freshclam, libclamav: work around possible race condition during db updates (bb#1624)

ChangeLog

@@ -1,3 +1,8 @@
+Tue Aug  4 15:10:12 CEST 2009 (tk)
+----------------------------------
+ * freshclam, libclamav: work around possible race condition during
+			 db updates (bb#1624)
+
 Mon Aug  3 15:22:42 CEST 2009 (tk)
 ----------------------------------
  * freshclam/manager.c: fix confusing error message (bb#1648)

freshclam/manager.c

@@ -1683,18 +1683,12 @@ static int updatedb(const char *dbname, const char *hostname, char *ip, int *sig
 	return 55; /* FIXME */
     }
 
-    if(!nodb && !access(localname, R_OK) && unlink(localname)) {
-	logg("!Can't unlink %s. Please fix it and try again.\n", localname);
-	unlink(newfile);
-	free(newfile);
-	return 53;
-    }
-
 #ifdef C_WINDOWS
     if(!access(newdb, R_OK) && unlink(newdb)) {
 	logg("!Can't unlink %s. Please fix the problem manually and try again.\n", newdb);
 	unlink(newfile);
 	free(newfile);
+	cl_cvdfree(current);
 	return 53;
     }
 #endif
@@ -1703,10 +1697,15 @@ static int updatedb(const char *dbname, const char *hostname, char *ip, int *sig
 	logg("!Can't rename %s to %s: %s\n", newfile, newdb, strerror(errno));
 	unlink(newfile);
 	free(newfile);
+	cl_cvdfree(current);
 	return 57;
     }
     free(newfile);
 
+    if(!nodb && !access(localname, R_OK) && strcmp(newdb, localname))
+	if(unlink(localname))
+	    logg("^Can't unlink the old database file %s. Please remove it manually.\n", localname);
+
     logg("%s updated (version: %d, sigs: %d, f-level: %d, builder: %s)\n", newdb, current->version, current->sigs, current->fl, current->builder);
 
     if(flevel < current->fl) {

libclamav/clamav.h

@@ -79,6 +79,7 @@ typedef enum {
 #define CL_DB_PUA_INCLUDE   0x100
 #define CL_DB_PUA_EXCLUDE   0x200
 #define CL_DB_COMPILED	    0x400   /* internal */
+#define CL_DB_DIRECTORY	    0x800   /* internal */
 
 /* recommended db settings */
 #define CL_DB_STDOPT	    (CL_DB_PHISHING | CL_DB_PHISHING_URLS | CL_DB_CVDNOTMP)

libclamav/readdb.c

@@ -39,6 +39,7 @@
 #endif
 #include <fcntl.h>
 #include <zlib.h>
+#include <errno.h>
 
 #include "clamav.h"
 #include "cvd.h"
@@ -1525,6 +1526,14 @@ int cli_load(const char *filename, struct cl_engine *engine, unsigned int *signo
 
 
     if(!dbio && (fs = fopen(filename, "rb")) == NULL) {
+	if(options & CL_DB_DIRECTORY) { /* bb#1624 */
+	    if(access(filename, R_OK)) {
+		if(errno == ENOENT) {
+		    cli_dbgmsg("Detected race condition, ignoring old file %s\n", filename);
+		    return CL_SUCCESS;
+		}
+	    }
+	}
 	cli_errmsg("cli_load(): Can't open file %s\n", filename);
 	return CL_EOPEN;
     }
@@ -1769,7 +1778,7 @@ int cl_load(const char *path, struct cl_engine *engine, unsigned int *signo, uns
 	    break;
 
 	case S_IFDIR:
-	    ret = cli_loaddbdir(path, engine, signo, dboptions);
+	    ret = cli_loaddbdir(path, engine, signo, dboptions | CL_DB_DIRECTORY);
 	    break;
 
 	default: