X-Git-Url: http://www.average.org/gitweb/?p=pam_pcsc_cr.git;a=blobdiff_plain;f=authfile.c;h=c43b2d655b0a6f2ee1d7640b648b0cc0cf9f35c7;hp=1e0826d4d8396505f7da71a1f8e3c0a8dad99dd1;hb=dc50dc3cbff0a815c899828c991e17f85458631c;hpb=4a5da38dfd8b0236564ffe6b70eab1eeb399fff0

diff --git a/authfile.c b/authfile.c
index 1e0826d..c43b2d6 100644
--- a/authfile.c
+++ b/authfile.c
@@ -1,6 +1,33 @@
+/*
+Copyright (c) 2013 Eugene Crosser
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must
+    not claim that you wrote the original software. If you use this
+    software in a product, an acknowledgment in the product documentation
+    would be appreciated but is not required.
+
+    2. Altered source versions must be plainly marked as such, and must
+    not be misrepresented as being the original software.
+
+    3. This notice may not be removed or altered from any source
+    distribution.
+*/
+
 #ifdef HAVE_CONFIG_H
 # include "config.h"
 #endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <pwd.h>
+#include <time.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -9,112 +36,234 @@
 #include <alloca.h>
 #include "authobj.h"
 #include "authfile.h"
-#include "pcsc_cr.h"
 
-#define OBJSIZE 256
+/*
+ * Template string may contain zero or one '~' and zero or one '?'.
+ * '~' at the beginning of the template string is substituted with
+ * the home directory of the userid. In any other position it is
+ * substituted with the userid itself. '?' is substituted with the
+ * tokenid. There is no way to make the resulting path contain '~'
+ * or '?'. If there is more than one '~' or '?', or if the '~' is
+ * at the beginning but userid does not resolve via getpwnam, or
+ * the character to substitute is present but the argument is NULL,
+ * NULL is returned. Otherwise, malloc()'ed area containg the path
+ * string.
+ */
+
+static const char *template = "~/.pam_cr/auth";
+
+void authfile_template(const char *str)
+{
+	template = str;
+}
+
+static int path_size(const char *tokenid, const char *userid)
+{
+	const char *usub;
+	const char *p, *q;
+	struct passwd *pw;
+
+	if ((p = strchr(template, '~')) != strrchr(template, '~')) return 0;
+	if ((q = strchr(template, '?')) != strrchr(template, '?')) return 0;
+	if (p && !userid) return 0;
+	if (q && !tokenid) return 0;
+	if (p == template) {
+		pw = getpwnam(userid);
+		if (!pw) return 0;
+		usub = pw->pw_dir;
+	} else {
+		usub = userid;
+	}
+	return strlen(template)+(p?strlen(usub):0)+(q?strlen(tokenid):0)+1;
+}
+
+static void
+make_path(char * const path, const char *tokenid, const char *userid)
+{
+	const char *usub;
+	const char *p;
+	char *q;
+	struct passwd *pw;
+
+	path[0] = '\0';
+	if (template[0] == '~') {
+		pw = getpwnam(userid);
+		if (!pw) return;
+		usub = pw->pw_dir;
+	} else {
+		usub = userid;
+	}
+	q = path;
+	for (p = template; *p; p++) switch (*p) {
+	case '~':
+		strcpy(q, usub);
+		while (*q) q++;
+		break;
+	case '?':
+		strcpy(q, tokenid);
+		while (*q) q++;
+		break;
+	default:
+		*q++ = *p;
+		break;
+	}
+	*q = '\0';
+}
 
-int update_authfile(const char *fn, const char *tokenid, const char *id,
-                const char *password, const char *nonce,
-                const unsigned char *secret, const int secsize,
-                const unsigned char *payload, const int paysize)
+int parse(char * const buf, const int argc, const char *argv[const])
 {
-	FILE *fp;
-	int rc;
+	char *p, *q;
 	int i;
-	unsigned char key[20];
-	int keysize = sizeof(key);
-	unsigned char mysecret[20];
-	int mysecsize = sizeof(mysecret);
-	unsigned char myload[256];
-	int myloadsize = sizeof(myload);
-	unsigned char *authobj = alloca(OBJSIZE);
-	int authsize = OBJSIZE;
-	char buf[512];
-	char *oldtokenid = NULL, *oldid = NULL, *oldnonce = NULL,
-		*hauthobj = NULL;
-	unsigned char *oldauthobj = NULL;
-	int oldauthsize;
-
-	if ((fp = fopen(fn, "r"))) {
-		if (fgets(buf, sizeof(buf), fp)) {
-			oldtokenid = strtok(buf, ":\r\n");
-			oldid = strtok(NULL, ":\r\n");
-			oldnonce = strtok(NULL, ":\r\n");
-			hauthobj = strtok(NULL, ":\r\n");
-		} else {
-			eprint("error reading from %s: %s\n",
-				fn, strerror(errno));
+
+	for (i = 0, p = buf; *p; p = q+1, i++) {
+		for (q = p; *q && *q != ':' && *q != '\r' && *q != '\n'; q++) ;
+		*q = '\0';
+		if (*p && i < argc) argv[i] = p;
+	}
+	return i != argc;
+}
+
+struct _auth_obj authfile(const char *tokenid,
+		const char *userid, const char *password,
+		void (*update_nonce)(char *nonce, const int nonsize),
+		const unsigned char *secret, const int secsize,
+		const unsigned char *payload, const int paylsize,
+		struct _auth_chunk (*fetch_key)(const unsigned char *chal,
+						const int csize))
+{
+	struct _auth_obj ret = {0};
+	mode_t oldmask;
+	FILE *fp = NULL;
+	char *fn, *nfn;
+	int fnl;
+	struct stat st = {0};
+	char *buf = NULL;
+	struct {
+		const char *tokenid;
+		const char *userid;
+		const char *nonce;
+		const char *hablob;
+	} w = {"", NULL, NULL, NULL};
+	unsigned char *ablob = NULL;
+	int blobsize = 0;
+	char *newnonce;
+	int nonsize;
+	struct _auth_obj ao;
+
+	if ((fnl = path_size(tokenid, userid)) == 0) {
+		ret.err = "authfile path impossible to build";
+		return ret;
+	}
+	fn = alloca(fnl);
+	make_path(fn, tokenid, userid);
+	nfn = alloca(fnl+32);
+	snprintf(nfn, fnl+32, "%s.%d.%ld", fn, (int)getpid(), (long)time(NULL));
+	fp = fopen(fn, "r");
+	if (fp) {
+		if (fstat(fileno(fp), &st)) st.st_size = 2047;
+		if (st.st_size > 2047) st.st_size = 2047;
+		buf = alloca(st.st_size + 1);
+		if (!fgets(buf, st.st_size + 1, fp)) {
+			ret.err = strerror(errno);
+		} else if (parse(buf, sizeof(w)/sizeof(char*),
+					(const char ** const)&w)){
+			ret.err = "error: unparseable auth file";
 		}
 		fclose(fp);
 	}
-	if (hauthobj) {
-		int hlen;
+	if (ret.err) return ret;
 
-		hlen = strlen(hauthobj);
+	if (w.hablob) {
+		int hlen = strlen(w.hablob);
 		if (hlen % 32 != 0) {
-			eprint("error: auth string has wrong length\n");
+			ret.err = "error: auth string has wrong length";
 		} else if (hlen !=
-				strspn(hauthobj, "0123456789abcdefABCDEF")) {
-			eprint("error: auth string not hexadecimal\n");
+				strspn(w.hablob, "0123456789abcdefABCDEF")) {
+			ret.err = "error: auth string not hexadecimal";
 		} else {
-			oldauthsize = hlen/2;
-			oldauthobj = alloca(oldauthsize);
-			for (i = 0; i < oldauthsize; i++)
-				sscanf(&hauthobj[i*2], "%2hhx", &oldauthobj[i]);
+			int i;
+
+			blobsize = hlen/2;
+			ablob = alloca(blobsize);
+			for (i = 0; i < blobsize; i++)
+				sscanf(&w.hablob[i*2], "%2hhx", &ablob[i]);
 		}
 	}
+	if (ret.err) return ret;
+
+	nonsize = w.nonce ? strlen(w.nonce)*2 : 32;
+	if (nonsize < 32) nonsize = 32;
+	newnonce = alloca(nonsize);
+	if (w.nonce) strcpy(newnonce, w.nonce);
+	else memset(newnonce, 0, nonsize);
+	update_nonce(newnonce, nonsize);
+
+	ao = authobj(userid?userid:w.userid, password,
+			w.nonce, newnonce, secret, secsize,
+			payload, paylsize, ablob, blobsize,
+			fetch_key);
+
+	if (ao.err) {
+		ret.err = ao.err;
+		if (ao.data) memset(ao.data, 0, ao.datasize);
+		if (ao.payload) memset(ao.payload, 0, ao.paylsize);
+		if (ao.buffer) free(ao.buffer);
+		return ret;
+	}
 
-	if (oldauthobj && password && !secret) {
-		unsigned char chal[64];
-		int csize = sizeof(chal);
-		long rc;
+	oldmask = umask(077);
+	if ((fp = fopen(nfn, "w"))) {
+		int i;
 
-		rc = make_challenge(id, password, nonce, chal, &csize);
-		if (rc) {
-			eprint("cannot make challenge\n");
-			return -1;
+		if (fprintf(fp, "%s:%s:%s:", tokenid?tokenid:w.tokenid,
+				userid?userid:w.userid, newnonce) < 0) {
+			ret.err = strerror(errno);
+		} else for (i = 0; i < ao.datasize; i++)
+		    if (fprintf(fp, "%02x", ao.data[i]) < 0) {
+			ret.err = strerror(errno);
 		}
-		rc = pcsc_cr(chal, csize, key, &keysize);
-		if (rc) {
-			eprint("error querying token: %s\n", pcsc_errstr(rc));
-			return -1;
+		fprintf(fp, "\n");
+		if (st.st_uid || st.st_gid) {
+			if (fchown(fileno(fp), st.st_uid, st.st_gid)) /*ign*/;
 		}
-		rc = parse_authobj(key, keysize, oldauthobj, oldauthsize,
-			mysecret, &mysecsize, myload, &myloadsize);
-		if (rc) {
-			eprint("cannot parse old authobj: %d\n", rc);
-			return -1;
+		if (fclose(fp) < 0) {
+			ret.err = strerror(errno);
 		}
+	} else {
+		ret.err = strerror(errno);
 	}
-
-	rc = make_authobj(id, password, nonce, mysecret, mysecsize,
-			payload, paysize, authobj, &authsize);
-	if (rc) {
-		eprint("make_authobj error %d\n", rc);
-		return -1;
-	}
-	fp = fopen(fn, "w");
-	if (!fp) {
-		eprint("cannot open \"%s\": %s\n",
-			fn, strerror(errno));
-		return -1;
+	(void)umask(oldmask);
+	if (ret.err) {
+		unlink(nfn); /* may not exist but no matter */
+	} else if (rename(nfn, fn)) {
+		ret.err = strerror(errno);
 	}
-	if (fprintf(fp, "%s:%s:%s:", tokenid, id, nonce) < 0) {
-		eprint("cannot write to \"%s\": %s\n",
-			fn, strerror(errno));
-		return -1;
-	}
-	for (i = 0; i < authsize; i++)
-	    if (fprintf(fp, "%02x", authobj[i]) < 0) {
-		eprint("cannot write to \"%s\": %s\n",
-			fn, strerror(errno));
-		return -1;
-	}
-	fprintf(fp, "\n");
-	if (fclose(fp) < 0) {
-		eprint("cannot close \"%s\": %s\n",
-			fn, strerror(errno));
-		return -1;
+
+	if (!ret.err) {
+		int bufsize = (w.userid?strlen(w.userid)+1:0) + ao.paylsize + 1;
+		if (bufsize) {
+			if ((ret.buffer = malloc(bufsize)) == NULL) {
+				ret.err = "authfile malloc failed";
+			} else {
+				unsigned char *p = ret.buffer;
+				if (w.userid) {
+					strcpy((char*)p, w.userid);
+					ret.data = p;
+					ret.datasize = strlen(w.userid)+1;
+					p += strlen(w.userid)+1;
+				}
+				if (ao.payload) {
+					memcpy(p, ao.payload, ao.paylsize);
+					p[ao.paylsize] = '\0';
+					ret.payload = p;
+					ret.paylsize = ao.paylsize+1;
+				}
+			}
+		}
 	}
-	return 0;
+
+	if (ao.data) memset(ao.data, 0, ao.datasize);
+	if (ao.payload) memset(ao.payload, 0, ao.paylsize);
+	if (ao.buffer) free(ao.buffer);
+	return ret;
 }