X-Git-Url: http://www.average.org/gitweb/?p=pam_pcsc_cr.git;a=blobdiff_plain;f=authfile.c;h=c43b2d655b0a6f2ee1d7640b648b0cc0cf9f35c7;hp=9b1313c85ce63e6aa1964043d703bfbcd7c8fdcb;hb=dc50dc3cbff0a815c899828c991e17f85458631c;hpb=33ff3039428415fa441fe9e2b21a854cfcb75151;ds=sidebyside

diff --git a/authfile.c b/authfile.c
index 9b1313c..c43b2d6 100644
--- a/authfile.c
+++ b/authfile.c
@@ -1,9 +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>
@@ -26,34 +50,49 @@
  * string.
  */
 
-static char *template = "~/.pam_cr/auth";
+static const char *template = "~/.pam_cr/auth";
 
-void authfile_template(char *str)
+void authfile_template(const char *str)
 {
 	template = str;
 }
 
-static char *make_path(const char *tokenid, const char *userid)
+static int path_size(const char *tokenid, const char *userid)
 {
 	const char *usub;
-	char *path;
-	char *p, *q;
+	const 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 = 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 NULL;
+		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;
 	}
-	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 '~':
@@ -69,7 +108,19 @@ static char *make_path(const char *tokenid, const char *userid)
 		break;
 	}
 	*q = '\0';
-	return path;
+}
+
+int parse(char * const buf, const int argc, const char *argv[const])
+{
+	char *p, *q;
+	int i;
+
+	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,
@@ -81,52 +132,53 @@ struct _auth_obj authfile(const char *tokenid,
 						const int csize))
 {
 	struct _auth_obj ret = {0};
+	mode_t oldmask;
 	FILE *fp = NULL;
-	char *fn;
+	char *fn, *nfn;
+	int fnl;
+	struct stat st = {0};
 	char *buf = NULL;
-	const char *wtokenid = NULL, *wuserid = NULL, *wnonce = NULL;
-	const char *hablob = 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 ((fn = make_path(tokenid, userid)) == NULL) {
+	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");
-	free(fn);
 	if (fp) {
-		struct stat st;
-		int fd = fileno(fp);
-
-		if (fstat(fd, &st)) st.st_size = 2047;
+		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)) {
-			char *p;
-
-			p = &buf[strlen(buf) - 1];
-			while (*p == '\n' || *p == '\r') *p-- = '\0';
-			wtokenid = strtok(buf, ":");
-			wuserid = strtok(NULL, ":");
-			wnonce = strtok(NULL, ":");
-			hablob = strtok(NULL, ":");
-		} else {
+		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 (ret.err) return ret;
 
-	if (hablob) {
-		int hlen = strlen(hablob);
+	if (w.hablob) {
+		int hlen = strlen(w.hablob);
 		if (hlen % 32 != 0) {
 			ret.err = "error: auth string has wrong length";
 		} else if (hlen !=
-				strspn(hablob, "0123456789abcdefABCDEF")) {
+				strspn(w.hablob, "0123456789abcdefABCDEF")) {
 			ret.err = "error: auth string not hexadecimal";
 		} else {
 			int i;
@@ -134,20 +186,20 @@ struct _auth_obj authfile(const char *tokenid,
 			blobsize = hlen/2;
 			ablob = alloca(blobsize);
 			for (i = 0; i < blobsize; i++)
-				sscanf(&hablob[i*2], "%2hhx", &ablob[i]);
+				sscanf(&w.hablob[i*2], "%2hhx", &ablob[i]);
 		}
 	}
 	if (ret.err) return ret;
 
-	nonsize = wnonce ? strlen(wnonce)*2 : 32;
+	nonsize = w.nonce ? strlen(w.nonce)*2 : 32;
 	if (nonsize < 32) nonsize = 32;
 	newnonce = alloca(nonsize);
-	if (wnonce) strcpy(newnonce, wnonce);
+	if (w.nonce) strcpy(newnonce, w.nonce);
 	else memset(newnonce, 0, nonsize);
 	update_nonce(newnonce, nonsize);
 
-	ao = authobj(userid?userid:wuserid, password,
-			wnonce, newnonce, secret, secsize,
+	ao = authobj(userid?userid:w.userid, password,
+			w.nonce, newnonce, secret, secsize,
 			payload, paylsize, ablob, blobsize,
 			fetch_key);
 
@@ -159,41 +211,52 @@ struct _auth_obj authfile(const char *tokenid,
 		return ret;
 	}
 
-	if ((fp = fopen(fn, "w"))) {
+	oldmask = umask(077);
+	if ((fp = fopen(nfn, "w"))) {
 		int i;
 
-		if (fprintf(fp, "%s:%s:%s:", tokenid?tokenid:wtokenid,
-				userid?userid:wuserid, newnonce) < 0) {
+		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);
 		}
 		fprintf(fp, "\n");
+		if (st.st_uid || st.st_gid) {
+			if (fchown(fileno(fp), st.st_uid, st.st_gid)) /*ign*/;
+		}
 		if (fclose(fp) < 0) {
 			ret.err = strerror(errno);
 		}
 	} else {
 		ret.err = strerror(errno);
 	}
+	(void)umask(oldmask);
+	if (ret.err) {
+		unlink(nfn); /* may not exist but no matter */
+	} else if (rename(nfn, fn)) {
+		ret.err = strerror(errno);
+	}
 
 	if (!ret.err) {
-		int bufsize = (wuserid?strlen(wuserid)+1:0) + ao.paylsize;
+		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 (wuserid) {
-					strcpy((char*)p, wuserid);
+				if (w.userid) {
+					strcpy((char*)p, w.userid);
 					ret.data = p;
-					ret.datasize = strlen(wuserid)+1;
-					p += strlen(wuserid)+1;
+					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;
+					ret.paylsize = ao.paylsize+1;
 				}
 			}
 		}