bcache-tools: fix potential memoryleak problem in, may_add_item()

In may_add_item(), it will directly return 1 without freeing
variable tmp and closing fd, when the return value of detail_base()
is not equal to 0. In addition, we do not check whether
allocating memory for tmp is successful.

Here, we will check whether malloc() returns NULL, and
will free tmp and close fd when detail_base() fails.

Signed-off-by: Zhiqiang Liu <lzhq28@mail.ustc.edu.cn>
Signed-off-by: Coly Li <colyli@suse.de>

1 files changed, 17 insertions, 11 deletions

diff --git a/lib.c b/lib.c
index 05ce9b98..adad823d 100644
--- a/lib.c
+++ b/lib.c
@@ -378,7 +378,7 @@ int may_add_item(char *devname, struct list_head *head)
 	struct cache_sb sb;
 	char dev[512];
 	struct dev *tmp;
-	int ret;
+	int ret = 0;
 
 	if (strcmp(devname, ".") == 0 || strcmp(devname, "..") == 0)
 		return 0;
@@ -388,27 +388,33 @@ int may_add_item(char *devname, struct list_head *head)
 	if (fd == -1)
 		return 0;
 
-	if (pread(fd, &sb_disk, sizeof(sb_disk), SB_START) != sizeof(sb_disk)) {
-		close(fd);
-		return 0;
-	}
+	if (pread(fd, &sb_disk, sizeof(sb_disk), SB_START) != sizeof(sb_disk))
+		goto out;
 
-	if (memcmp(sb_disk.magic, bcache_magic, 16)) {
-		close(fd);
-		return 0;
-	}
+	if (memcmp(sb_disk.magic, bcache_magic, 16))
+		goto out;
 
 	to_cache_sb(&sb, &sb_disk);
 
 	tmp = (struct dev *) malloc(DEVLEN);
+	if (tmp == NULL) {
+		fprintf(stderr, "Error: fail to allocate memory buffer\n");
+		ret = 1;
+		goto out;
+	}
+
 	tmp->csum = le64_to_cpu(sb_disk.csum);
 	ret = detail_base(dev, sb, tmp);
 	if (ret != 0) {
 		fprintf(stderr, "Failed to get information for %s\n", dev);
-		return 1;
+		free(tmp);
+		goto out;
 	}
 	list_add_tail(&tmp->dev_list, head);
-	return 0;
+
+out:
+	close(fd);
+	return ret;
 }
 
 int list_bdevs(struct list_head *head)