Mercurial > dropbear

annotate sk-ecdsa.c @ 1861:2b3a8026a6ce

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Add re-exec for server This allows ASLR to re-randomize the address space for every connection, preventing some vulnerabilities from being exploitable by repeated probing. Overhead (memory and time) is yet to be confirmed. At present this is only enabled on Linux. Other BSD platforms with fexecve() would probably also work though have not been tested.
author Matt Johnston <matt@ucc.asn.au>
date Sun, 30 Jan 2022 10:14:56 +0800
parents 35d504d59c05
children 333688ec53d0
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1 #include "includes.h"
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2
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3 #if DROPBEAR_SK_ECDSA
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4
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5 #include "dbutil.h"
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6 #include "ecc.h"
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7 #include "ecdsa.h"
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8 #include "sk-ecdsa.h"
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10 int buf_sk_ecdsa_verify(buffer *buf, const ecc_key *key, const buffer *data_buf, const char* app, unsigned int applen) {
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11 hash_state hs;
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12 unsigned char subhash[SHA256_HASH_SIZE];
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13 buffer *sk_buffer = NULL, *sig_buffer = NULL;
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14 unsigned char flags;
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15 unsigned int counter;
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16 int ret;
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18 TRACE(("buf_sk_ecdsa_verify"))
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20 /* from https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.u2f */
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21 /* ecdsa signature to verify (r, s) */
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22 sig_buffer = buf_getbuf(buf);
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24 flags = buf_getbyte (buf);
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25 counter = buf_getint (buf);
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26 /* create the message to be signed */
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27 sk_buffer = buf_new (2*SHA256_HASH_SIZE+5);
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28 sha256_init (&hs);
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29 sha256_process (&hs, app, applen);
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30 sha256_done (&hs, subhash);
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31 buf_putbytes (sk_buffer, subhash, sizeof (subhash));
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32 buf_putbyte (sk_buffer, flags);
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33 buf_putint (sk_buffer, counter);
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34 sha256_init (&hs);
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35 sha256_process (&hs, data_buf->data, data_buf->len);
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36 sha256_done (&hs, subhash);
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37 buf_putbytes (sk_buffer, subhash, sizeof (subhash));
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39 ret = buf_ecdsa_verify(sig_buffer, key, sk_buffer);
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40 buf_free(sk_buffer);
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41 buf_free(sig_buffer);
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43 TRACE(("leave buf_sk_ecdsa_verify, ret=%d", ret))
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44 return ret;
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45 }
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47 #endif /* DROPBEAR_SK_ECDSA */