Re: [PATCH v14 3/6] LSM: Explicit individual LSM associations

From: Casey Schaufler
Date: Mon Jul 29 2013 - 21:48:33 EST


On 7/29/2013 1:51 PM, Kees Cook wrote:
> On Thu, Jul 25, 2013 at 11:32 AM, Casey Schaufler
> <casey@xxxxxxxxxxxxxxxx> wrote:
>> Subject: [PATCH v14 3/6] LSM: Explicit individual LSM associations
>> [...]
>> Introduce feature specific security operation vectors
>> for NetLabel, XFRM, secmark and presentation in the
>> traditional /proc/.../attr interfaces. This allows
>> proper handling of secids.
>> [...]
>> --- a/include/linux/lsm.h
>> +++ b/include/linux/lsm.h
>> @@ -164,9 +164,18 @@ static inline void lsm_init_secid(struct secids *secid, u32 lsecid, int order)
>> {
>> memset(secid, 0, sizeof(*secid));
>>
>> - if (lsecid != 0)
>> + if (lsecid == 0)
>> + return;
>> + /*
>> + * An order of -1 means set it for all LSMs.
>> + */
>> + if (order < 0) {
>> + secid->si_lsm[0] = lsecid;
>> + secid->si_count++;
>> + } else {
>> + secid->si_lsm[order] = lsecid;
>> secid->si_count = 1;
>> - secid->si_lsm[order] = lsecid;
>> + }
>> }
>>
>> static inline int lsm_zero_secid(struct secids *secid)
>> @@ -178,39 +187,64 @@ static inline int lsm_zero_secid(struct secids *secid)
>>
>> #ifdef CONFIG_SECURITY
>>
>> +extern struct security_operations *present_ops;
>> static inline struct security_operations *lsm_present_ops(void)
>> {
>> - return security_ops;
>> + return present_ops;
>> }
>>
>> static inline int lsm_present_order(void)
>> {
>> - return 0;
>> + return present_ops->order;
>> }
>>
>> +#ifdef CONFIG_NETLABEL
>> +extern struct security_operations *netlbl_ops;
>> +
>> static inline struct security_operations *lsm_netlbl_ops(void)
>> {
>> - return security_ops;
>> + return netlbl_ops;
>> }
>>
>> static inline int lsm_netlbl_order(void)
>> {
>> - return 0;
>> + return netlbl_ops->order;
>> }
>> +#endif /* CONFIG_NETLABEL */
>> +
>> +#ifdef CONFIG_SECURITY_NETWORK_XFRM
>> +extern struct security_operations *xfrm_ops;
>>
>> static inline struct security_operations *lsm_xfrm_ops(void)
>> {
>> - return security_ops;
>> + return xfrm_ops;
>> }
>>
>> static inline int lsm_xfrm_order(void)
>> {
>> - return 0;
>> + return xfrm_ops->order;
>> }
>> +#endif /* CONFIG_SECURITY_NETWORK_XFRM */
>> +
>> +#ifdef CONFIG_NETWORK_SECMARK
>> +extern struct security_operations *secmark_ops;
>>
>> static inline struct security_operations *lsm_secmark_ops(void)
>> {
>> - return security_ops;
>> + return secmark_ops;
>> +}
>> +
>> +static inline int lsm_secmark_order(void)
>> +{
>> + return secmark_ops->order;
>> +}
>> +#endif /* CONFIG_NETWORK_SECMARK */
>> +
>> +#else /* CONFIG_SECURITY */
>> +
>> +static inline int lsm_xfrm_order(void)
>> +{
>> + return 0;
>> }
>>
>> static inline int lsm_secmark_order(void)
>> @@ -218,6 +252,11 @@ static inline int lsm_secmark_order(void)
>> return 0;
>> }
>>
>> +static inline struct security_operations *lsm_secmark_ops(void)
>> +{
>> + return NULL;
>> +}
>> +
>> #endif /* CONFIG_SECURITY */
>>
>> #endif /* ! _LINUX_LSM_H */
> Something went wrong here with the #ifdef/#else stuff here. I built
> without CONFIG_SECURITY_NETWORK_XFRM and it fails, missing
> lsm_xfrm_order().
>
> If I added an #else to the CONFIG_SECURITY_NETWORK_XFRM check and made
> lsm_xfrm_order() return 0 there too, it built fine.

Yup, I missed that configuration iteration at the end.
I've incorporated a fix.

>
> -Kees
>

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