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comparison libtomcrypt/src/mac/hmac/hmac_file.c @ 285:1b9e69c058d2

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propagate from branch 'au.asn.ucc.matt.ltc.dropbear' (head 20dccfc09627970a312d77fb41dc2970b62689c3) to branch 'au.asn.ucc.matt.dropbear' (head fdf4a7a3b97ae5046139915de7e40399cceb2c01)
author Matt Johnston <matt@ucc.asn.au>
date Wed, 08 Mar 2006 13:23:58 +0000
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children 0cbe8f6dbf9e
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281:997e6f7dc01e 285:1b9e69c058d2
1 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
2 *
3 * LibTomCrypt is a library that provides various cryptographic
4 * algorithms in a highly modular and flexible manner.
5 *
6 * The library is free for all purposes without any express
7 * guarantee it works.
8 *
9 * Tom St Denis, [email protected], http://libtomcrypt.org
10 */
11 #include "tomcrypt.h"
12
13 /**
14 @file hmac_file.c
15 HMAC support, process a file, Tom St Denis/Dobes Vandermeer
16 */
17
18 #ifdef HMAC
19
20 /**
21 HMAC a file
22 @param hash The index of the hash you wish to use
23 @param fname The name of the file you wish to HMAC
24 @param key The secret key
25 @param keylen The length of the secret key
26 @param out [out] The HMAC authentication tag
27 @param outlen [in/out] The max size and resulting size of the authentication tag
28 @return CRYPT_OK if successful, CRYPT_NOP if file support has been disabled
29 */
30 int hmac_file(int hash, const char *fname,
31 const unsigned char *key, unsigned long keylen,
32 unsigned char *out, unsigned long *outlen)
33 {
34 #ifdef LTC_NO_FILE
35 return CRYPT_NOP;
36 #else
37 hmac_state hmac;
38 FILE *in;
39 unsigned char buf[512];
40 size_t x;
41 int err;
42
43 LTC_ARGCHK(fname != NULL);
44 LTC_ARGCHK(key != NULL);
45 LTC_ARGCHK(out != NULL);
46 LTC_ARGCHK(outlen != NULL);
47
48 if((err = hash_is_valid(hash)) != CRYPT_OK) {
49 return err;
50 }
51
52 if ((err = hmac_init(&hmac, hash, key, keylen)) != CRYPT_OK) {
53 return err;
54 }
55
56 in = fopen(fname, "rb");
57 if (in == NULL) {
58 return CRYPT_FILE_NOTFOUND;
59 }
60
61 /* process the file contents */
62 do {
63 x = fread(buf, 1, sizeof(buf), in);
64 if ((err = hmac_process(&hmac, buf, (unsigned long)x)) != CRYPT_OK) {
65 /* we don't trap this error since we're already returning an error! */
66 fclose(in);
67 return err;
68 }
69 } while (x == sizeof(buf));
70
71 if (fclose(in) != 0) {
72 return CRYPT_ERROR;
73 }
74
75 /* get final hmac */
76 if ((err = hmac_done(&hmac, out, outlen)) != CRYPT_OK) {
77 return err;
78 }
79
80 #ifdef LTC_CLEAN_STACK
81 /* clear memory */
82 zeromem(buf, sizeof(buf));
83 #endif
84 return CRYPT_OK;
85 #endif
86 }
87
88 #endif
89
90
91 /* $Source: /cvs/libtom/libtomcrypt/src/mac/hmac/hmac_file.c,v $ */
92 /* $Revision: 1.3 $ */
93 /* $Date: 2005/05/05 14:35:58 $ */