[BlueZ,v1,4/4] settings: limit the number of chars to be read in gatt_db_load()

Commit Message

Roman Smirnov July 9, 2024, noon UTC

It is necessary to limit the string length to prevent buffer overflow.
Find the string length, write it to the pattern and use it for
limiting.

Found with the SVACE static analysis tool.
---
 src/settings.c | 39 +++++++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

Patch

diff --git a/src/settings.c b/src/settings.c
index 4eccf0b4e..dcfbc5601 100644
--- a/src/settings.c
+++ b/src/settings.c
@@ -243,13 +243,32 @@  static int gatt_db_load(struct gatt_db *db, GKeyFile *key_file, char **keys)
 	struct gatt_db_attribute *current_service;
 	char **handle, *value, type[MAX_LEN_UUID_STR];
 	int ret;
+	char pattern[6];
+	char *colon_pos;
+	size_t len;
 
 	/* first load service definitions */
 	for (handle = keys; *handle; handle++) {
 		value = g_key_file_get_string(key_file, "Attributes", *handle,
 									NULL);
+		if (!value)
+			return -EIO;
+
+		colon_pos = memchr(value, ':', MAX_LEN_UUID_STR);
+		if (!colon_pos) {
+			g_free(value);
+			return -EIO;
+		}
+
+		len = colon_pos - value;
+		if (!len) {
+			g_free(value);
+			return -EIO;
+		}
 
-		if (!value || sscanf(value, "%[^:]:", type) != 1) {
+		snprintf(pattern, sizeof(pattern), "%%%lds:", len);
+
+		if (sscanf(value, pattern, type) != 1) {
 			g_free(value);
 			return -EIO;
 		}
@@ -271,8 +290,24 @@  static int gatt_db_load(struct gatt_db *db, GKeyFile *key_file, char **keys)
 	for (handle = keys; *handle; handle++) {
 		value = g_key_file_get_string(key_file, "Attributes", *handle,
 									NULL);
+		if (!value)
+			return -EIO;
+
+		colon_pos = memchr(value, ':', MAX_LEN_UUID_STR);
+		if (!colon_pos) {
+			g_free(value);
+			return -EIO;
+		}
+
+		len = colon_pos - value;
+		if (!len) {
+			g_free(value);
+			return -EIO;
+		}
+
+		snprintf(pattern, sizeof(pattern), "%%%lds:", len);
 
-		if (!value || sscanf(value, "%[^:]:", type) != 1) {
+		if (sscanf(value, pattern, type) != 1) {
 			g_free(value);
 			return -EIO;
 		}