[3/3] selinux: Use an other error code for an input validation failure in sidtab_insert()

Commit Message

SF Markus Elfring April 4, 2017, 11:16 a.m. UTC

From: Markus Elfring <[e-mail]>
Date: Tue, 4 Apr 2017 12:23:41 +0200

The error code "-ENOMEM" was also returned so far when the parameter "s"
of this function contained a null pointer.
Now I find that the code "-EINVAL" is more appropriate in this case.

Signed-off-by: Markus Elfring <[e-mail]>
---
 security/selinux/ss/sidtab.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Paul Moore May 16, 2017, 6:41 p.m. UTC | #1

On Tue, Apr 4, 2017 at 7:16 AM, SF Markus Elfring
<[e-mail]> wrote:
> From: Markus Elfring <[e-mail]>
> Date: Tue, 4 Apr 2017 12:23:41 +0200
>
> The error code "-ENOMEM" was also returned so far when the parameter "s"
> of this function contained a null pointer.
> Now I find that the code "-EINVAL" is more appropriate in this case.
>
> Signed-off-by: Markus Elfring <[e-mail]>
> ---
>  security/selinux/ss/sidtab.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Have you tested this to determine any impact it may have on the
SELinux userspace?  I would agree that EINVAL is probably more
appropriate in this case, but changing this return code has very
little value and may disrupt userspace if it assumes EINVAL means
something else when the policy load fails.  Without a demonstration
that all the code paths have been tested I'm not inclined to merge
this patch.

> diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
> index c5f436b15d19..2eb2a54b88d2 100644
> --- a/security/selinux/ss/sidtab.c
> +++ b/security/selinux/ss/sidtab.c
> @@ -36,7 +36,7 @@ int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
>         struct sidtab_node *prev, *cur, *newnode;
>
>         if (!s)
> -               return -ENOMEM;
> +               return -EINVAL;
>
>         hvalue = SIDTAB_HASH(sid);
>         prev = NULL;
> --
> 2.12.2

SF Markus Elfring May 16, 2017, 7:57 p.m. UTC | #2

> Have you tested this to determine any impact it may have on the
> SELinux userspace?

Not yet.


> I would agree that EINVAL is probably more appropriate in this case,

Thanks that a part of your view seems to fit also to mine.


> but changing this return code has very little value

I would appreciate if this aspect can clarified a bit more.


> and may disrupt userspace if it assumes EINVAL means something else
> when the policy load fails.

Would you find an other error code better there?

Do you care to distinguish an input validation failure in a specific
function implementation from other error situations?

Regards,
Markus

Patch

diff --git a/security/selinux/ss/sidtab.c b/security/selinux/ss/sidtab.c
index c5f436b15d19..2eb2a54b88d2 100644
--- a/security/selinux/ss/sidtab.c
+++ b/security/selinux/ss/sidtab.c
@@ -36,7 +36,7 @@  int sidtab_insert(struct sidtab *s, u32 sid, struct context *context)
 	struct sidtab_node *prev, *cur, *newnode;
 
 	if (!s)
-		return -ENOMEM;
+		return -EINVAL;
 
 	hvalue = SIDTAB_HASH(sid);
 	prev = NULL;