blob: a88148fe48ec14acd5e66f097958b6d3f88ed745 [file] [log] [blame]
Richard Marian Thomaiyar14fddef2018-07-13 23:55:56 +05301From eb28ad92a2722fd30f8114840cf2b1ade26b80ee Mon Sep 17 00:00:00 2001
2From: Limeng <Meng.Li@windriver.com>
3Date: Fri, 23 Jun 2017 11:39:04 +0800
4Subject: [PATCH] tpm:openssl-tpm-engine:parse an encrypted tpm SRK password
5 from env
6
7Before, we support reading SRK password from env TPM_SRK_PW,
8but it is a plain password and not secure.
9So, we improve it and support to get an encrypted (AES algorithm)
10SRK password from env, and then parse it. The default decrypting
11AES password and salt is set in bb file.
12When we initialize TPM, and set a SRK pw, and then we need to
13encrypt it with the same AES password and salt by AES algorithm.
14At last, we set a env as below:
15export TPM_SRK_ENC_PW=xxxxxxxx
16"xxxxxxxx" is the encrypted SRK password for libtpm.so.
17
18Signed-off-by: Meng Li <Meng.Li@windriver.com>
19---
20 e_tpm.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
21 e_tpm.h | 4 ++
22 e_tpm_err.c | 4 ++
23 3 files changed, 164 insertions(+), 1 deletion(-)
24
25diff --git a/e_tpm.c b/e_tpm.c
26index 7dcb75a..11bf74b 100644
27--- a/e_tpm.c
28+++ b/e_tpm.c
29@@ -245,6 +245,118 @@ void ENGINE_load_tpm(void)
30 ERR_clear_error();
31 }
32
33+static int tpm_decode_base64(unsigned char *indata,
34+ int in_len,
35+ unsigned char *outdata,
36+ int *out_len)
37+{
38+ int total_len, len, ret;
39+ EVP_ENCODE_CTX dctx;
40+
41+ EVP_DecodeInit(&dctx);
42+
43+ total_len = 0;
44+ ret = EVP_DecodeUpdate(&dctx, outdata, &len, indata, in_len);
45+ if (ret < 0) {
46+ TSSerr(TPM_F_TPM_DECODE_BASE64, TPM_R_DECODE_BASE64_FAILED);
47+ return 1;
48+ }
49+
50+ total_len += len;
51+ ret = EVP_DecodeFinal(&dctx, outdata, &len);
52+ if (ret < 0) {
53+ TSSerr(TPM_F_TPM_DECODE_BASE64, TPM_R_DECODE_BASE64_FAILED);
54+ return 1;
55+ }
56+ total_len += len;
57+
58+ *out_len = total_len;
59+
60+ return 0;
61+}
62+
63+static int tpm_decrypt_srk_pw(unsigned char *indata, int in_len,
64+ unsigned char *outdata,
65+ int *out_len)
66+{
67+ int dec_data_len, dec_data_lenfinal;
68+ unsigned char dec_data[256];
69+ unsigned char *aes_pw;
70+ unsigned char aes_salt[PKCS5_SALT_LEN];
71+ unsigned char key[EVP_MAX_KEY_LENGTH], iv[EVP_MAX_IV_LENGTH];
72+ const EVP_CIPHER *cipher = NULL;
73+ const EVP_MD *dgst = NULL;
74+ EVP_CIPHER_CTX *ctx = NULL;
75+
76+ if (sizeof(SRK_DEC_SALT) - 1 > PKCS5_SALT_LEN) {
77+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
78+ return 1;
79+ }
80+
81+ aes_pw = malloc(sizeof(SRK_DEC_PW) - 1);
82+ if (aes_pw == NULL) {
83+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
84+ return 1;
85+ }
86+
87+ memset(aes_salt, 0x00, sizeof(aes_salt));
88+ memcpy(aes_pw, SRK_DEC_PW, sizeof(SRK_DEC_PW) - 1);
89+ memcpy(aes_salt, SRK_DEC_SALT, sizeof(SRK_DEC_SALT) - 1);
90+
91+ cipher = EVP_get_cipherbyname("aes-128-cbc");
92+ if (cipher == NULL) {
93+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
94+ free(aes_pw);
95+ return 1;
96+ }
97+ dgst = EVP_sha256();
98+
99+ EVP_BytesToKey(cipher, dgst, aes_salt, (unsigned char *)aes_pw, sizeof(SRK_DEC_PW) - 1, 1, key, iv);
100+
101+ ctx = EVP_CIPHER_CTX_new();
102+ /* Don't set key or IV right away; we want to check lengths */
103+ if (!EVP_CipherInit_ex(ctx, cipher, NULL, NULL, NULL, 0)) {
104+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
105+ free(aes_pw);
106+ return 1;
107+ }
108+
109+ OPENSSL_assert(EVP_CIPHER_CTX_key_length(ctx) == 16);
110+ OPENSSL_assert(EVP_CIPHER_CTX_iv_length(ctx) == 16);
111+
112+ if (!EVP_CipherInit_ex(ctx, NULL, NULL, key, iv, 0)) {
113+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
114+ free(aes_pw);
115+ return 1;
116+ }
117+
118+ if (!EVP_CipherUpdate(ctx, dec_data, &dec_data_len, indata, in_len)) {
119+ /* Error */
120+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
121+ free(aes_pw);
122+ EVP_CIPHER_CTX_free(ctx);
123+ return 1;
124+ }
125+
126+ if (!EVP_CipherFinal_ex(ctx, dec_data + dec_data_len, &dec_data_lenfinal)) {
127+ /* Error */
128+ TSSerr(TPM_F_TPM_DECRYPT_SRK_PW, TPM_R_DECRYPT_SRK_PW_FAILED);
129+ free(aes_pw);
130+ EVP_CIPHER_CTX_free(ctx);
131+ return 1;
132+ }
133+
134+ dec_data_len = dec_data_len + dec_data_lenfinal;
135+
136+ memcpy(outdata, dec_data, dec_data_len);
137+ *out_len = dec_data_len;
138+
139+ free(aes_pw);
140+ EVP_CIPHER_CTX_free(ctx);
141+
142+ return 0;
143+}
144+
145 int tpm_load_srk(UI_METHOD *ui, void *cb_data)
146 {
147 TSS_RESULT result;
148@@ -305,8 +417,50 @@ int tpm_load_srk(UI_METHOD *ui, void *cb_data)
149 return 0;
150 }
151
152- srkPasswd = getenv("TPM_SRK_PW");
153+ srkPasswd = getenv("TPM_SRK_ENC_PW");
154 if (NULL != srkPasswd) {
155+ int in_len = strlen(srkPasswd);
156+ int out_len;
157+ unsigned char *out_buf;
158+
159+ if (!in_len || in_len % 4) {
160+ Tspi_Context_CloseObject(hContext, hSRK);
161+ free(auth);
162+ TSSerr(TPM_F_TPM_LOAD_SRK, TPM_R_REQUEST_FAILED);
163+ return 0;
164+ }
165+
166+ out_len = in_len * 3 / 4;
167+ out_buf = malloc(out_len);
168+ if (NULL == out_buf) {
169+ Tspi_Context_CloseObject(hContext, hSRK);
170+ free(auth);
171+ TSSerr(TPM_F_TPM_LOAD_SRK, TPM_R_REQUEST_FAILED);
172+ return 0;
173+ }
174+
175+ if (tpm_decode_base64(srkPasswd, strlen(srkPasswd),
176+ out_buf, &out_len)) {
177+ Tspi_Context_CloseObject(hContext, hSRK);
178+ free(auth);
179+ free(out_buf);
180+ TSSerr(TPM_F_TPM_LOAD_SRK, TPM_R_REQUEST_FAILED);
181+ return 0;
182+ }
183+
184+ if (tpm_decrypt_srk_pw(out_buf, out_len,
185+ auth, &authlen)) {
186+ Tspi_Context_CloseObject(hContext, hSRK);
187+ free(auth);
188+ free(out_buf);
189+ TSSerr(TPM_F_TPM_LOAD_SRK, TPM_R_REQUEST_FAILED);
190+ return 0;
191+ }
192+ secretMode = TSS_SECRET_MODE_PLAIN;
193+ free(out_buf);
194+ }
195+#ifdef TPM_SRK_PLAIN_PW
196+ else if (NULL != (srkPasswd = getenv("TPM_SRK_PW")) {
197 if (0 == strcmp(srkPasswd, "#WELLKNOWN#")) {
198 memset(auth, 0, TPM_WELL_KNOWN_KEY_LEN);
199 secretMode = TSS_SECRET_MODE_SHA1;
200@@ -319,6 +473,7 @@ int tpm_load_srk(UI_METHOD *ui, void *cb_data)
201 authlen = strlen(auth);
202 }
203 }
204+#endif
205 else {
206 if (!tpm_engine_get_auth(ui, (char *)auth, 128,
207 "SRK authorization: ", cb_data)) {
208diff --git a/e_tpm.h b/e_tpm.h
209index 6316e0b..56ff202 100644
210--- a/e_tpm.h
211+++ b/e_tpm.h
212@@ -66,6 +66,8 @@ void ERR_TSS_error(int function, int reason, char *file, int line);
213 #define TPM_F_TPM_FILL_RSA_OBJECT 116
214 #define TPM_F_TPM_ENGINE_GET_AUTH 117
215 #define TPM_F_TPM_CREATE_SRK_POLICY 118
216+#define TPM_F_TPM_DECODE_BASE64 119
217+#define TPM_F_TPM_DECRYPT_SRK_PW 120
218
219 /* Reason codes. */
220 #define TPM_R_ALREADY_LOADED 100
221@@ -96,6 +98,8 @@ void ERR_TSS_error(int function, int reason, char *file, int line);
222 #define TPM_R_ID_INVALID 125
223 #define TPM_R_UI_METHOD_FAILED 126
224 #define TPM_R_UNKNOWN_SECRET_MODE 127
225+#define TPM_R_DECODE_BASE64_FAILED 128
226+#define TPM_R_DECRYPT_SRK_PW_FAILED 129
227
228 /* structure pointed to by the RSA object's app_data pointer */
229 struct rsa_app_data
230diff --git a/e_tpm_err.c b/e_tpm_err.c
231index 25a5d0f..439e267 100644
232--- a/e_tpm_err.c
233+++ b/e_tpm_err.c
234@@ -235,6 +235,8 @@ static ERR_STRING_DATA TPM_str_functs[] = {
235 {ERR_PACK(0, TPM_F_TPM_BIND_FN, 0), "TPM_BIND_FN"},
236 {ERR_PACK(0, TPM_F_TPM_FILL_RSA_OBJECT, 0), "TPM_FILL_RSA_OBJECT"},
237 {ERR_PACK(0, TPM_F_TPM_ENGINE_GET_AUTH, 0), "TPM_ENGINE_GET_AUTH"},
238+ {ERR_PACK(0, TPM_F_TPM_DECODE_BASE64, 0), "TPM_DECODE_BASE64"},
239+ {ERR_PACK(0, TPM_F_TPM_DECRYPT_SRK_PW, 0), "TPM_DECRYPT_SRK_PW"},
240 {0, NULL}
241 };
242
243@@ -265,6 +267,8 @@ static ERR_STRING_DATA TPM_str_reasons[] = {
244 {TPM_R_FILE_READ_FAILED, "failed reading the key file"},
245 {TPM_R_ID_INVALID, "engine id doesn't match"},
246 {TPM_R_UI_METHOD_FAILED, "ui function failed"},
247+ {TPM_R_DECODE_BASE64_FAILED, "decode base64 failed"},
248+ {TPM_R_DECRYPT_SRK_PW_FAILED, "decrypt srk password failed"},
249 {0, NULL}
250 };
251
252--
2532.9.3
254