Re: [PATCH] apparmor: fix SECURITY_APPARMOR_HASH_DEFAULT parameter handling

[Nathan Chancellor <natechancellor@gmail.com>]

On Mon, Sep 17, 2018 at 11:37:54PM +0200, Greg KH wrote:
> On Mon, Sep 17, 2018 at 11:15:42PM +0200, Greg KH wrote:
> > On Mon, Sep 17, 2018 at 09:45:47PM +0200, Loic wrote:
> > > On Mon, 17 Sep 2018 15:58:56 +0200
> > > Greg KH <gregkh@linuxfoundation.org> wrote:
> > > 
> > > > On Sun, Sep 09, 2018 at 04:04:18PM +0200, Loic wrote:
> > > > > Hello,
> > > > > 
> > > > > Tested without any problem so please picked up this for 4.4 to fix the
> > > > > problem.
> > > > > The patch below is slightly modified to adapt to this version.
> > > > > 
> > > > > [ Upstream commit 7616ac70d1bb4f2e9d25c1a82d283f3368a7b632 ]
> > > > > 
> > > > > The newly added Kconfig option could never work and just causes a build
> > > > > error
> > > > > when disabled:
> > > > > 
> > > > > security/apparmor/lsm.c:675:25: error:
> > > > > 'CONFIG_SECURITY_APPARMOR_HASH_DEFAULT' undeclared here (not in a function)
> > > > >  bool aa_g_hash_policy = CONFIG_SECURITY_APPARMOR_HASH_DEFAULT;
> > > > > 
> > > > > The problem is that the macro undefined in this case, and we need to use the
> > > > > IS_ENABLED()
> > > > > helper to turn it into a boolean constant.
> > > > > 
> > > > > Another minor problem with the original patch is that the option is even
> > > > > offered
> > > > > in sysfs when SECURITY_APPARMOR_HASH is not enabled, so this also hides the
> > > > > option
> > > > > in that case.
> > > > > 
> > > > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > > > > Fixes: 6059f71f1e94 ("apparmor: add parameter to control whether policy
> > > > > hashing is used")
> > > > > Signed-off-by: John Johansen <john.johansen@canonical.com>
> > > > > Signed-off-by: James Morris <james.l.morris@oracle.com>
> > > > > ---
> > > > > diff -Nurp a/security/apparmor/crypto.c b/security/apparmor/crypto.c
> > > > > --- a/security/apparmor/crypto.c
> > > > > +++ b/security/apparmor/crypto.c
> > > > > @@ -39,6 +39,9 @@ int aa_calc_profile_hash(struct aa_profi
> > > > >  	int error = -ENOMEM;
> > > > >  	u32 le32_version = cpu_to_le32(version);
> > > > > 
> > > > > +	if (!aa_g_hash_policy)
> > > > > +		return 0;
> > > > > +
> > > > >  	if (!apparmor_tfm)
> > > > >  		return 0;
> > > > > 
> > > > > diff -Nurp a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> > > > > --- a/security/apparmor/lsm.c
> > > > > +++ b/security/apparmor/lsm.c
> > > > > @@ -692,6 +692,12 @@ enum profile_mode aa_g_profile_mode = AP
> > > > >  module_param_call(mode, param_set_mode, param_get_mode,
> > > > >  		  &aa_g_profile_mode, S_IRUSR | S_IWUSR);
> > > > > 
> > > > > +#ifdef CONFIG_SECURITY_APPARMOR_HASH
> > > > > +/* whether policy verification hashing is enabled */
> > > > > +bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
> > > > > +module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR |
> > > > > S_IWUSR);
> > > > > +#endif
> > > > > +
> > > > >  /* Debug mode */
> > > > >  bool aa_g_debug;
> > > > >  module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
> > > > > ---
> > > > 
> > > > The patch is whitespace corrupted and can not be applied :(
> > > 
> > > Sorry, I noticed the problem afterwards. I opened a bug report to try to fix my mail client:
> > > https://github.com/roundcube/roundcubemail/issues/6438
> > > 
> > > > 
> > > > Can you fix that up and resend it so that I can apply it?
> > > 
> > > No problem. Thanks for all.
> > > 
> > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > > Fixes: 6059f71f1e94 ("apparmor: add parameter to control whether policy hashing is used")
> > > Signed-off-by: John Johansen <john.johansen@canonical.com>
> > > Signed-off-by: James Morris <james.l.morris@oracle.com>
> > > ---
> > > diff -Nurp a/security/apparmor/crypto.c b/security/apparmor/crypto.c
> > > --- a/security/apparmor/crypto.c
> > > +++ b/security/apparmor/crypto.c
> > > @@ -39,6 +39,9 @@ int aa_calc_profile_hash(struct aa_profi
> > >  	int error = -ENOMEM;
> > >  	u32 le32_version = cpu_to_le32(version);
> > >  
> > > +	if (!aa_g_hash_policy)
> > > +		return 0;
> > > +
> > >  	if (!apparmor_tfm)
> > >  		return 0;
> > >  
> > > diff -Nurp a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> > > --- a/security/apparmor/lsm.c
> > > +++ b/security/apparmor/lsm.c
> > > @@ -692,6 +694,12 @@ enum profile_mode aa_g_profile_mode = AP
> > >  module_param_call(mode, param_set_mode, param_get_mode,
> > >  		  &aa_g_profile_mode, S_IRUSR | S_IWUSR);
> > >  
> > > +#ifdef CONFIG_SECURITY_APPARMOR_HASH
> > > +/* whether policy verification hashing is enabled */
> > > +bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
> > > +module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | S_IWUSR);
> > > +#endif
> > > +
> > >  /* Debug mode */
> > >  bool aa_g_debug;
> > >  module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);
> > 
> > THanks, that worked, now queued up.
> 
> And dropped as this patch broke the build.  I'm guessing this really
> isn't needed if you didn't even test it worked :(
> 
> Please fix all of this up, test it properly, and then send it as a
> "clean" patch that I can apply easily.
> 
> thanks,
> 
> greg k-h

Commit 6059f71f1e94 ("apparmor: add parameter to control whether policy 
hashing is used") didn't even come in until 4.8 and SECURITY_APPARMOR_HASH_DEFAULT
isn't defined anywhere in 4.4. Fairly certain this isn't needed at all.

Cheers,
Nathan