2020-03-18 15:32:53

by Wen Yang

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

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

Fixes: 4f678a58d335 ("mtd: fix memory leaks in phram_setup")
Signed-off-by: Wen Yang <[email protected]>
Cc: Joern Engel <[email protected]>
Cc: Miquel Raynal <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Vignesh Raghavendra <[email protected]>
Cc: [email protected]
Cc: [email protected]
---
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

2020-03-24 22:07:15

by Miquel Raynal

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

On Wed, 2020-03-18 at 15:31:56 UTC, Wen Yang wrote:
> The variable 'name' is released multiple times in the error path,
> which may cause double free issues.
> This problem is avoided by adding a goto label to release the mem
> uniformly. And this change also makes the code a bit more cleaner.
>
> Fixes: 4f678a58d335 ("mtd: fix memory leaks in phram_setup")
> Signed-off-by: Wen Yang <[email protected]>
> Cc: Joern Engel <[email protected]>
> Cc: Miquel Raynal <[email protected]>
> Cc: Richard Weinberger <[email protected]>
> Cc: Vignesh Raghavendra <[email protected]>
> Cc: [email protected]
> Cc: [email protected]

Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git mtd/next, thanks.

Miquel