Re: [PATCH] net: Initialize ctx to avoid memory allocation error
From: Casey Schaufler
Date: Fri Mar 14 2025 - 13:26:51 EST
On 3/14/2025 9:47 AM, Florian Westphal wrote:
> Casey Schaufler <casey@xxxxxxxxxxxxxxxx> wrote:
>> If seclen is 0 it implies that there is no security context and that
>> the secctx is NULL. How that is handled in the release function is up
>> to the LSM. SELinux allocates secctx data, while Smack points to an
>> entry in a persistent table.
>>
>>> seclen needs to be > 0 or no secinfo is passed to userland,
>>> yet the secctx release function is called anyway.
>> That is correct. The security module is responsible for handling
>> the release of secctx correctly.
>>
>>> Should seclen be initialised to -1? Or we need the change below too?
>> No. The security modules handle secctx their own way.
> Well, as-is security_release_secctx() can be called with garbage ctx;
> seclen is inited to 0, but ctx is not initialized unconditionally.
Which isn't an issue for any existing security module.