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src: Use explicit_bzero() if available on the platform

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Signed-off-by: Andreas Schneider <asn@cryptomilk.org>
This commit is contained in:
Andreas Schneider 2018-02-12 14:35:55 +01:00
parent 25ff1214a4
commit ebcff9fd63
17 changed files with 48 additions and 52 deletions
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1
ConfigureChecks.cmake
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@ -144,6 +144,7 @@ endif()
check_function_exists(isblank HAVE_ISBLANK)
check_function_exists(strncpy HAVE_STRNCPY)
check_function_exists(strtoull HAVE_STRTOULL)
check_function_exists(explicit_bzero HAVE_EXPLICIT_BZERO)
if (HAVE_GLOB_H)
check_function_exists(glob HAVE_GLOB)

3
config.h.cmake
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@ -160,6 +160,9 @@
/* Define to 1 if you have the `glob' function. */
#cmakedefine HAVE_GLOB 1
/* Define to 1 if you have the `explicit_bzero' function. */
#cmakedefine HAVE_EXPLICIT_BZERO 1
/*************************** LIBRARIES ***************************/
/* Define to 1 if you have the `crypto' library (-lcrypto). */

31
include/libssh/priv.h
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@ -280,33 +280,22 @@ int ssh_connector_remove_event(ssh_connector connector);
/** Get the size of an array */
#define ARRAY_SIZE(a) (sizeof(a)/sizeof(a[0]))
#ifndef HAVE_EXPLICIT_BZERO
/*
* See http://llvm.org/bugs/show_bug.cgi?id=15495
*/
#if defined(HAVE_GCC_VOLATILE_MEMORY_PROTECTION)
/** Overwrite a string with '\0' */
# define BURN_STRING(x) do { \
if ((x) != NULL) \
memset((x), '\0', strlen((x))); __asm__ volatile("" : : "r"(&(x)) : "memory"); \
} while(0)
/** Overwrite the buffer with '\0' */
# define BURN_BUFFER(x, size) do { \
if ((x) != NULL) \
memset((x), '\0', (size)); __asm__ volatile("" : : "r"(&(x)) : "memory"); \
} while(0)
#define explicit_bzero(s, n) do { \
if ((s) != NULL) { \
memset((s), '\0', (n)); __asm__ volatile("" : : "r"(&(s)) : "memory"); \
} \
} while (0)
#else /* HAVE_GCC_VOLATILE_MEMORY_PROTECTION */
/** Overwrite a string with '\0' */
# define BURN_STRING(x) do { \
if ((x) != NULL) memset((x), '\0', strlen((x))); \
} while(0)
/** Overwrite the buffer with '\0' */
# define BURN_BUFFER(x, size) do { \
if ((x) != NULL) \
memset((x), '\0', (size)); \
} while(0)
#define explicit_bzero(s, n) do { \
memset((s), '\0', (n)); \
} while (0)
#endif /* HAVE_GCC_VOLATILE_MEMORY_PROTECTION */
#endif /* !HAVE_EXPLICIT_BZERO */
/**
* This is a hack to fix warnings. The idea is to use this everywhere that we

11
src/auth.c
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@ -1249,7 +1249,7 @@ void ssh_kbdint_free(ssh_kbdint kbd) {
n = kbd->nprompts;
if (kbd->prompts) {
for (i = 0; i < n; i++) {
BURN_STRING(kbd->prompts[i]);
explicit_bzero(kbd->prompts[i], strlen(kbd->prompts[i]));
SAFE_FREE(kbd->prompts[i]);
}
SAFE_FREE(kbd->prompts);
@ -1258,7 +1258,7 @@ void ssh_kbdint_free(ssh_kbdint kbd) {
n = kbd->nanswers;
if (kbd->answers) {
for (i = 0; i < n; i++) {
BURN_STRING(kbd->answers[i]);
explicit_bzero(kbd->answers[i], strlen(kbd->answers[i]));
SAFE_FREE(kbd->answers[i]);
}
SAFE_FREE(kbd->answers);
@ -1281,7 +1281,7 @@ void ssh_kbdint_clean(ssh_kbdint kbd) {
n = kbd->nprompts;
if (kbd->prompts) {
for (i = 0; i < n; i++) {
BURN_STRING(kbd->prompts[i]);
explicit_bzero(kbd->prompts[i], strlen(kbd->prompts[i]));
SAFE_FREE(kbd->prompts[i]);
}
SAFE_FREE(kbd->prompts);
@ -1291,7 +1291,7 @@ void ssh_kbdint_clean(ssh_kbdint kbd) {
if (kbd->answers) {
for (i = 0; i < n; i++) {
BURN_STRING(kbd->answers[i]);
explicit_bzero(kbd->answers[i], strlen(kbd->answers[i]));
SAFE_FREE(kbd->answers[i]);
}
SAFE_FREE(kbd->answers);
@ -1759,7 +1759,8 @@ int ssh_userauth_kbdint_setanswer(ssh_session session, unsigned int i,
}
if (session->kbdint->answers[i]) {
BURN_STRING(session->kbdint->answers[i]);
explicit_bzero(session->kbdint->answers[i],
strlen(session->kbdint->answers[i]));
SAFE_FREE(session->kbdint->answers[i]);
}

10
src/buffer.c
View File

@ -107,10 +107,10 @@ void ssh_buffer_free(struct ssh_buffer_struct *buffer) {
if (buffer->data) {
/* burn the data */
BURN_BUFFER(buffer->data, buffer->allocated);
explicit_bzero(buffer->data, buffer->allocated);
SAFE_FREE(buffer->data);
}
BURN_BUFFER(buffer, sizeof(struct ssh_buffer_struct));
explicit_bzero(buffer, sizeof(struct ssh_buffer_struct));
SAFE_FREE(buffer);
}
@ -146,7 +146,7 @@ static int realloc_buffer(struct ssh_buffer_struct *buffer, size_t needed) {
return -1;
}
memcpy(new, buffer->data,buffer->used);
BURN_BUFFER(buffer->data, buffer->used);
explicit_bzero(buffer->data, buffer->used);
SAFE_FREE(buffer->data);
} else {
new = realloc(buffer->data, needed);
@ -177,7 +177,7 @@ static void buffer_shift(ssh_buffer buffer){
if (buffer->secure){
void *ptr = buffer->data + buffer->used;
BURN_BUFFER(ptr, burn_pos);
explicit_bzero(ptr, burn_pos);
}
buffer_verify(buffer);
@ -193,7 +193,7 @@ static void buffer_shift(ssh_buffer buffer){
int ssh_buffer_reinit(struct ssh_buffer_struct *buffer)
{
buffer_verify(buffer);
BURN_BUFFER(buffer->data, buffer->used);
explicit_bzero(buffer->data, buffer->used);
buffer->used = 0;
buffer->pos = 0;
if(buffer->allocated > 127) {

6
src/external/bcrypt_pbkdf.c vendored
View File

@ -98,8 +98,8 @@ bcrypt_hash(uint8_t *sha2pass, uint8_t *sha2salt, uint8_t *out)
}
/* zap */
BURN_BUFFER(ciphertext, sizeof(ciphertext));
BURN_BUFFER(cdata, sizeof(cdata));
explicit_bzero(ciphertext, sizeof(ciphertext));
explicit_bzero(cdata, sizeof(cdata));
ZERO_STRUCT(state);
}
@ -175,7 +175,7 @@ bcrypt_pbkdf(const char *pass, size_t passlen, const uint8_t *salt, size_t saltl
}
/* zap */
BURN_BUFFER(out, sizeof(out));
explicit_bzero(out, sizeof(out));
free(countsalt);
return 0;

4
src/libcrypto.c
View File

@ -606,7 +606,7 @@ static void aes_ctr_encrypt(struct ssh_cipher_struct *cipher, void *in, void *ou
}
static void aes_ctr_cleanup(struct ssh_cipher_struct *cipher){
BURN_BUFFER(cipher->aes_key, sizeof(*cipher->aes_key));
explicit_bzero(cipher->aes_key, sizeof(*cipher->aes_key));
SAFE_FREE(cipher->aes_key);
}
@ -695,7 +695,7 @@ static void des1_1_decrypt(struct ssh_cipher_struct *cipher, void *in, void *out
}
static void des_cleanup(struct ssh_cipher_struct *cipher){
BURN_BUFFER(cipher->des3_key, sizeof(*cipher->des3_key));
explicit_bzero(cipher->des3_key, sizeof(*cipher->des3_key));
SAFE_FREE(cipher->des3_key);
}

6
src/messages.c
View File

@ -554,7 +554,8 @@ void ssh_message_free(ssh_message msg){
case SSH_REQUEST_AUTH:
SAFE_FREE(msg->auth_request.username);
if (msg->auth_request.password) {
BURN_STRING(msg->auth_request.password);
explicit_bzero(msg->auth_request.password,
strlen(msg->auth_request.password));
SAFE_FREE(msg->auth_request.password);
}
ssh_key_free(msg->auth_request.pubkey);
@ -973,7 +974,8 @@ SSH_PACKET_CALLBACK(ssh_packet_userauth_info_response){
uint32_t n;
for (n = 0; n < session->kbdint->nanswers; n++) {
BURN_STRING(session->kbdint->answers[n]);
explicit_bzero(session->kbdint->answers[n],
strlen(session->kbdint->answers[n]));
SAFE_FREE(session->kbdint->answers[n]);
}
SAFE_FREE(session->kbdint->answers);

4
src/packet_crypt.c
View File

@ -75,7 +75,7 @@ int ssh_packet_decrypt(ssh_session session, void *data,uint32_t len) {
crypto->decrypt(crypto,data,out,len);
memcpy(data,out,len);
BURN_BUFFER(out, len);
explicit_bzero(out, len);
SAFE_FREE(out);
return 0;
}
@ -127,7 +127,7 @@ unsigned char *ssh_packet_encrypt(ssh_session session, void *data, uint32_t len)
crypto->encrypt(crypto, data, out, len);
memcpy(data, out, len);
BURN_BUFFER(out, len);
explicit_bzero(out, len);
SAFE_FREE(out);
if (session->version == 2) {

2
src/pki.c
View File

@ -150,7 +150,7 @@ void ssh_key_clean (ssh_key key){
}
#endif
if (key->ed25519_privkey != NULL){
BURN_BUFFER(key->ed25519_privkey, sizeof(ed25519_privkey));
explicit_bzero(key->ed25519_privkey, sizeof(ed25519_privkey));
SAFE_FREE(key->ed25519_privkey);
}
SAFE_FREE(key->ed25519_pubkey);

8
src/pki_container_openssh.c
View File

@ -256,7 +256,7 @@ static int pki_private_key_decrypt(ssh_string blob,
if (rc < 0){
return SSH_ERROR;
}
BURN_BUFFER(passphrase_buffer, sizeof(passphrase_buffer));
explicit_bzero(passphrase_buffer, sizeof(passphrase_buffer));
cipher.set_decrypt_key(&cipher,
key_material,
@ -547,7 +547,7 @@ static int pki_private_key_encrypt(ssh_buffer privkey_buffer,
ssh_buffer_get(privkey_buffer),
ssh_buffer_get_len(privkey_buffer));
ssh_cipher_clear(&cipher);
BURN_BUFFER(passphrase_buffer, sizeof(passphrase_buffer));
explicit_bzero(passphrase_buffer, sizeof(passphrase_buffer));
return SSH_OK;
}
@ -691,7 +691,7 @@ ssh_string ssh_pki_openssh_privkey_export(const ssh_key privkey,
"\n",
OPENSSH_HEADER_END,
"\n");
BURN_BUFFER(b64, strlen((char *)b64));
explicit_bzero(b64, strlen((char *)b64));
SAFE_FREE(b64);
if (rc != SSH_OK){
@ -713,7 +713,7 @@ ssh_string ssh_pki_openssh_privkey_export(const ssh_key privkey,
error:
if (privkey_buffer != NULL) {
void *bufptr = ssh_buffer_get(privkey_buffer);
BURN_BUFFER(bufptr, ssh_buffer_get_len(privkey_buffer));
explicit_bzero(bufptr, ssh_buffer_get_len(privkey_buffer));
ssh_buffer_free(privkey_buffer);
}
SAFE_FREE(pubkey_s);

2
src/pki_crypto.c
View File

@ -1434,7 +1434,7 @@ static ssh_signature pki_signature_from_rsa_blob(const ssh_key pubkey,
blob_orig = (char *) ssh_string_data(sig_blob);
/* front-pad the buffer with zeroes */
BURN_BUFFER(blob_padded_data, pad_len);
explicit_bzero(blob_padded_data, pad_len);
/* fill the rest with the actual signature blob */
memcpy(blob_padded_data + pad_len, blob_orig, len);

4
src/pki_ed25519.c
View File

@ -132,8 +132,8 @@ int pki_ed25519_verify(const ssh_key pubkey,
hlen + ED25519_SIG_LEN,
*pubkey->ed25519_pubkey);
BURN_BUFFER(buffer, hlen + ED25519_SIG_LEN);
BURN_BUFFER(buffer2, hlen);
explicit_bzero(buffer, hlen + ED25519_SIG_LEN);
explicit_bzero(buffer2, hlen);
SAFE_FREE(buffer);
SAFE_FREE(buffer2);
if (rc == 0) {

2
src/pki_mbedcrypto.c
View File

@ -832,7 +832,7 @@ static ssh_signature pki_signature_from_rsa_blob(const ssh_key pubkey, const
blob_padded_data = (char *) ssh_string_data(sig_blob_padded);
blob_orig = (char *) ssh_string_data(sig_blob);
BURN_BUFFER(blob_padded_data, pad_len);
explicit_bzero(blob_padded_data, pad_len);
memcpy(blob_padded_data + pad_len, blob_orig, len);
sig->rsa_sig = sig_blob_padded;

2
src/session.c
View File

@ -307,7 +307,7 @@ void ssh_free(ssh_session session) {
}
/* burn connection, it could contain sensitive data */
BURN_BUFFER(session, sizeof(struct ssh_session_struct));
explicit_bzero(session, sizeof(struct ssh_session_struct));
SAFE_FREE(session);
}

2
src/string.c
View File

@ -246,7 +246,7 @@ void ssh_string_burn(struct ssh_string_struct *s) {
return;
}
BURN_BUFFER(s->data, ssh_string_len(s));
explicit_bzero(s->data, ssh_string_len(s));
}
/**

2
src/wrapper.c
View File

@ -214,7 +214,7 @@ void crypto_free(struct ssh_crypto_struct *crypto){
SAFE_FREE(crypto->kex_methods[i]);
}
BURN_BUFFER(crypto, sizeof(struct ssh_crypto_struct));
explicit_bzero(crypto, sizeof(struct ssh_crypto_struct));
SAFE_FREE(crypto);
}