main/ca-certificates: add really the c_rehash sources

main/ca-certificates/c_rehash.c

+/* c_rehash.c - Create hash symlinks for certificates
+ * C implementation based on the original Perl and shell versions
+ *
+ * Copyright (c) 2013-2014 Timo Teräs <timo.teras@iki.fi>
+ * All rights reserved.
+ *
+ * This software is licensed under the MIT License.
+ * Full license available at: http://opensource.org/licenses/MIT
+ */
+
+#include <stdio.h>
+#include <limits.h>
+#include <string.h>
+#include <unistd.h>
+#include <dirent.h>
+#include <sys/stat.h>
+
+#include <openssl/evp.h>
+#include <openssl/pem.h>
+#include <openssl/x509.h>
+
+#define MAX_COLLISIONS	256
+#define countof(x) 	(sizeof(x) / sizeof(x[0]))
+
+#if 0
+#define DEBUG(args...) fprintf(stderr, args)
+#else
+#define DEBUG(args...)
+#endif
+
+struct entry_info {
+	struct entry_info *next;
+	char *filename;
+	unsigned short old_id;
+	unsigned char need_symlink;
+	unsigned char digest[EVP_MAX_MD_SIZE];
+};
+
+struct bucket_info {
+	struct bucket_info *next;
+	struct entry_info *first_entry, *last_entry;
+	unsigned int hash;
+	unsigned short type;
+	unsigned short num_needed;
+};
+
+enum Type {
+	TYPE_CERT = 0,
+	TYPE_CRL
+};
+
+static const char *symlink_extensions[] = { "", "r" };
+static const char *file_extensions[] = { "pem", "crt", "cer", "crl" };
+
+static int evpmdsize;
+static const EVP_MD *evpmd;
+
+static int do_hash_new = 1;
+static int do_hash_old = 0;
+static int do_remove_links = 1;
+static int do_verbose = 0;
+
+static struct bucket_info *hash_table[257];
+
+static void bit_set(unsigned char *set, unsigned bit)
+{
+	set[bit / 8] |= 1 << (bit % 8);
+}
+
+static int bit_isset(unsigned char *set, unsigned bit)
+{
+	return set[bit / 8] & (1 << (bit % 8));
+}
+
+static void add_entry(
+	int type, unsigned int hash,
+	const char *filename, const unsigned char *digest,
+	int need_symlink, unsigned short old_id)
+{
+	struct bucket_info *bi;
+	struct entry_info *ei, *found = NULL;
+	unsigned int ndx = (type + hash) % countof(hash_table);
+
+	for (bi = hash_table[ndx]; bi; bi = bi->next)
+		if (bi->type == type && bi->hash == hash)
+			break;
+	if (!bi) {
+		bi = calloc(1, sizeof(*bi));
+		if (!bi) return;
+		bi->next = hash_table[ndx];
+		bi->type = type;
+		bi->hash = hash;
+		hash_table[ndx] = bi;
+	}
+
+	for (ei = bi->first_entry; ei; ei = ei->next) {
+		if (digest && memcmp(digest, ei->digest, evpmdsize) == 0) {
+			fprintf(stderr,
+				"WARNING: Skipping duplicate certificate in file %s\n",
+				filename);
+			return;
+		}
+		if (!strcmp(filename, ei->filename)) {
+			found = ei;
+			if (!digest) break;
+		}
+	}
+	ei = found;
+	if (!ei) {
+		if (bi->num_needed >= MAX_COLLISIONS) return;
+		ei = calloc(1, sizeof(*ei));
+		if (!ei) return;
+
+		ei->old_id = ~0;
+		ei->filename = strdup(filename);
+		if (bi->last_entry) bi->last_entry->next = ei;
+		if (!bi->first_entry) bi->first_entry = ei;
+		bi->last_entry = ei;
+	}
+
+	if (old_id < ei->old_id) ei->old_id = old_id;
+	if (need_symlink && !ei->need_symlink) {
+		ei->need_symlink = 1;
+		bi->num_needed++;
+		memcpy(ei->digest, digest, evpmdsize);
+	}
+}
+
+static int handle_symlink(const char *filename, const char *fullpath)
+{
+	static char xdigit[] = {
+		 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,-1,-1,-1,-1,-1,-1,
+		-1,10,11,12,13,14,15,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+		-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
+		-1,10,11,12,13,14,15
+	};
+	char linktarget[NAME_MAX], *endptr;
+	unsigned int hash = 0;
+	unsigned char ch;
+	int i, type, id;
+	ssize_t n;
+
+	for (i = 0; i < 8; i++) {
+		ch = filename[i] - '0';
+		if (ch >= countof(xdigit) || xdigit[ch] < 0)
+			return -1;
+		hash <<= 4;
+		hash += xdigit[ch];
+	}
+	if (filename[i++] != '.') return -1;
+	for (type = countof(symlink_extensions) - 1; type > 0; type--)
+		if (strcasecmp(symlink_extensions[type], &filename[i]) == 0)
+			break;
+	i += strlen(symlink_extensions[type]);
+
+	id = strtoul(&filename[i], &endptr, 10);
+	if (*endptr != 0) return -1;
+
+	n = readlink(fullpath, linktarget, sizeof(linktarget));
+	if (n >= sizeof(linktarget) || n < 0) return -1;
+	linktarget[n] = 0;
+
+	DEBUG("Found existing symlink %s for %08x (%d), certname %s\n",
+		filename, hash, type, linktarget);
+	add_entry(type, hash, linktarget, NULL, 0, id);
+	return 0;
+}
+
+static int handle_certificate(const char *filename, const char *fullpath)
+{
+	STACK_OF(X509_INFO) *inf;
+	X509_INFO *x;
+	BIO *b;
+	const char *ext;
+	unsigned char digest[EVP_MAX_MD_SIZE];
+	X509_NAME *name = NULL;
+	int i, type, ret = -1;
+
+	ext = strrchr(filename, '.');
+	if (ext == NULL) return 0;
+	for (i = 0; i < countof(file_extensions); i++) {
+		if (strcasecmp(file_extensions[i], ext+1) == 0)
+			break;
+	}
+	if (i >= countof(file_extensions)) return -1;
+
+	b = BIO_new_file(fullpath, "r");
+	if (!b) return -1;
+	inf = PEM_X509_INFO_read_bio(b, NULL, NULL, NULL);
+	BIO_free(b);
+	if (!inf) return -1;
+
+	if (sk_X509_INFO_num(inf) == 1) {
+		x = sk_X509_INFO_value(inf, 0);
+		if (x->x509) {
+			type = TYPE_CERT;
+			name = X509_get_subject_name(x->x509);
+			X509_digest(x->x509, evpmd, digest, NULL);
+		} else if (x->crl) {
+			type = TYPE_CRL;
+			name = X509_CRL_get_issuer(x->crl);
+			X509_CRL_digest(x->crl, evpmd, digest, NULL);
+		}
+		if (name && do_hash_new)
+			add_entry(type, X509_NAME_hash(name), filename, digest, 1, ~0);
+		if (name && do_hash_old)
+			add_entry(type, X509_NAME_hash_old(name), filename, digest, 1, ~0);
+	} else {
+		fprintf(stderr,
+			"WARNING: %s does not contain exactly one certificate or CRL: skipping\n",
+			filename);
+	}
+
+	sk_X509_INFO_pop_free(inf, X509_INFO_free);
+
+	return ret;
+}
+
+static int hash_dir(const char *dirname)
+{
+	struct bucket_info *bi, *nextbi;
+	struct entry_info *ei, *nextei;
+	struct dirent *de;
+	struct stat st;
+	unsigned char idmask[MAX_COLLISIONS / 8];
+	int i, n, nextid, buflen, ret = -1;
+	const char *pathsep;
+	char *buf;
+	DIR *d;
+
+	if (access(dirname, R_OK|W_OK|X_OK) != 0) {
+		fprintf(stderr,
+			"ERROR: Access denied '%s'\n",
+			dirname);
+		return -1;
+	}
+
+	buflen = strlen(dirname);
+	pathsep = (buflen && dirname[buflen-1] == '/') ? "" : "/";
+	buflen += NAME_MAX + 2;
+	buf = malloc(buflen);
+	if (buf == NULL)
+		goto err;
+
+	if (do_verbose) printf("Doing %s\n", dirname);
+	d = opendir(dirname);
+	if (!d) goto err;
+
+	while ((de = readdir(d)) != NULL) {
+		if (snprintf(buf, buflen, "%s%s%s", dirname, pathsep, de->d_name) >= buflen)
+			continue;
+		if (lstat(buf, &st) < 0)
+			continue;
+		if (S_ISLNK(st.st_mode) && handle_symlink(de->d_name, buf) == 0)
+			continue;
+		handle_certificate(de->d_name, buf);
+	}
+	closedir(d);
+
+	for (i = 0; i < countof(hash_table); i++) {
+		for (bi = hash_table[i]; bi; bi = nextbi) {
+			nextbi = bi->next;
+			DEBUG("Type %d, hash %08x, num entries %d:\n", bi->type, bi->hash, bi->num_needed);
+
+			nextid = 0;
+			memset(idmask, 0, (bi->num_needed+7)/8);
+			for (ei = bi->first_entry; ei; ei = ei->next)
+				if (ei->old_id < bi->num_needed)
+					bit_set(idmask, ei->old_id);
+
+			for (ei = bi->first_entry; ei; ei = nextei) {
+				nextei = ei->next;
+				DEBUG("\t(old_id %d, need_symlink %d) Cert %s\n",
+					ei->old_id, ei->need_symlink,
+					ei->filename);
+
+				if (ei->old_id < bi->num_needed) {
+					/* Link exists, and is used as-is */
+					snprintf(buf, buflen, "%08x.%s%d", bi->hash, symlink_extensions[bi->type], ei->old_id);
+					if (do_verbose) printf("link %s -> %s\n", ei->filename, buf);
+				} else if (ei->need_symlink) {
+					/* New link needed (it may replace something) */
+					while (bit_isset(idmask, nextid))
+						nextid++;
+
+					snprintf(buf, buflen, "%s%s%n%08x.%s%d",
+						 dirname, pathsep, &n, bi->hash,
+						 symlink_extensions[bi->type],
+						 nextid);
+					if (do_verbose) printf("link %s -> %s\n", ei->filename, &buf[n]);
+					unlink(buf);
+					symlink(ei->filename, buf);
+				} else if (do_remove_links) {
+					/* Link to be deleted */
+					snprintf(buf, buflen, "%s%s%n%08x.%s%d",
+						 dirname, pathsep, &n, bi->hash,
+						 symlink_extensions[bi->type],
+						 ei->old_id);
+					if (do_verbose) printf("unlink %s\n", &buf[n]);
+					unlink(buf);
+				}
+				free(ei->filename);
+				free(ei);
+			}
+			free(bi);
+		}
+		hash_table[i] = NULL;
+	}
+
+	ret = 0;
+err:
+	free(buf);
+	return ret;
+}
+
+static void c_rehash_usage(void)
+{
+	printf("\
+usage: c_rehash <args> <dirs>\n\
+\n\
+-compat       - create new- and old-style hashed links\n\
+-old          - use old-style hashing for generating links\n\
+-h            - display this help\n\
+-n            - do not remove existing links\n\
+-v            - be more verbose\n\
+\n");
+}
+
+int main(int argc, char **argv)
+{
+	const char *env, *opt;
+	int i, numargs, r = 0;
+
+	evpmd = EVP_sha1();
+	evpmdsize = EVP_MD_size(evpmd);
+
+	numargs = argc;
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] != '-') continue;
+		if (strcmp(argv[i], "--") == 0) { argv[i] = 0; numargs--; break; }
+		opt = &argv[i][1];
+		if (strcmp(opt, "compat") == 0) {
+			do_hash_new = do_hash_old = 1;
+		} else if (strcmp(opt, "old") == 0) {
+			do_hash_new = 0;
+			do_hash_old = 1;
+		} else if (strcmp(opt, "n") == 0) {
+			do_remove_links = 0;
+		} else if (strcmp(opt, "v") == 0) {
+			do_verbose++;
+		} else {
+			if (strcmp(opt, "h") != 0)
+				fprintf(stderr, "unknown option %s\n", argv[i]);
+			c_rehash_usage();
+			return 1;
+		}
+		argv[i] = 0;
+		numargs--;
+	}
+
+	if (numargs > 1) {
+		for (i = 1; i < argc; i++)
+			if (argv[i]) r |= hash_dir(argv[i]);
+	} else if ((env = getenv("SSL_CERT_DIR")) != NULL) {
+		char *e, *m;
+		m = strdup(env);
+		for (e = strtok(m, ":"); e != NULL; e = strtok(NULL, ":"))
+			r |= hash_dir(e);
+		free(m);
+	} else {
+		r |= hash_dir("/etc/ssl/certs");
+	}
+
+	return r ? 2 : 0;
+}