From 6371dcd36f649d9d07823f31400618155a20dde1 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Thu, 29 Jul 2010 23:02:34 -0400 Subject: [PATCH] selinux: convert the policy type_attr_map to flex_array Current selinux policy can have over 3000 types. The type_attr_map in policy is an array sized by the number of types times sizeof(struct ebitmap) (12 on x86_64). Basic math tells us the array is going to be of length 3000 x 12 = 36,000 bytes. The largest 'safe' allocation on a long running system is 16k. Most of the time a 32k allocation will work. But on long running systems a 64k allocation (what we need) can fail quite regularly. In order to deal with this I am converting the type_attr_map to use flex_arrays. Let the library code deal with breaking this into PAGE_SIZE pieces. -v2 rework some of the if(!obj) BUG() to be BUG_ON(!obj) drop flex_array_put() calls and just use a _get() object directly -v3 make apply to James' tree (drop the policydb_write changes) Signed-off-by: Eric Paris Acked-by: Stephen D. Smalley Signed-off-by: James Morris --- security/selinux/ss/policydb.c | 41 +++++++++++++++++++++++++--------- security/selinux/ss/policydb.h | 4 +++- security/selinux/ss/services.c | 7 ++++-- 3 files changed, 39 insertions(+), 13 deletions(-) diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c index 674ddfe0ba03..3a29704be8ce 100644 --- a/security/selinux/ss/policydb.c +++ b/security/selinux/ss/policydb.c @@ -31,6 +31,7 @@ #include #include #include +#include #include "security.h" #include "policydb.h" @@ -739,11 +740,17 @@ void policydb_destroy(struct policydb *p) 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++) - ebitmap_destroy(&p->type_attr_map[i]); + if (p->type_attr_map_array) { + for (i = 0; i < p->p_types.nprim; i++) { + struct ebitmap *e; + + e = flex_array_get(p->type_attr_map_array, i); + if (!e) + continue; + ebitmap_destroy(e); + } + flex_array_free(p->type_attr_map_array); } - kfree(p->type_attr_map); ebitmap_destroy(&p->policycaps); ebitmap_destroy(&p->permissive_map); @@ -2257,19 +2264,33 @@ int policydb_read(struct policydb *p, void *fp) if (rc) goto bad; - p->type_attr_map = kmalloc(p->p_types.nprim * sizeof(struct ebitmap), GFP_KERNEL); - if (!p->type_attr_map) + rc = -ENOMEM; + p->type_attr_map_array = flex_array_alloc(sizeof(struct ebitmap), + p->p_types.nprim, + GFP_KERNEL | __GFP_ZERO); + if (!p->type_attr_map_array) + goto bad; + + /* preallocate so we don't have to worry about the put ever failing */ + rc = flex_array_prealloc(p->type_attr_map_array, 0, p->p_types.nprim - 1, + GFP_KERNEL | __GFP_ZERO); + if (rc) goto bad; for (i = 0; i < p->p_types.nprim; i++) { - ebitmap_init(&p->type_attr_map[i]); + struct ebitmap *e = flex_array_get(p->type_attr_map_array, i); + + BUG_ON(!e); + ebitmap_init(e); if (p->policyvers >= POLICYDB_VERSION_AVTAB) { - if (ebitmap_read(&p->type_attr_map[i], fp)) + rc = ebitmap_read(e, fp); + if (rc) goto bad; } /* add the type itself as the degenerate case */ - if (ebitmap_set_bit(&p->type_attr_map[i], i, 1)) - goto bad; + rc = ebitmap_set_bit(e, i, 1); + if (rc) + goto bad; } rc = policydb_bounds_sanity_check(p); diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h index 26d9adf8542b..310e94442cb8 100644 --- a/security/selinux/ss/policydb.h +++ b/security/selinux/ss/policydb.h @@ -24,6 +24,8 @@ #ifndef _SS_POLICYDB_H_ #define _SS_POLICYDB_H_ +#include + #include "symtab.h" #include "avtab.h" #include "sidtab.h" @@ -246,7 +248,7 @@ struct policydb { struct hashtab *range_tr; /* type -> attribute reverse mapping */ - struct ebitmap *type_attr_map; + struct flex_array *type_attr_map_array; struct ebitmap policycaps; diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c index 1de60ce90d9a..9ea2feca3cd4 100644 --- a/security/selinux/ss/services.c +++ b/security/selinux/ss/services.c @@ -50,6 +50,7 @@ #include #include #include +#include #include #include "flask.h" @@ -626,8 +627,10 @@ static void context_struct_compute_av(struct context *scontext, */ avkey.target_class = tclass; avkey.specified = AVTAB_AV; - sattr = &policydb.type_attr_map[scontext->type - 1]; - tattr = &policydb.type_attr_map[tcontext->type - 1]; + sattr = flex_array_get(policydb.type_attr_map_array, scontext->type - 1); + BUG_ON(!sattr); + tattr = flex_array_get(policydb.type_attr_map_array, tcontext->type - 1); + BUG_ON(!tattr); ebitmap_for_each_positive_bit(sattr, snode, i) { ebitmap_for_each_positive_bit(tattr, tnode, j) { avkey.source_type = i + 1; -- GitLab