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From: Bastien Nocera <hadess@hadess.net>
To: linux-bluetooth@vger.kernel.org
Cc: Bastien Nocera <hadess@hadess.net>
Subject: [BlueZ] main: Simplify parse_config_string()
Date: Mon, 27 May 2024 10:26:51 +0200
Message-ID: <20240527082730.967400-1-hadess@hadess.net>
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The memory management done by parse_config_string() was quite
complicated, as it expected to be able to free the value in the return
variable if it was already allocated.

That particular behaviour was only used for a single variable which was
set to its default value during startup and might be overwritten after
this function call.

Use an intermediate variable to check whether we need to free
btd_opts.name and simplify parse_config_string().

Error: RESOURCE_LEAK (CWE-772): [#def39] [important]
bluez-5.75/src/main.c:425:2: alloc_fn: Storage is returned from allocation function "g_key_file_get_string".
bluez-5.75/src/main.c:425:2: var_assign: Assigning: "tmp" = storage returned from "g_key_file_get_string(config, group, key, &err)".
bluez-5.75/src/main.c:433:2: noescape: Assuming resource "tmp" is not freed or pointed-to as ellipsis argument to "btd_debug".
bluez-5.75/src/main.c:440:2: leaked_storage: Variable "tmp" going out of scope leaks the storage it points to.
438|	}
439|
440|->	return true;
441|   }
442|
---
Essentially a v3 of "main: Simplify variable assignment" with a better
commit message.

 src/main.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/main.c b/src/main.c
index ac840d684f6d..f6369a20d879 100644
--- a/src/main.c
+++ b/src/main.c
@@ -420,9 +420,10 @@ static bool parse_config_string(GKeyFile *config, const char *group,
 					const char *key, char **val)
 {
 	GError *err = NULL;
-	char *tmp;
 
-	tmp = g_key_file_get_string(config, group, key, &err);
+	g_return_val_if_fail(val, false);
+
+	*val = g_key_file_get_string(config, group, key, &err);
 	if (err) {
 		if (err->code != G_KEY_FILE_ERROR_KEY_NOT_FOUND)
 			DBG("%s", err->message);
@@ -430,12 +431,7 @@ static bool parse_config_string(GKeyFile *config, const char *group,
 		return false;
 	}
 
-	DBG("%s.%s = %s", group, key, tmp);
-
-	if (val) {
-		g_free(*val);
-		*val = tmp;
-	}
+	DBG("%s.%s = %s", group, key, *val);
 
 	return true;
 }
@@ -1005,7 +1001,12 @@ static void parse_secure_conns(GKeyFile *config)
 
 static void parse_general(GKeyFile *config)
 {
-	parse_config_string(config, "General", "Name", &btd_opts.name);
+	char *str = NULL;
+
+	if (parse_config_string(config, "General", "Name", &str)) {
+		g_free(btd_opts.name);
+		btd_opts.name = str;
+	}
 	parse_config_hex(config, "General", "Class", &btd_opts.class);
 	parse_config_u32(config, "General", "DiscoverableTimeout",
 						&btd_opts.discovto,
-- 
2.44.0