[PATCH] mtd: phram: fix a double free issue in error path

From: Wen Yang
Date: Wed Mar 18 2020 - 11:28:37 EST


The variable 'name' is released multiple times in the error path,
which may cause double.
This problem is avoided by adding a goto label to release memory
uniformly. This change also makes the code a bit more cleaner.

Fixes: 4f678a58d335 ("mtd: fix memory leaks in phram_setup")
Signed-off-by: Wen Yang <wenyang@xxxxxxxxxxxxxxxxx>
Cc: Joern Engel <joern@xxxxxxxxxxxxxxx>
Cc: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: Vignesh Raghavendra <vigneshr@xxxxxx>
Cc: linux-mtd@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/mtd/devices/phram.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index 931e5c2481b5..b50ec7ecd10c 100644
--- a/drivers/mtd/devices/phram.c
+++ b/drivers/mtd/devices/phram.c
@@ -243,22 +243,25 @@ static int phram_setup(const char *val)

ret = parse_num64(&start, token[1]);
if (ret) {
- kfree(name);
parse_err("illegal start address\n");
+ goto error;
}

ret = parse_num64(&len, token[2]);
if (ret) {
- kfree(name);
parse_err("illegal device length\n");
+ goto error;
}

ret = register_device(name, start, len);
- if (!ret)
- pr_info("%s device: %#llx at %#llx\n", name, len, start);
- else
- kfree(name);
+ if (ret)
+ goto error;
+
+ pr_info("%s device: %#llx at %#llx\n", name, len, start);
+ return 0;

+error:
+ kfree(name);
return ret;
}

--
2.23.0