[20/25] libselinux: matchpathcon: free memory on realloc failure

Commit Message

Christian Göttsche May 3, 2021, 5:53 p.m. UTC

In case `realloc()` fails and returns NULL, free the passed array,
instead of just setting the size helper variables to 0.

Also free the string contents in `free_array_elts()` of the array
`con_array`, instead of just the array of pointers.

Found by cppcheck.

src/matchpathcon.c:86:4: error: Common realloc mistake: 'con_array' nulled but not freed upon failure [memleakOnRealloc]
   con_array = (char **)realloc(con_array, sizeof(char*) *
   ^

Signed-off-by: Christian Göttsche <[e-mail]>
---
 libselinux/src/matchpathcon.c | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

Patch

diff --git a/libselinux/src/matchpathcon.c b/libselinux/src/matchpathcon.c
index 9e1fab59..075a3fb3 100644
--- a/libselinux/src/matchpathcon.c
+++ b/libselinux/src/matchpathcon.c
@@ -78,17 +78,30 @@  static pthread_once_t once = PTHREAD_ONCE_INIT;
 static pthread_key_t destructor_key;
 static int destructor_key_initialized = 0;
 
+static void free_array_elts(void)
+{
+	int i;
+	for (i = 0; i < con_array_used; i++)
+		free(con_array[i]);
+	free(con_array);
+
+	con_array_size = con_array_used = 0;
+	con_array = NULL;
+}
+
 static int add_array_elt(char *con)
 {
+	char **tmp;
 	if (con_array_size) {
 		while (con_array_used >= con_array_size) {
 			con_array_size *= 2;
-			con_array = (char **)realloc(con_array, sizeof(char*) *
+			tmp = (char **)realloc(con_array, sizeof(char*) *
 						     con_array_size);
-			if (!con_array) {
-				con_array_size = con_array_used = 0;
+			if (!tmp) {
+				free_array_elts();
 				return -1;
 			}
+			con_array = tmp;
 		}
 	} else {
 		con_array_size = 1000;
@@ -105,13 +118,6 @@  static int add_array_elt(char *con)
 	return con_array_used++;
 }
 
-static void free_array_elts(void)
-{
-	con_array_size = con_array_used = 0;
-	free(con_array);
-	con_array = NULL;
-}
-
 void set_matchpathcon_invalidcon(int (*f) (const char *p, unsigned l, char *c))
 {
 	myinvalidcon = f;