On Thu, 2010-01-07 at 15:55 -0500, Stephen Smalley wrote: > Per https://bugzilla.redhat.com/show_bug.cgi?id=548145 > there are sufficient range transition rules in modern (Fedora) policy to > make mls_compute_sid a significant factor on the shmem file setup path > due to the length of the range_tr list. Replace the simple range_tr > list with a hashtab inside the security server to help mitigate this > problem. > > Signed-off-by: Stephen D. Smalley <sds@xxxxxxxxxxxxx> Ping? > > --- > > Comments, testing, performance measurements, etc. are welcome. > Also tuning of the hash function is welcome. You can see how it is doing by > removing the leading _ in the #define _DEBUG_HASHES in policydb.c. > > security/selinux/ss/mls.c | 18 +++---- > security/selinux/ss/policydb.c | 103 ++++++++++++++++++++++++++++++----------- > security/selinux/ss/policydb.h | 6 -- > 3 files changed, 86 insertions(+), 41 deletions(-) > > diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c > index e6654b5..443ae73 100644 > --- a/security/selinux/ss/mls.c > +++ b/security/selinux/ss/mls.c > @@ -513,7 +513,8 @@ int mls_compute_sid(struct context *scontext, > u32 specified, > struct context *newcontext) > { > - struct range_trans *rtr; > + struct range_trans rtr; > + struct mls_range *r; > > if (!selinux_mls_enabled) > return 0; > @@ -521,15 +522,12 @@ int mls_compute_sid(struct context *scontext, > switch (specified) { > case AVTAB_TRANSITION: > /* Look for a range transition rule. */ > - for (rtr = policydb.range_tr; rtr; rtr = rtr->next) { > - if (rtr->source_type == scontext->type && > - rtr->target_type == tcontext->type && > - rtr->target_class == tclass) { > - /* Set the range from the rule */ > - return mls_range_set(newcontext, > - &rtr->target_range); > - } > - } > + rtr.source_type = scontext->type; > + rtr.target_type = tcontext->type; > + rtr.target_class = tclass; > + r = hashtab_search(policydb.range_tr, &rtr); > + if (r) > + return mls_range_set(newcontext, r); > /* Fallthrough */ > case AVTAB_CHANGE: > if (tclass == policydb.process_class) > diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c > index f036672..5b92c02 100644 > --- a/security/selinux/ss/policydb.c > +++ b/security/selinux/ss/policydb.c > @@ -177,6 +177,21 @@ out_free_role: > goto out; > } > > +static u32 rangetr_hash(struct hashtab *h, const void *k) > +{ > + const struct range_trans *key = k; > + return (key->source_type + (key->target_type << 3) + > + (key->target_class << 5)) & (h->size - 1); > +} > + > +static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2) > +{ > + const struct range_trans *key1 = k1, *key2 = k2; > + return (key1->source_type != key2->source_type || > + key1->target_type != key2->target_type || > + key1->target_class != key2->target_class); > +} > + > /* > * Initialize a policy database structure. > */ > @@ -204,6 +219,10 @@ static int policydb_init(struct policydb *p) > if (rc) > goto out_free_symtab; > > + p->range_tr = hashtab_create(rangetr_hash, rangetr_cmp, 256); > + if (!p->range_tr) > + goto out_free_symtab; > + > ebitmap_init(&p->policycaps); > ebitmap_init(&p->permissive_map); > > @@ -408,6 +427,20 @@ static void symtab_hash_eval(struct symtab *s) > info.slots_used, h->size, info.max_chain_len); > } > } > + > +static void rangetr_hash_eval(struct hashtab *h) > +{ > + struct hashtab_info info; > + > + hashtab_stat(h, &info); > + printk(KERN_DEBUG "SELinux: rangetr: %d entries and %d/%d buckets used, " > + "longest chain length %d\n", h->nel, > + info.slots_used, h->size, info.max_chain_len); > +} > +#else > +static inline void rangetr_hash_eval(struct hashtab *h) > +{ > +} > #endif > > /* > @@ -612,6 +645,17 @@ static int (*destroy_f[SYM_NUM]) (void *key, void *datum, void *datap) = > cat_destroy, > }; > > +static int range_tr_destroy(void *key, void *datum, void *p) > +{ > + struct mls_range *rt = datum; > + kfree(key); > + ebitmap_destroy(&rt->level[0].cat); > + ebitmap_destroy(&rt->level[1].cat); > + kfree(datum); > + cond_resched(); > + return 0; > +} > + > static void ocontext_destroy(struct ocontext *c, int i) > { > context_destroy(&c->context[0]); > @@ -632,7 +676,6 @@ void policydb_destroy(struct policydb *p) > int i; > struct role_allow *ra, *lra = NULL; > struct role_trans *tr, *ltr = NULL; > - struct range_trans *rt, *lrt = NULL; > > for (i = 0; i < SYM_NUM; i++) { > cond_resched(); > @@ -693,20 +736,8 @@ void policydb_destroy(struct policydb *p) > } > kfree(lra); > > - for (rt = p->range_tr; rt; rt = rt->next) { > - cond_resched(); > - if (lrt) { > - ebitmap_destroy(&lrt->target_range.level[0].cat); > - ebitmap_destroy(&lrt->target_range.level[1].cat); > - kfree(lrt); > - } > - lrt = rt; > - } > - if (lrt) { > - ebitmap_destroy(&lrt->target_range.level[0].cat); > - ebitmap_destroy(&lrt->target_range.level[1].cat); > - kfree(lrt); > - } > + hashtab_map(p->range_tr, range_tr_destroy, NULL); > + hashtab_destroy(p->range_tr); > > if (p->type_attr_map) { > for (i = 0; i < p->p_types.nprim; i++) > @@ -1689,7 +1720,8 @@ int policydb_read(struct policydb *p, void *fp) > u32 len, len2, config, nprim, nel, nel2; > char *policydb_str; > struct policydb_compat_info *info; > - struct range_trans *rt, *lrt; > + struct range_trans *rt; > + struct mls_range *r; > > config = 0; > > @@ -2122,44 +2154,61 @@ int policydb_read(struct policydb *p, void *fp) > if (rc < 0) > goto bad; > nel = le32_to_cpu(buf[0]); > - lrt = NULL; > for (i = 0; i < nel; i++) { > rt = kzalloc(sizeof(*rt), GFP_KERNEL); > if (!rt) { > rc = -ENOMEM; > goto bad; > } > - if (lrt) > - lrt->next = rt; > - else > - p->range_tr = rt; > rc = next_entry(buf, fp, (sizeof(u32) * 2)); > - if (rc < 0) > + if (rc < 0) { > + kfree(rt); > goto bad; > + } > rt->source_type = le32_to_cpu(buf[0]); > rt->target_type = le32_to_cpu(buf[1]); > if (new_rangetr) { > rc = next_entry(buf, fp, sizeof(u32)); > - if (rc < 0) > + if (rc < 0) { > + kfree(rt); > goto bad; > + } > rt->target_class = le32_to_cpu(buf[0]); > } else > rt->target_class = p->process_class; > if (!policydb_type_isvalid(p, rt->source_type) || > !policydb_type_isvalid(p, rt->target_type) || > !policydb_class_isvalid(p, rt->target_class)) { > + kfree(rt); > rc = -EINVAL; > goto bad; > } > - rc = mls_read_range_helper(&rt->target_range, fp); > - if (rc) > + r = kzalloc(sizeof(*r), GFP_KERNEL); > + if (!r) { > + kfree(rt); > + rc = -ENOMEM; > goto bad; > - if (!mls_range_isvalid(p, &rt->target_range)) { > + } > + rc = mls_read_range_helper(r, fp); > + if (rc) { > + kfree(rt); > + kfree(r); > + goto bad; > + } > + if (!mls_range_isvalid(p, r)) { > printk(KERN_WARNING "SELinux: rangetrans: invalid range\n"); > + kfree(rt); > + kfree(r); > + goto bad; > + } > + rc = hashtab_insert(p->range_tr, rt, r); > + if (rc) { > + kfree(rt); > + kfree(r); > goto bad; > } > - lrt = rt; > } > + rangetr_hash_eval(p->range_tr); > } > > p->type_attr_map = kmalloc(p->p_types.nprim*sizeof(struct ebitmap), GFP_KERNEL); > diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h > index cdcc570..193736b 100644 > --- a/security/selinux/ss/policydb.h > +++ b/security/selinux/ss/policydb.h > @@ -113,8 +113,6 @@ struct range_trans { > u32 source_type; > u32 target_type; > u32 target_class; > - struct mls_range target_range; > - struct range_trans *next; > }; > > /* Boolean data type */ > @@ -240,8 +238,8 @@ struct policydb { > fixed labeling behavior. */ > struct genfs *genfs; > > - /* range transitions */ > - struct range_trans *range_tr; > + /* range transitions table (range_trans_key -> mls_range) */ > + struct hashtab *range_tr; > > /* type -> attribute reverse mapping */ > struct ebitmap *type_attr_map; > > > -- Stephen Smalley National Security Agency -- This message was distributed to subscribers of the selinux mailing list. 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