&hctx, U, 32); | |
| HMAC_SHA256_Final(&hctx, U); | |
| /* ... xor U_j ... */ | |
| - | for (k = 0; k < 32; k++) |
| + | for (k = 0; k < 32 / 8; k++) |
| T[k] ^= U[k]; | |
| } | |
| } | |
| /* Copy as many bytes as necessary into buf. */ | |
| - | clen = dkLen - i * 32; |
| + | clen = dkLen; |
| if (clen > 32) | |
| clen = 32; | |
| - | memcpy(&buf[i * 32], T, clen); |
| + | buf = mempcpy(buf, T, clen); |
| + | dkLen -= clen; |
| } | |
| } | |