2021-12-02 03:12:34

by 赵军奎

Subject: [PATCH] security/selinux: fix potential memleak in error branch

This patch try to fix potential memleak in error branch.

Signed-off-by: Bernard Zhao <[email protected]>
---
security/selinux/hooks.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 62d30c0a30c2..10700720bb74 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -983,6 +983,7 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
static int selinux_add_opt(int token, const char *s, void **mnt_opts)
{
struct selinux_mnt_opts *opts = *mnt_opts;
+ bool is_alloc_opts = false;

if (token == Opt_seclabel) /* eaten and completely ignored */
return 0;
@@ -992,9 +993,13 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
if (!opts)
return -ENOMEM;
*mnt_opts = opts;
+ is_alloc_opts = true;
}
- if (!s)
+ if (!s) {
+ if (is_alloc_opts)
+ kfree(opts);
return -ENOMEM;
+ }
switch (token) {
case Opt_context:
if (opts->context || opts->defcontext)
@@ -1020,6 +1025,8 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
return 0;
Einval:
pr_warn(SEL_MOUNT_FAIL_MSG);
+ if (is_alloc_opts)
+ kfree(opts);
return -EINVAL;
}

--
2.33.1

2021-12-06 03:23:10

by Paul Moore

Subject: Re: [PATCH] security/selinux: fix potential memleak in error branch

On Wed, Dec 1, 2021 at 10:12 PM Bernard Zhao <[email protected]> wrote:
>
> This patch try to fix potential memleak in error branch.
>
> Signed-off-by: Bernard Zhao <[email protected]>
> ---
> security/selinux/hooks.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 62d30c0a30c2..10700720bb74 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -983,6 +983,7 @@ static int selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
> static int selinux_add_opt(int token, const char *s, void **mnt_opts)
> {
> struct selinux_mnt_opts *opts = *mnt_opts;
> + bool is_alloc_opts = false;
>
> if (token == Opt_seclabel) /* eaten and completely ignored */
> return 0;
> @@ -992,9 +993,13 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
> if (!opts)
> return -ENOMEM;
> *mnt_opts = opts;
> + is_alloc_opts = true;
> }
> - if (!s)
> + if (!s) {
> + if (is_alloc_opts)
> + kfree(opts);
> return -ENOMEM;
> + }

Thanks for catching this and submitting a patch, but would it be
simpler to do the "(!s)" check before the "(!opts)" check?

> switch (token) {
> case Opt_context:
> if (opts->context || opts->defcontext)
> @@ -1020,6 +1025,8 @@ static int selinux_add_opt(int token, const char *s, void **mnt_opts)
> return 0;
> Einval:
> pr_warn(SEL_MOUNT_FAIL_MSG);
> + if (is_alloc_opts)
> + kfree(opts);
> return -EINVAL;
> }
>
> --
> 2.33.1

--
paul moore
http://www.paul-moore.com