From: Eugene Crosser <crosser@average.org>
Date: Tue, 3 Dec 2013 00:06:31 +0000 (+0400)
Subject: wip redoing authfile
X-Git-Url: http://www.average.org/gitweb/?p=pam_pcsc_cr.git;a=commitdiff_plain;h=33ff3039428415fa441fe9e2b21a854cfcb75151

wip redoing authfile
---

diff --git a/authfile.c b/authfile.c
index 83477e4..9b1313c 100644
--- a/authfile.c
+++ b/authfile.c
@@ -3,6 +3,7 @@
 #endif
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <pwd.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -11,43 +12,97 @@
 #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.
+ */
 
-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)
+static char *template = "~/.pam_cr/auth";
+
+void authfile_template(char *str)
+{
+	template = str;
+}
+
+static char *make_path(const char *tokenid, const char *userid)
+{
+	const char *usub;
+	char *path;
+	char *p, *q;
+	struct passwd *pw;
+
+	if ((p = strchr(template, '~')) != strrchr(template, '~')) return NULL;
+	if ((q = strchr(template, '?')) != strrchr(template, '?')) return NULL;
+	if (p && !userid) return NULL;
+	if (q && !tokenid) return NULL;
+	if (p == template) {
+		pw = getpwnam(userid);
+		if (!pw) return NULL;
+		usub = pw->pw_dir;
+	} else {
+		usub = userid;
+	}
+	path = malloc(strlen(template) + p?strlen(usub):0 +
+						q?strlen(tokenid):0 + 1);
+	if (!path) return NULL;
+	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';
+	return path;
+}
+
+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))
 {
-	FILE *fp;
-	int rc;
-	int i;
-	unsigned char key[20];
-	int keysize = sizeof(key);
-	unsigned char *mysecret = secret;
-	int mysecsize = secsize;
-	unsigned char *myload = payload;
-	int myloadsize = paysize;
-	unsigned char *authobj = NULL;
-	int authsize = 0;
+	struct _auth_obj ret = {0};
+	FILE *fp = NULL;
+	char *fn;
 	char *buf = NULL;
-	char *mytokenid = NULL;
-	char *myid = NULL;
-	char *mynonce = NULL;
-	char *hauthobj = NULL;
-	unsigned char *oldauthobj = NULL;
-	int oldauthsize;
-
-	if ((fp = fopen(fn, "r"))) {
+	const char *wtokenid = NULL, *wuserid = NULL, *wnonce = NULL;
+	const char *hablob = NULL;
+	unsigned char *ablob = NULL;
+	int blobsize = 0;
+	char *newnonce;
+	int nonsize;
+	struct _auth_obj ao;
+
+	if ((fn = make_path(tokenid, userid)) == NULL) {
+		ret.err = "authfile path impossible to build";
+		return ret;
+	}
+	fp = fopen(fn, "r");
+	free(fn);
+	if (fp) {
 		struct stat st;
 		int fd = fileno(fp);
 
-		if (fstat(fd, &st)) {
-			eprint("fstat \"%s\" (fd %d) error: %s",
-				fn, fd, strerror(errno));
-			st.st_size = 2047;
-		}
+		if (fstat(fd, &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)) {
@@ -55,105 +110,97 @@ int update_authfile(const char *fn, const char *tokenid, const char *id,
 
 			p = &buf[strlen(buf) - 1];
 			while (*p == '\n' || *p == '\r') *p-- = '\0';
-			mytokenid = strtok(buf, ":");
-			myid = strtok(NULL, ":");
-			mynonce = strtok(NULL, ":");
-			hauthobj = strtok(NULL, ":");
+			wtokenid = strtok(buf, ":");
+			wuserid = strtok(NULL, ":");
+			wnonce = strtok(NULL, ":");
+			hablob = strtok(NULL, ":");
 		} else {
-			eprint("error reading from %s: %s",
-				fn, strerror(errno));
+			ret.err = strerror(errno);
 		}
 		fclose(fp);
 	}
-	if (hauthobj) {
-		int hlen;
+	if (ret.err) return ret;
 
-		hlen = strlen(hauthobj);
+	if (hablob) {
+		int hlen = strlen(hablob);
 		if (hlen % 32 != 0) {
-			eprint("error: auth string has wrong length");
+			ret.err = "error: auth string has wrong length";
 		} else if (hlen !=
-				strspn(hauthobj, "0123456789abcdefABCDEF")) {
-			eprint("error: auth string not hexadecimal");
+				strspn(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(&hablob[i*2], "%2hhx", &ablob[i]);
 		}
 	}
+	if (ret.err) return ret;
 
-	if (!secret) {
-		unsigned char chal[64];
-		int csize = sizeof(chal);
-		long rc;
+	nonsize = wnonce ? strlen(wnonce)*2 : 32;
+	if (nonsize < 32) nonsize = 32;
+	newnonce = alloca(nonsize);
+	if (wnonce) strcpy(newnonce, wnonce);
+	else memset(newnonce, 0, nonsize);
+	update_nonce(newnonce, nonsize);
 
-		if (!oldauthobj || !password) {
-			eprint("if no secret given, old auth file must"
-				" be present and password must be given");
-			return -1;
-		}
-		rc = make_challenge(myid, password, mynonce, chal, &csize);
-		if (rc) {
-			eprint("cannot make challenge");
-			return -1;
-		}
-		rc = pcsc_cr(chal, csize, key, &keysize);
-		if (rc) {
-			eprint("error querying token: %s", pcsc_errstr(rc));
-			return -1;
-		}
-		mysecsize = oldauthsize;
-		mysecret = alloca(mysecsize);
-		myloadsize  = oldauthsize;
-		myload = alloca(myloadsize);
-		rc = parse_authobj(key, keysize, oldauthobj, oldauthsize,
-			mysecret, &mysecsize, myload, &myloadsize);
-		if (rc) {
-			eprint("cannot parse old authobj: %d", rc);
-			return -1;
-		}
-	}
-	if (tokenid) mytokenid = tokenid;
-	if (id) myid = id;
-	if (nonce) mynonce = nonce;
-	else {
-		unsigned int prev = atoi(mynonce);
-		mynonce = alloca(16);
-		sprintf(mynonce, "%d", prev + 1);
-	}
+	ao = authobj(userid?userid:wuserid, password,
+			wnonce, newnonce, secret, secsize,
+			payload, paylsize, ablob, blobsize,
+			fetch_key);
 
-	authsize = ((mysecsize + myloadsize + 16 + 4 * sizeof(short) - 1) /
-			16 + 1) * 16;
-	authobj = alloca(authsize);
-	rc = make_authobj(myid, password, mynonce, mysecret, mysecsize,
-			myload, myloadsize, authobj, &authsize);
-	if (rc) {
-		eprint("make_authobj error %d", rc);
-		return -1;
+	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 ((fp = fopen(fn, "w"))) {
-		if (fprintf(fp, "%s:%s:%s:", mytokenid, myid, mynonce) < 0) {
-			eprint("cannot write to \"%s\": %s",
-				fn, strerror(errno));
-			return -1;
-		}
-		for (i = 0; i < authsize; i++)
-		    if (fprintf(fp, "%02x", authobj[i]) < 0) {
-			eprint("cannot write to \"%s\": %s",
-				fn, strerror(errno));
-			return -1;
+		int i;
+
+		if (fprintf(fp, "%s:%s:%s:", tokenid?tokenid:wtokenid,
+				userid?userid:wuserid, 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);
 		}
 		fprintf(fp, "\n");
 		if (fclose(fp) < 0) {
-			eprint("cannot close \"%s\": %s",
-				fn, strerror(errno));
-			return -1;
+			ret.err = strerror(errno);
 		}
 	} else {
-		eprint("cannot open \"%s\": %s",
-			fn, strerror(errno));
-		return -1;
+		ret.err = strerror(errno);
+	}
+
+	if (!ret.err) {
+		int bufsize = (wuserid?strlen(wuserid)+1:0) + ao.paylsize;
+		if (bufsize) {
+			if ((ret.buffer = malloc(bufsize)) == NULL) {
+				ret.err = "authfile malloc failed";
+			} else {
+				unsigned char *p = ret.buffer;
+				if (wuserid) {
+					strcpy((char*)p, wuserid);
+					ret.data = p;
+					ret.datasize = strlen(wuserid)+1;
+					p += strlen(wuserid)+1;
+				}
+				if (ao.payload) {
+					memcpy(p, ao.payload, ao.paylsize);
+					ret.payload = p;
+					ret.paylsize = ao.paylsize;
+				}
+			}
+		}
 	}
-	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;
 }
diff --git a/authfile.h b/authfile.h
index 2130ce4..4a12aaa 100644
--- a/authfile.h
+++ b/authfile.h
@@ -1,11 +1,14 @@
 #ifndef _AUTHFILE_H
 #define _AUTHFILE_H
 
-int eprint(const char *format, ...);	/* must be provided by the caller */
+void authfile_template(char *template);
 
-int update_authfile(const char *fn, const char *tokenid, const char *id,
-		const char *password, const char *nonce,
+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 paysize);
+		const unsigned char *payload, const int paysize,
+		struct _auth_chunk (*fetch_key)(const unsigned char *chal,
+						const int csize));
 
 #endif