Wipe (some) secrets from memory after use

[tinc] / src / gcrypt / digest.c

diff --git a/src/gcrypt/digest.c b/src/gcrypt/digest.c
index 066600f..cfea1f0 100644 (file)
--- a/src/gcrypt/digest.c
+++ b/src/gcrypt/digest.c
@@ -1,6 +1,6 @@
 /*
     digest.c -- Digest handling
-    Copyright (C) 2007 Guus Sliepen <guus@tinc-vpn.org>
+    Copyright (C) 2007-2022 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -17,27 +17,26 @@
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#include "system.h"
+#include "../system.h"
 
 #include "digest.h"
-#include "logger.h"
+#include "../digest.h"
+#include "../logger.h"
 
 static struct {
        const char *name;
-       int algo;
-       int nid;
+       md_algo_t algo;
+       nid_t nid;
 } digesttable[] = {
-       {"none", GCRY_MD_NONE, 0},
-       {"sha1", GCRY_MD_SHA1, 64},
+       {"none",   GCRY_MD_NONE,   0},
+       {"sha1",   GCRY_MD_SHA1,   64},
        {"sha256", GCRY_MD_SHA256, 672},
        {"sha384", GCRY_MD_SHA384, 673},
        {"sha512", GCRY_MD_SHA512, 674},
 };
 
-static bool nametodigest(const char *name, int *algo) {
-       int i;
-
-       for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+static bool nametodigest(md_algo_t *algo, const char *name) {
+       for(size_t i = 0; i < sizeof(digesttable) / sizeof(*digesttable); i++) {
                if(digesttable[i].name && !strcasecmp(name, digesttable[i].name)) {
                        *algo = digesttable[i].algo;
                        return true;
@@ -47,10 +46,8 @@ static bool nametodigest(const char *name, int *algo) {
        return false;
 }
 
-static bool nidtodigest(int nid, int *algo) {
-       int i;
-
-       for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+static bool nidtodigest(md_algo_t *algo, nid_t nid) {
+       for(size_t i = 0; i < sizeof(digesttable) / sizeof(*digesttable); i++) {
                if(nid == digesttable[i].nid) {
                        *algo = digesttable[i].algo;
                        return true;
@@ -60,10 +57,8 @@ static bool nidtodigest(int nid, int *algo) {
        return false;
 }
 
-static bool digesttonid(int algo, int *nid) {
-       int i;
-
-       for(i = 0; i < sizeof digesttable / sizeof *digesttable; i++) {
+static bool digesttonid(nid_t *nid, md_algo_t algo) {
+       for(size_t i = 0; i < sizeof(digesttable) / sizeof(*digesttable); i++) {
                if(algo == digesttable[i].algo) {
                        *nid = digesttable[i].nid;
                        return true;
@@ -73,62 +68,68 @@ static bool digesttonid(int algo, int *nid) {
        return false;
 }
 
-static bool digest_open(digest_t *digest, int algo, int maclength) {
-       if(!digesttonid(algo, &digest->nid)) {
-               logger(LOG_DEBUG, "Digest %d has no corresponding nid!", algo);
+static bool digest_open(digest_t *digest, md_algo_t algo, size_t maclength) {
+       if(!digesttonid(&digest->nid, algo)) {
+               logger(DEBUG_ALWAYS, LOG_DEBUG, "Digest %d has no corresponding nid!", algo);
                return false;
        }
 
        unsigned int len = gcry_md_get_algo_dlen(algo);
 
-       if(maclength > len || maclength < 0)
+       if(maclength > len) {
                digest->maclength = len;
-       else
+       } else {
                digest->maclength = maclength;
-       
+       }
+
        digest->algo = algo;
        digest->hmac = NULL;
 
        return true;
 }
 
-bool digest_open_by_name(digest_t *digest, const char *name, int maclength) {
-       int algo;
+bool digest_open_by_name(digest_t *digest, const char *name, size_t maclength) {
+       md_algo_t algo;
 
-       if(!nametodigest(name, &algo)) {
-               logger(LOG_DEBUG, "Unknown digest name '%s'!", name);
+       if(!nametodigest(&algo, name)) {
+               logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown digest name '%s'!", name);
                return false;
        }
 
        return digest_open(digest, algo, maclength);
 }
 
-bool digest_open_by_nid(digest_t *digest, int nid, int maclength) {
-       int algo;
+bool digest_open_by_nid(digest_t *digest, nid_t nid, size_t maclength) {
+       md_algo_t algo;
 
-       if(!nidtodigest(nid, &algo)) {
-               logger(LOG_DEBUG, "Unknown digest ID %d!", nid);
+       if(!nidtodigest(&algo, nid)) {
+               logger(DEBUG_ALWAYS, LOG_DEBUG, "Unknown digest ID %d!", nid);
                return false;
        }
 
        return digest_open(digest, algo, maclength);
 }
 
-bool digest_open_sha1(digest_t *digest, int maclength) {
-       return digest_open(digest, GCRY_MD_SHA1, maclength);
-}
-
 void digest_close(digest_t *digest) {
-       if(digest->hmac)
+       if(!digest) {
+               return;
+       }
+
+       if(digest->hmac) {
                gcry_md_close(digest->hmac);
-       digest->hmac = NULL;
+       }
+
+       memset(digest, 0, sizeof(*digest));
 }
 
 bool digest_set_key(digest_t *digest, const void *key, size_t len) {
-       if(!digest->hmac)
+       if(!digest->hmac) {
                gcry_md_open(&digest->hmac, digest->algo, GCRY_MD_FLAG_HMAC);
-       if(!digest->hmac)
+       }
+
+       if(!digest->hmac) {
                return false;
+       }
 
        return !gcry_md_setkey(digest->hmac, key, len);
 }
@@ -137,12 +138,15 @@ bool digest_create(digest_t *digest, const void *indata, size_t inlen, void *out
        unsigned int len = gcry_md_get_algo_dlen(digest->algo);
 
        if(digest->hmac) {
-               char *tmpdata;
+               uint8_t *tmpdata;
                gcry_md_reset(digest->hmac);
                gcry_md_write(digest->hmac, indata, inlen);
                tmpdata = gcry_md_read(digest->hmac, digest->algo);
-               if(!tmpdata)
+
+               if(!tmpdata) {
                        return false;
+               }
+
                memcpy(outdata, tmpdata, digest->maclength);
        } else {
                char tmpdata[len];
@@ -154,20 +158,28 @@ bool digest_create(digest_t *digest, const void *indata, size_t inlen, void *out
 }
 
 bool digest_verify(digest_t *digest, const void *indata, size_t inlen, const void *cmpdata) {
-       unsigned int len = digest->maclength;
-       char outdata[len];
+       size_t len = digest->maclength;
+       uint8_t outdata[len];
 
        return digest_create(digest, indata, inlen, outdata) && !memcmp(cmpdata, outdata, len);
 }
 
-int digest_get_nid(const digest_t *digest) {
+nid_t digest_get_nid(const digest_t *digest) {
+       if(!digest || !digest->nid) {
+               return 0;
+       }
+
        return digest->nid;
 }
 
 size_t digest_length(const digest_t *digest) {
+       if(!digest) {
+               return 0;
+       }
+
        return digest->maclength;
 }
 
 bool digest_active(const digest_t *digest) {
-       return digest->algo != GCRY_MD_NONE;
+       return digest && digest->algo != GCRY_MD_NONE;
 }