#include <openssl/rc4.h>
#include <openssl/pem.h>
#include <openssl/sha.h>
+#include <openssl/bn.h>
#include "para.h"
#include "error.h"
return pkey;
}
+static int get_openssl_key(const char *key_file, RSA **rsa, int private)
+{
+ EVP_PKEY *key = load_key(key_file, private);
+
+ if (!key)
+ return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY
+ : -E_PUBLIC_KEY;
+ *rsa = EVP_PKEY_get1_RSA(key);
+ EVP_PKEY_free(key);
+ if (!*rsa)
+ return -E_RSA;
+ return RSA_size(*rsa);
+}
+
+#define KEY_TYPE_TXT "ssh-rsa"
+
+/* check if it is an ssh rsa key */
+static size_t is_ssh_rsa_key(char *data, size_t size)
+{
+ char *cp;
+
+ if (size < strlen(KEY_TYPE_TXT) + 2)
+ return 0;
+ cp = memchr(data, ' ', size);
+ if (cp == NULL)
+ return 0;
+ if (strncmp(KEY_TYPE_TXT, data, strlen(KEY_TYPE_TXT)))
+ return 0;
+ cp++;
+ if (cp >= data + size)
+ return 0;
+ if (*cp == '\0')
+ return 0;
+ return cp - data;
+}
+
+/*
+ * This base64/uudecode stuff below is taken from openssh-5.2p1, Copyright (c)
+ * 1996 by Internet Software Consortium. Portions Copyright (c) 1995 by
+ * International Business Machines, Inc.
+ */
+
+static const char Base64[] =
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+static const char Pad64 = '=';
+/*
+ * Skips all whitespace anywhere. Converts characters, four at a time, starting
+ * at (or after) src from base - 64 numbers into three 8 bit bytes in the
+ * target area. it returns the number of data bytes stored at the target, or -1
+ * on error.
+ */
+static int base64_decode(char const *src, unsigned char *target, size_t targsize)
+{
+ unsigned int tarindex, state;
+ int ch;
+ char *pos;
+
+ state = 0;
+ tarindex = 0;
+
+ while ((ch = *src++) != '\0') {
+ if (para_isspace(ch)) /* Skip whitespace anywhere. */
+ continue;
+
+ if (ch == Pad64)
+ break;
+
+ pos = strchr(Base64, ch);
+ if (pos == 0) /* A non-base64 character. */
+ return -1;
+
+ switch (state) {
+ case 0:
+ if (target) {
+ if (tarindex >= targsize)
+ return (-1);
+ target[tarindex] = (pos - Base64) << 2;
+ }
+ state = 1;
+ break;
+ case 1:
+ if (target) {
+ if (tarindex + 1 >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64) >> 4;
+ target[tarindex+1] = ((pos - Base64) & 0x0f)
+ << 4 ;
+ }
+ tarindex++;
+ state = 2;
+ break;
+ case 2:
+ if (target) {
+ if (tarindex + 1 >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64) >> 2;
+ target[tarindex+1] = ((pos - Base64) & 0x03)
+ << 6;
+ }
+ tarindex++;
+ state = 3;
+ break;
+ case 3:
+ if (target) {
+ if (tarindex >= targsize)
+ return (-1);
+ target[tarindex] |= (pos - Base64);
+ }
+ tarindex++;
+ state = 0;
+ break;
+ }
+ }
+
+ /*
+ * We are done decoding Base-64 chars. Let's see if we ended
+ * on a byte boundary, and/or with erroneous trailing characters.
+ */
+
+ if (ch == Pad64) { /* We got a pad char. */
+ ch = *src++; /* Skip it, get next. */
+ switch (state) {
+ case 0: /* Invalid = in first position */
+ case 1: /* Invalid = in second position */
+ return (-1);
+
+ case 2: /* Valid, means one byte of info */
+ /* Skip any number of spaces. */
+ for (; ch != '\0'; ch = *src++)
+ if (!isspace(ch))
+ break;
+ /* Make sure there is another trailing = sign. */
+ if (ch != Pad64)
+ return (-1);
+ ch = *src++; /* Skip the = */
+ /* Fall through to "single trailing =" case. */
+ /* FALLTHROUGH */
+
+ case 3: /* Valid, means two bytes of info */
+ /*
+ * We know this char is an =. Is there anything but
+ * whitespace after it?
+ */
+ for (; ch != '\0'; ch = *src++)
+ if (!isspace(ch))
+ return (-1);
+
+ /*
+ * Now make sure for cases 2 and 3 that the "extra"
+ * bits that slopped past the last full byte were
+ * zeros. If we don't check them, they become a
+ * subliminal channel.
+ */
+ if (target && target[tarindex] != 0)
+ return (-1);
+ }
+ } else {
+ /*
+ * We ended by seeing the end of the string. Make sure we
+ * have no partial bytes lying around.
+ */
+ if (state != 0)
+ return (-1);
+ }
+
+ return (tarindex);
+}
+
+static int uudecode(const char *src, unsigned char *target, size_t targsize)
+{
+ int len;
+ char *encoded, *p;
+
+ /* copy the 'readonly' source */
+ encoded = para_strdup(src);
+ /* skip whitespace and data */
+ for (p = encoded; *p == ' ' || *p == '\t'; p++)
+ ;
+ for (; *p != '\0' && *p != ' ' && *p != '\t'; p++)
+ ;
+ /* and remove trailing whitespace because base64_decode needs this */
+ *p = '\0';
+ len = base64_decode(encoded, target, targsize);
+ free(encoded);
+ return len >= 0? len : -E_BASE64;
+}
+
+/*
+ * The public key loading functions below were inspired by corresponding code
+ * of openssh-5.2p1, Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo,
+ * Finland. However, not much of the original code remains.
+ */
+
+
+/*
+ * Can not use the inline functions of portable_io.h here because the byte
+ * order is different.
+ */
+static uint32_t read_ssh_u32(const void *vp)
+{
+ const unsigned char *p = (const unsigned char *)vp;
+ uint32_t v;
+
+ v = (uint32_t)p[0] << 24;
+ v |= (uint32_t)p[1] << 16;
+ v |= (uint32_t)p[2] << 8;
+ v |= (uint32_t)p[3];
+
+ return v;
+}
+
+static int read_bignum(const unsigned char *buf, size_t len, BIGNUM **result)
+{
+ const unsigned char *p = buf, *end = buf + len;
+ uint32_t bnsize;
+ BIGNUM *bn;
+
+ if (p + 4 < p)
+ return -E_BIGNUM;
+ if (p + 4 > end)
+ return -E_BIGNUM;
+ bnsize = read_ssh_u32(p);
+ PARA_DEBUG_LOG("bnsize: %u\n", bnsize);
+ p += 4;
+ if (p + bnsize < p)
+ return -E_BIGNUM;
+ if (p + bnsize > end)
+ return -E_BIGNUM;
+ if (bnsize > 8192)
+ return -E_BIGNUM;
+ bn = BN_bin2bn(p, bnsize, NULL);
+ if (!bn)
+ return -E_BIGNUM;
+ *result = bn;
+ return bnsize + 4;
+}
+
+static int read_rsa_bignums(const unsigned char *blob, int blen, RSA **result)
+{
+ int ret;
+ RSA *rsa;
+ const unsigned char *p = blob, *end = blob + blen;
+ uint32_t rlen;
+
+ *result = NULL;
+ if (p + 4 > end)
+ return -E_BIGNUM;
+ rlen = read_ssh_u32(p);
+ p += 4;
+ if (p + rlen < p)
+ return -E_BIGNUM;
+ if (p + rlen > end)
+ return -E_BIGNUM;
+ if (rlen < strlen(KEY_TYPE_TXT))
+ return -E_BIGNUM;
+ PARA_DEBUG_LOG("type: %s, rlen: %d\n", p, rlen);
+ if (strncmp((char *)p, KEY_TYPE_TXT, strlen(KEY_TYPE_TXT)))
+ return -E_BIGNUM;
+ p += rlen;
+
+ rsa = RSA_new();
+ if (!rsa)
+ return -E_BIGNUM;
+ ret = read_bignum(p, end - p, &rsa->e);
+ if (ret < 0)
+ goto fail;
+ p += ret;
+ ret = read_bignum(p, end - p, &rsa->n);
+ if (ret < 0)
+ goto fail;
+ *result = rsa;
+ return 1;
+fail:
+ if (rsa)
+ RSA_free(rsa);
+ return ret;
+}
+
/**
* Read an asymmetric key from a file.
*
int get_asymmetric_key(const char *key_file, int private,
struct asymmetric_key **result)
{
- struct asymmetric_key *key;
- RSA *rsa;
- EVP_PKEY *pkey = load_key(key_file, private);
+ struct asymmetric_key *key = NULL;
+ void *map = NULL;
+ unsigned char *blob = NULL;
+ size_t map_size, blob_size;
+ int ret, ret2;
+ char *cp;
- if (!pkey)
- return (private == LOAD_PRIVATE_KEY)? -E_PRIVATE_KEY
- : -E_PUBLIC_KEY;
- rsa = EVP_PKEY_get1_RSA(pkey);
- EVP_PKEY_free(pkey);
- if (!rsa)
- return -E_RSA;
key = para_malloc(sizeof(*key));
- key->rsa = rsa;
- *result = key;
- return RSA_size(rsa);
+ if (private) {
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PRIVATE_KEY);
+ goto out;
+ }
+ ret = mmap_full_file(key_file, O_RDONLY, &map, &map_size, NULL);
+ if (ret < 0)
+ goto out;
+ ret = is_ssh_rsa_key(map, map_size);
+ if (!ret) {
+ ret = para_munmap(map, map_size);
+ map = NULL;
+ if (ret < 0)
+ goto out;
+ ret = get_openssl_key(key_file, &key->rsa, LOAD_PUBLIC_KEY);
+ goto out;
+ }
+ cp = map + ret;
+ PARA_INFO_LOG("decoding public rsa-ssh key %s\n", key_file);
+ ret = -ERRNO_TO_PARA_ERROR(EOVERFLOW);
+ if (map_size > INT_MAX / 4)
+ goto out;
+ blob_size = 2 * map_size;
+ blob = para_malloc(blob_size);
+ ret = uudecode(cp, blob, blob_size);
+ if (ret < 0)
+ goto out;
+ ret = read_rsa_bignums(blob, ret, &key->rsa);
+ if (ret < 0)
+ goto out;
+ ret = RSA_size(key->rsa);
+out:
+ ret2 = para_munmap(map, map_size);
+ if (ret >= 0 && ret2 < 0)
+ ret = ret2;
+ if (ret < 0) {
+ free(key);
+ result = NULL;
+ PARA_ERROR_LOG("key %s: %s\n", key_file, para_strerror(-ret));
+ } else
+ *result = key;
+ free(blob);
+ return ret;
}
/**
user=bar
target=~/.paraslash/server.users
- key=~/.paraslash/key.pub.$user
+ key=~/.paraslash/id_rsa.pub.$user
perms=AFS_READ,AFS_WRITE,VSS_READ,VSS_WRITE
mkdir -p ~/.paraslash
echo "user $user $key $perms" >> $target
Next, change to the "bar" account on client_host and generate the
key pair with the commands
- key=~/.paraslash/key.$LOGNAME
- mkdir -p ~/.paraslash
- (umask 077 && openssl genrsa -out $key 2048)
+ ssh-keygen -t rsa -b 2048
+ # hit enter twice to create a key with no passphrase
-para_server only needs to know the public key of the key pair just
-created. It can be extracted with
+This generates the two files id_rsa and id_rsa.pub in ~/.ssh. Note
+that paraslash can also read keys generated by the "openssl genrsa"
+command. However, since keys created with ssh-keygen can also be used
+for ssh, this method is recommended.
- pubkey=~/.paraslash/key.pub.$LOGNAME
- openssl rsa -in $key -pubout -out $pubkey
+Note that para_server refuses to use a key if it is shorter than 2048
+bits. In particular, the RSA keys of paraslash 0.3.x will not work
+with version 0.4.x. Moreover, para_client refuses to use a (private)
+key which is world-readable.
-Copy the public key just created to server_host (you may skip this step
-for a single-user setup, i.e. if foo=bar and server_host=client_host):
+para_server only needs to know the public key of the key pair just
+created. Copy this public key to server_host:
- scp $pubkey foo@server_host:.paraslash/
+ src=~/.ssh/id_rsa.pub
+ dest=.paraslash/id_rsa.pub.$LOGNAME
+ scp $src foo@server_host:$dest
Finally, tell para_client to connect to server_host:
contains in the third column the permissions needed to execute the
command.
-A new RSA key can be created with
-
- openssl genrsa -out <private_key> 2048
-
-and the public part may be extracted with
-
- openssl rsa -in <private_key> -pubout -out <public_key>
-
-Note that para_server refuses to use a key if it is shorter than 2048
-bits. In particular, the RSA keys of paraslash 0.3.x will not work
-with version 0.4.x. Moreover, para_client refuses to use a (private)
-key which is world-readable.
-
It is possible to make para_server reread the user_list file by
executing the paraslash "hup" command or by sending SIGHUP to the
PID of para_server.
projects / paraslash.git / commitdiff