/pidgin/main: 9a2250c4e9d1: Fix Coverity TOCTOU warnings

Changeset: 9a2250c4e9d17b409133dda9a6074914094dcade
Author:	 Tomasz Wasilczyk <[email protected]>
Date:	 2014-05-12 23:55 +0200
Branch:	 release-2.x.y
URL: https://hg.pidgin.im/pidgin/main/rev/9a2250c4e9d1

Description:

Fix Coverity TOCTOU warnings

diffstat:

 libpurple/log.c                 |  25 +++++-----
 libpurple/protocols/silc/util.c |  95 +++++++++-------------------------------
 libpurple/util.c                |   7 ++-
 3 files changed, 42 insertions(+), 85 deletions(-)

diffs (213 lines):

diff --git a/libpurple/log.c b/libpurple/log.c
--- a/libpurple/log.c
+++ b/libpurple/log.c
@@ -1676,7 +1676,7 @@ static GList *old_logger_list(PurpleLogT
 	time_t log_last_modified;
 	FILE *index;
 	FILE *file;
-	int index_fd;
+	int file_fd, index_fd;
 	char *index_tmp;
 	char buf[BUF_LONG];
 	struct tm tm;
@@ -1692,13 +1692,21 @@ static GList *old_logger_list(PurpleLogT
 
 	g_free(logfile);
 
-	if (g_stat(purple_stringref_value(pathref), &st))
-	{
+	file_fd = g_open(purple_stringref_value(pathref), 0, O_RDONLY);
+	if (file_fd == -1 || (file = fdopen(file_fd, "rb")) == NULL) {
+		purple_debug_error("log",
+			"Failed to open log file \"%s\" for reading: %s\n",
+			purple_stringref_value(pathref), g_strerror(errno));
 		purple_stringref_unref(pathref);
 		g_free(pathstr);
 		return NULL;
 	}
-	else
+	if (fstat(file_fd, &st) == -1) {
+		purple_stringref_unref(pathref);
+		g_free(pathstr);
+		fclose(file);
+		return NULL;
+	} else
 		log_last_modified = st.st_mtime;
 
 	/* Change the .log extension to .idx */
@@ -1752,19 +1760,12 @@ static GList *old_logger_list(PurpleLogT
 				fclose(index);
 				purple_stringref_unref(pathref);
 
+				fclose(file);
 				return list;
 			}
 		}
 	}
 
-	if (!(file = g_fopen(purple_stringref_value(pathref), "rb"))) {
-		purple_debug_error("log", "Failed to open log file \"%s\" for reading: %s\n",
-		                   purple_stringref_value(pathref), g_strerror(errno));
-		purple_stringref_unref(pathref);
-		g_free(pathstr);
-		return NULL;
-	}
-
 	index_tmp = g_strdup_printf("%s.XXXXXX", pathstr);
 	if ((index_fd = g_mkstemp(index_tmp)) == -1) {
 		purple_debug_error("log", "Failed to open index temp file: %s\n",
diff --git a/libpurple/protocols/silc/util.c b/libpurple/protocols/silc/util.c
--- a/libpurple/protocols/silc/util.c
+++ b/libpurple/protocols/silc/util.c
@@ -92,104 +92,55 @@ gboolean silcpurple_check_silc_dir(Purpl
 	g_snprintf(friendsfilename, sizeof(friendsfilename) - 1, "%s" G_DIR_SEPARATOR_S "friends",
 		   silcpurple_silcdir());
 
+	if (pw->pw_uid != geteuid()) {
+		purple_debug_error("silc", "Couldn't create directories due to wrong uid!\n");
+		return FALSE;
+	}
+
 	/*
 	 * Check ~/.silc directory
 	 */
+	if (g_mkdir(filename, 0755) != 0 && errno != EEXIST) {
+		purple_debug_error("silc", "Couldn't create '%s' directory\n", filename);
+		return FALSE;
+	}
+
+#ifndef _WIN32
 	if ((g_stat(filename, &st)) == -1) {
-		/* If dir doesn't exist */
-		if (errno == ENOENT) {
-			if (pw->pw_uid == geteuid()) {
-				if ((g_mkdir(filename, 0755)) == -1) {
-					purple_debug_error("silc", "Couldn't create '%s' directory\n", filename);
-					return FALSE;
-				}
-			} else {
-				purple_debug_error("silc", "Couldn't create '%s' directory due to a wrong uid!\n",
-					filename);
-				return FALSE;
-			}
-		} else {
-			purple_debug_error("silc", "Couldn't stat '%s' directory, error: %s\n", filename, g_strerror(errno));
-			return FALSE;
-		}
+		purple_debug_error("silc", "Couldn't stat '%s' directory, error: %s\n", filename, g_strerror(errno));
+		return FALSE;
 	} else {
-#ifndef _WIN32
 		/* Check the owner of the dir */
 		if (st.st_uid != 0 && st.st_uid != pw->pw_uid) {
 			purple_debug_error("silc", "You don't seem to own '%s' directory\n",
 				filename);
 			return FALSE;
 		}
+	}
 #endif
-	}
 
 	/*
 	 * Check ~./silc/serverkeys directory
 	 */
-	if ((g_stat(servfilename, &st)) == -1) {
-		/* If dir doesn't exist */
-		if (errno == ENOENT) {
-			if (pw->pw_uid == geteuid()) {
-				if ((g_mkdir(servfilename, 0755)) == -1) {
-					purple_debug_error("silc", "Couldn't create '%s' directory\n", servfilename);
-					return FALSE;
-				}
-			} else {
-				purple_debug_error("silc", "Couldn't create '%s' directory due to a wrong uid!\n",
-					servfilename);
-				return FALSE;
-			}
-		} else {
-			purple_debug_error("silc", "Couldn't stat '%s' directory, error: %s\n",
-							 servfilename, g_strerror(errno));
-			return FALSE;
-		}
+	if (g_mkdir(servfilename, 0755) != 0 && errno != EEXIST) {
+		purple_debug_error("silc", "Couldn't create '%s' directory\n", servfilename);
+		return FALSE;
 	}
 
 	/*
 	 * Check ~./silc/clientkeys directory
 	 */
-	if ((g_stat(clientfilename, &st)) == -1) {
-		/* If dir doesn't exist */
-		if (errno == ENOENT) {
-			if (pw->pw_uid == geteuid()) {
-				if ((g_mkdir(clientfilename, 0755)) == -1) {
-					purple_debug_error("silc", "Couldn't create '%s' directory\n", clientfilename);
-					return FALSE;
-				}
-			} else {
-				purple_debug_error("silc", "Couldn't create '%s' directory due to a wrong uid!\n",
-					clientfilename);
-				return FALSE;
-			}
-		} else {
-			purple_debug_error("silc", "Couldn't stat '%s' directory, error: %s\n",
-							 clientfilename, g_strerror(errno));
-			return FALSE;
-		}
+	if (g_mkdir(clientfilename, 0755) != 0 && errno != EEXIST) {
+		purple_debug_error("silc", "Couldn't create '%s' directory\n", clientfilename);
+		return FALSE;
 	}
 
 	/*
 	 * Check ~./silc/friends directory
 	 */
-	if ((g_stat(friendsfilename, &st)) == -1) {
-		/* If dir doesn't exist */
-		if (errno == ENOENT) {
-			if (pw->pw_uid == geteuid()) {
-				if ((g_mkdir(friendsfilename, 0755)) == -1) {
-					purple_debug_error("silc", "Couldn't create '%s' directory\n", friendsfilename);
-					return FALSE;
-				}
-			} else {
-				purple_debug_error("silc", "Couldn't create '%s' directory due to a wrong uid!\n",
-					friendsfilename);
-				return FALSE;
-			}
-		} else {
-			purple_debug_error("silc", "Couldn't stat '%s' directory, error: %s\n",
-							 friendsfilename, g_strerror(errno));
-			return FALSE;
-		}
+	if (g_mkdir(friendsfilename, 0755) != 0 && errno != EEXIST) {
+		purple_debug_error("silc", "Couldn't create '%s' directory\n", friendsfilename);
+		return FALSE;
 	}
 
 	/*
diff --git a/libpurple/util.c b/libpurple/util.c
--- a/libpurple/util.c
+++ b/libpurple/util.c
@@ -2696,7 +2696,11 @@ purple_util_write_data_to_file_absolute(
 		g_free(filename_temp);
 		return FALSE;
 	}
-	/* Use stat to be absolutely sure. */
+#ifndef __COVERITY__
+	/* Use stat to be absolutely sure.
+	 * It causes TOCTOU coverity warning (against g_rename below),
+	 * but it's not a threat for us.
+	 */
 	if ((g_stat(filename_temp, &st) == -1) || (st.st_size != real_size))
 	{
 		purple_debug_error("util", "Error writing data to file %s: "
@@ -2706,6 +2710,7 @@ purple_util_write_data_to_file_absolute(
 		g_free(filename_temp);
 		return FALSE;
 	}
+#endif /* __COVERITY__ */
 
 	/* Rename to the REAL name */
 	if (g_rename(filename_temp, filename_full) == -1)