On 6/22/2020 5:32 PM, Tyler Hicks wrote:
> Ask the LSM to free its audit rule rather than directly calling kfree().
> Both AppArmor and SELinux do additional work in their audit_rule_free()
> hooks. Fix memory leaks by allowing the LSMs to perform necessary work.
>
> Fixes: b16942455193 ("ima: use the lsm policy update notifier")
> Signed-off-by: Tyler Hicks <[email protected]>
> Cc: Janne Karhunen <[email protected]>
> ---
> security/integrity/ima/ima.h | 6 ++++++
> security/integrity/ima/ima_policy.c | 2 +-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index df93ac258e01..de05d7f1d3ec 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -404,6 +404,7 @@ static inline void ima_free_modsig(struct modsig *modsig)
> #ifdef CONFIG_IMA_LSM_RULES
>
> #define security_filter_rule_init security_audit_rule_init
> +#define security_filter_rule_free security_audit_rule_free
> #define security_filter_rule_match security_audit_rule_match
In context this seems perfectly reasonable. If, however, you're
working with the LSM infrastructure this set of #defines is maddening.
The existing ones have been driving my nuts for the past few years,
so I'd like to discourage adding another. Since the security_filter_rule
functions are IMA specific they shouldn't be prefixed security_. I know
that it seems to be code churn/bikesheading, but we please change these:
static inline int ima_filter_rule_init(.....)
{
return security_audit_rule_init(.....);
}
and so forth. I understand if you don't want to make the change.
I have plenty of other things driving me crazy just now, so this
doesn't seem likely to push me over the edge.
>
> #else
> @@ -414,6 +415,11 @@ static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
> return -EINVAL;
> }
>
> +static inline void security_filter_rule_free(void *lsmrule)
> +{
> + return -EINVAL;
> +}
> +
> static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
> void *lsmrule)
> {
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index e493063a3c34..236a731492d1 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -258,7 +258,7 @@ static void ima_lsm_free_rule(struct ima_rule_entry *entry)
> int i;
>
> for (i = 0; i < MAX_LSM_RULES; i++) {
> - kfree(entry->lsm[i].rule);
> + security_filter_rule_free(entry->lsm[i].rule);
> kfree(entry->lsm[i].args_p);
> }
> kfree(entry);
On 2020-06-22 17:55:59, Casey Schaufler wrote:
> On 6/22/2020 5:32 PM, Tyler Hicks wrote:
> > Ask the LSM to free its audit rule rather than directly calling kfree().
> > Both AppArmor and SELinux do additional work in their audit_rule_free()
> > hooks. Fix memory leaks by allowing the LSMs to perform necessary work.
> >
> > Fixes: b16942455193 ("ima: use the lsm policy update notifier")
> > Signed-off-by: Tyler Hicks <[email protected]>
> > Cc: Janne Karhunen <[email protected]>
> > ---
> > security/integrity/ima/ima.h | 6 ++++++
> > security/integrity/ima/ima_policy.c | 2 +-
> > 2 files changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index df93ac258e01..de05d7f1d3ec 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -404,6 +404,7 @@ static inline void ima_free_modsig(struct modsig *modsig)
> > #ifdef CONFIG_IMA_LSM_RULES
> >
> > #define security_filter_rule_init security_audit_rule_init
> > +#define security_filter_rule_free security_audit_rule_free
> > #define security_filter_rule_match security_audit_rule_match
>
> In context this seems perfectly reasonable. If, however, you're
> working with the LSM infrastructure this set of #defines is maddening.
> The existing ones have been driving my nuts for the past few years,
> so I'd like to discourage adding another. Since the security_filter_rule
> functions are IMA specific they shouldn't be prefixed security_. I know
> that it seems to be code churn/bikesheading, but we please change these:
>
> static inline int ima_filter_rule_init(.....)
> {
> return security_audit_rule_init(.....);
> }
>
> and so forth. I understand if you don't want to make the change.
> I have plenty of other things driving me crazy just now, so this
> doesn't seem likely to push me over the edge.
I'd be happy to take a stab at that as a follow-up or a 13/12 patch. I'd
like to leave this one as-is for stable kernel reasons since it is
straightforward and simple.
Tyler
>
> >
> > #else
> > @@ -414,6 +415,11 @@ static inline int security_filter_rule_init(u32 field, u32 op, char *rulestr,
> > return -EINVAL;
> > }
> >
> > +static inline void security_filter_rule_free(void *lsmrule)
> > +{
> > + return -EINVAL;
> > +}
> > +
> > static inline int security_filter_rule_match(u32 secid, u32 field, u32 op,
> > void *lsmrule)
> > {
> > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> > index e493063a3c34..236a731492d1 100644
> > --- a/security/integrity/ima/ima_policy.c
> > +++ b/security/integrity/ima/ima_policy.c
> > @@ -258,7 +258,7 @@ static void ima_lsm_free_rule(struct ima_rule_entry *entry)
> > int i;
> >
> > for (i = 0; i < MAX_LSM_RULES; i++) {
> > - kfree(entry->lsm[i].rule);
> > + security_filter_rule_free(entry->lsm[i].rule);
> > kfree(entry->lsm[i].args_p);
> > }
> > kfree(entry);