version 1.32.2.6, 2002/03/08 17:04:41 |
version 1.33, 2000/11/14 23:42:40 |
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#include "includes.h" |
#include "includes.h" |
RCSID("$OpenBSD$"); |
RCSID("$OpenBSD$"); |
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#include <openssl/rsa.h> |
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#include <openssl/md5.h> |
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#include "rsa.h" |
#include "rsa.h" |
#include "packet.h" |
#include "packet.h" |
#include "xmalloc.h" |
#include "xmalloc.h" |
#include "ssh1.h" |
#include "ssh.h" |
#include "mpaux.h" |
#include "mpaux.h" |
#include "uidswap.h" |
#include "uidswap.h" |
#include "match.h" |
#include "match.h" |
#include "auth-options.h" |
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#include "pathnames.h" |
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#include "log.h" |
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#include "servconf.h" |
#include "servconf.h" |
#include "auth.h" |
#include "auth-options.h" |
#include "hostfile.h" |
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#include <openssl/rsa.h> |
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#include <openssl/md5.h> |
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/* import */ |
/* import */ |
extern ServerOptions options; |
extern ServerOptions options; |
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* Session identifier that is used to bind key exchange and authentication |
* Session identifier that is used to bind key exchange and authentication |
* responses to a particular session. |
* responses to a particular session. |
*/ |
*/ |
extern u_char session_id[16]; |
extern unsigned char session_id[16]; |
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/* |
/* |
* The .ssh/authorized_keys file contains public keys, one per line, in the |
* The .ssh/authorized_keys file contains public keys, one per line, in the |
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{ |
{ |
BIGNUM *challenge, *encrypted_challenge; |
BIGNUM *challenge, *encrypted_challenge; |
BN_CTX *ctx; |
BN_CTX *ctx; |
u_char buf[32], mdbuf[16], response[16]; |
unsigned char buf[32], mdbuf[16], response[16]; |
MD5_CTX md; |
MD5_CTX md; |
u_int i; |
unsigned int i; |
int len; |
int plen, len; |
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if ((encrypted_challenge = BN_new()) == NULL) |
encrypted_challenge = BN_new(); |
fatal("auth_rsa_challenge_dialog: BN_new() failed"); |
challenge = BN_new(); |
if ((challenge = BN_new()) == NULL) |
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fatal("auth_rsa_challenge_dialog: BN_new() failed"); |
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/* Generate a random challenge. */ |
/* Generate a random challenge. */ |
BN_rand(challenge, 256, 0, 0); |
BN_rand(challenge, 256, 0, 0); |
if ((ctx = BN_CTX_new()) == NULL) |
ctx = BN_CTX_new(); |
fatal("auth_rsa_challenge_dialog: BN_CTX_new() failed"); |
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BN_mod(challenge, challenge, pk->n, ctx); |
BN_mod(challenge, challenge, pk->n, ctx); |
BN_CTX_free(ctx); |
BN_CTX_free(ctx); |
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packet_write_wait(); |
packet_write_wait(); |
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/* Wait for a response. */ |
/* Wait for a response. */ |
packet_read_expect(SSH_CMSG_AUTH_RSA_RESPONSE); |
packet_read_expect(&plen, SSH_CMSG_AUTH_RSA_RESPONSE); |
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packet_integrity_check(plen, 16, SSH_CMSG_AUTH_RSA_RESPONSE); |
for (i = 0; i < 16; i++) |
for (i = 0; i < 16; i++) |
response[i] = packet_get_char(); |
response[i] = packet_get_char(); |
packet_check_eom(); |
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/* The response is MD5 of decrypted challenge plus session id. */ |
/* The response is MD5 of decrypted challenge plus session id. */ |
len = BN_num_bytes(challenge); |
len = BN_num_bytes(challenge); |
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int |
int |
auth_rsa(struct passwd *pw, BIGNUM *client_n) |
auth_rsa(struct passwd *pw, BIGNUM *client_n) |
{ |
{ |
char line[8192], *file; |
char line[8192], file[1024]; |
int authenticated; |
int authenticated; |
u_int bits; |
unsigned int bits; |
FILE *f; |
FILE *f; |
u_long linenum = 0; |
unsigned long linenum = 0; |
struct stat st; |
struct stat st; |
Key *key; |
RSA *pk; |
char *fp; |
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/* no user given */ |
/* no user given */ |
if (pw == NULL) |
if (pw == NULL) |
return 0; |
return 0; |
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/* Temporarily use the user's uid. */ |
/* Temporarily use the user's uid. */ |
temporarily_use_uid(pw); |
temporarily_use_uid(pw->pw_uid); |
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/* The authorized keys. */ |
/* The authorized keys. */ |
file = authorized_keys_file(pw); |
snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir, |
debug("trying public RSA key file %s", file); |
SSH_USER_PERMITTED_KEYS); |
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/* Fail quietly if file does not exist */ |
/* Fail quietly if file does not exist */ |
if (stat(file, &st) < 0) { |
if (stat(file, &st) < 0) { |
/* Restore the privileged uid. */ |
/* Restore the privileged uid. */ |
restore_uid(); |
restore_uid(); |
xfree(file); |
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return 0; |
return 0; |
} |
} |
/* Open the file containing the authorized keys. */ |
/* Open the file containing the authorized keys. */ |
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restore_uid(); |
restore_uid(); |
packet_send_debug("Could not open %.900s for reading.", file); |
packet_send_debug("Could not open %.900s for reading.", file); |
packet_send_debug("If your home is on an NFS volume, it may need to be world-readable."); |
packet_send_debug("If your home is on an NFS volume, it may need to be world-readable."); |
xfree(file); |
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return 0; |
return 0; |
} |
} |
if (options.strict_modes && |
if (options.strict_modes) { |
secure_filename(f, file, pw, line, sizeof(line)) != 0) { |
int fail = 0; |
xfree(file); |
char buf[1024]; |
fclose(f); |
/* Check open file in order to avoid open/stat races */ |
log("Authentication refused: %s", line); |
if (fstat(fileno(f), &st) < 0 || |
packet_send_debug("Authentication refused: %s", line); |
(st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
restore_uid(); |
(st.st_mode & 022) != 0) { |
return 0; |
snprintf(buf, sizeof buf, "RSA authentication refused for %.100s: " |
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"bad ownership or modes for '%s'.", pw->pw_name, file); |
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fail = 1; |
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} else { |
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/* Check path to SSH_USER_PERMITTED_KEYS */ |
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int i; |
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static const char *check[] = { |
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"", SSH_USER_DIR, NULL |
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}; |
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for (i = 0; check[i]; i++) { |
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snprintf(line, sizeof line, "%.500s/%.100s", pw->pw_dir, check[i]); |
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if (stat(line, &st) < 0 || |
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(st.st_uid != 0 && st.st_uid != pw->pw_uid) || |
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(st.st_mode & 022) != 0) { |
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snprintf(buf, sizeof buf, "RSA authentication refused for %.100s: " |
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"bad ownership or modes for '%s'.", pw->pw_name, line); |
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fail = 1; |
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break; |
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} |
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} |
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} |
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if (fail) { |
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fclose(f); |
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log("%s",buf); |
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packet_send_debug("%s",buf); |
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restore_uid(); |
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return 0; |
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} |
} |
} |
/* Flag indicating whether authentication has succeeded. */ |
/* Flag indicating whether authentication has succeeded. */ |
authenticated = 0; |
authenticated = 0; |
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key = key_new(KEY_RSA1); |
pk = RSA_new(); |
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pk->e = BN_new(); |
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pk->n = BN_new(); |
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/* |
/* |
* Go though the accepted keys, looking for the current key. If |
* Go though the accepted keys, looking for the current key. If |
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options = NULL; |
options = NULL; |
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/* Parse the key from the line. */ |
/* Parse the key from the line. */ |
if (hostfile_read_key(&cp, &bits, key) == 0) { |
if (!auth_rsa_read_key(&cp, &bits, pk->e, pk->n)) { |
debug("%.100s, line %lu: non ssh1 key syntax", |
debug("%.100s, line %lu: bad key syntax", |
file, linenum); |
SSH_USER_PERMITTED_KEYS, linenum); |
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packet_send_debug("%.100s, line %lu: bad key syntax", |
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SSH_USER_PERMITTED_KEYS, linenum); |
continue; |
continue; |
} |
} |
/* cp now points to the comment part. */ |
/* cp now points to the comment part. */ |
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/* Check if the we have found the desired key (identified by its modulus). */ |
/* Check if the we have found the desired key (identified by its modulus). */ |
if (BN_cmp(key->rsa->n, client_n) != 0) |
if (BN_cmp(pk->n, client_n) != 0) |
continue; |
continue; |
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/* check the real bits */ |
/* check the real bits */ |
if (bits != BN_num_bits(key->rsa->n)) |
if (bits != BN_num_bits(pk->n)) |
log("Warning: %s, line %lu: keysize mismatch: " |
log("Warning: %s, line %ld: keysize mismatch: " |
"actual %d vs. announced %d.", |
"actual %d vs. announced %d.", |
file, linenum, BN_num_bits(key->rsa->n), bits); |
file, linenum, BN_num_bits(pk->n), bits); |
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/* We have found the desired key. */ |
/* We have found the desired key. */ |
/* |
/* |
* If our options do not allow this key to be used, |
* If our options do not allow this key to be used, |
* do not send challenge. |
* do not send challenge. |
*/ |
*/ |
if (!auth_parse_options(pw, options, file, linenum)) |
if (!auth_parse_options(pw, options, linenum)) |
continue; |
continue; |
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/* Perform the challenge-response dialog for this key. */ |
/* Perform the challenge-response dialog for this key. */ |
if (!auth_rsa_challenge_dialog(key->rsa)) { |
if (!auth_rsa_challenge_dialog(pk)) { |
/* Wrong response. */ |
/* Wrong response. */ |
verbose("Wrong response to RSA authentication challenge."); |
verbose("Wrong response to RSA authentication challenge."); |
packet_send_debug("Wrong response to RSA authentication challenge."); |
packet_send_debug("Wrong response to RSA authentication challenge."); |
/* |
continue; |
* Break out of the loop. Otherwise we might send |
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* another challenge and break the protocol. |
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*/ |
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break; |
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} |
} |
/* |
/* |
* Correct response. The client has been successfully |
* Correct response. The client has been successfully |
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* otherwise continue searching. |
* otherwise continue searching. |
*/ |
*/ |
authenticated = 1; |
authenticated = 1; |
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fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); |
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verbose("Found matching %s key: %s", |
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key_type(key), fp); |
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xfree(fp); |
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break; |
break; |
} |
} |
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restore_uid(); |
restore_uid(); |
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/* Close the file. */ |
/* Close the file. */ |
xfree(file); |
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fclose(f); |
fclose(f); |
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key_free(key); |
RSA_free(pk); |
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if (authenticated) |
if (authenticated) |
packet_send_debug("RSA authentication accepted."); |
packet_send_debug("RSA authentication accepted."); |