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[PATCH] selinux: Reduce memory use by avtab
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This patch improves memory use by SELinux by both reducing the avtab node
size and reducing the number of avtab nodes.  The memory savings are
substantial, e.g.  on a 64-bit system after boot, James Morris reported the
following data for the targeted and strict policies:

            #objs  objsize   kernmem
Targeted:
  Before:  237888       40     9.1MB
  After:    19968       24     468KB

Strict:
  Before:  571680       40   21.81MB
  After:   221052       24    5.06MB

The improvement in memory use comes at a cost in the speed of security
server computations of access vectors, but these computations are only
required on AVC cache misses, and performance measurements by James Morris
using a number of benchmarks have shown that the change does not cause any
significant degradation.

Note that a rebuilt policy via an updated policy toolchain
(libsepol/checkpolicy) is required in order to gain the full benefits of
this patch, although some memory savings benefits are immediately applied
even to older policies (in particular, the reduction in avtab node size).
Sources for the updated toolchain are presently available from the
sourceforge CVS tree (http://sourceforge.net/cvs/?group_id=21266), and
tarballs are available from http://www.flux.utah.edu/~sds.

Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Stephen Smalley authored and Linus Torvalds committed Sep 5, 2005
1 parent 720d6c2 commit 782ebb9
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Showing 9 changed files with 400 additions and 235 deletions.
3 changes: 2 additions & 1 deletion security/selinux/include/security.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,10 +23,11 @@
#define POLICYDB_VERSION_NLCLASS 18
#define POLICYDB_VERSION_VALIDATETRANS 19
#define POLICYDB_VERSION_MLS 19
#define POLICYDB_VERSION_AVTAB 20

/* Range of policy versions we understand*/
#define POLICYDB_VERSION_MIN POLICYDB_VERSION_BASE
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_MLS
#define POLICYDB_VERSION_MAX POLICYDB_VERSION_AVTAB

#ifdef CONFIG_SECURITY_SELINUX_BOOTPARAM
extern int selinux_enabled;
Expand Down
192 changes: 123 additions & 69 deletions security/selinux/ss/avtab.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,7 @@ static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_dat
{
int hvalue;
struct avtab_node *prev, *cur, *newnode;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);

if (!h)
return -EINVAL;
Expand All @@ -69,7 +70,7 @@ static int avtab_insert(struct avtab *h, struct avtab_key *key, struct avtab_dat
if (key->source_type == cur->key.source_type &&
key->target_type == cur->key.target_type &&
key->target_class == cur->key.target_class &&
(datum->specified & cur->datum.specified))
(specified & cur->key.specified))
return -EEXIST;
if (key->source_type < cur->key.source_type)
break;
Expand Down Expand Up @@ -98,6 +99,7 @@ avtab_insert_nonunique(struct avtab * h, struct avtab_key * key, struct avtab_da
{
int hvalue;
struct avtab_node *prev, *cur, *newnode;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);

if (!h)
return NULL;
Expand All @@ -108,7 +110,7 @@ avtab_insert_nonunique(struct avtab * h, struct avtab_key * key, struct avtab_da
if (key->source_type == cur->key.source_type &&
key->target_type == cur->key.target_type &&
key->target_class == cur->key.target_class &&
(datum->specified & cur->datum.specified))
(specified & cur->key.specified))
break;
if (key->source_type < cur->key.source_type)
break;
Expand All @@ -125,10 +127,11 @@ avtab_insert_nonunique(struct avtab * h, struct avtab_key * key, struct avtab_da
return newnode;
}

struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key, int specified)
struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key)
{
int hvalue;
struct avtab_node *cur;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);

if (!h)
return NULL;
Expand All @@ -138,7 +141,7 @@ struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key, int spe
if (key->source_type == cur->key.source_type &&
key->target_type == cur->key.target_type &&
key->target_class == cur->key.target_class &&
(specified & cur->datum.specified))
(specified & cur->key.specified))
return &cur->datum;

if (key->source_type < cur->key.source_type)
Expand All @@ -159,10 +162,11 @@ struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *key, int spe
* conjunction with avtab_search_next_node()
*/
struct avtab_node*
avtab_search_node(struct avtab *h, struct avtab_key *key, int specified)
avtab_search_node(struct avtab *h, struct avtab_key *key)
{
int hvalue;
struct avtab_node *cur;
u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);

if (!h)
return NULL;
Expand All @@ -172,7 +176,7 @@ avtab_search_node(struct avtab *h, struct avtab_key *key, int specified)
if (key->source_type == cur->key.source_type &&
key->target_type == cur->key.target_type &&
key->target_class == cur->key.target_class &&
(specified & cur->datum.specified))
(specified & cur->key.specified))
return cur;

if (key->source_type < cur->key.source_type)
Expand All @@ -196,11 +200,12 @@ avtab_search_node_next(struct avtab_node *node, int specified)
if (!node)
return NULL;

specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD);
for (cur = node->next; cur; cur = cur->next) {
if (node->key.source_type == cur->key.source_type &&
node->key.target_type == cur->key.target_type &&
node->key.target_class == cur->key.target_class &&
(specified & cur->datum.specified))
(specified & cur->key.specified))
return cur;

if (node->key.source_type < cur->key.source_type)
Expand Down Expand Up @@ -278,75 +283,126 @@ void avtab_hash_eval(struct avtab *h, char *tag)
max_chain_len);
}

int avtab_read_item(void *fp, struct avtab_datum *avdatum, struct avtab_key *avkey)
static uint16_t spec_order[] = {
AVTAB_ALLOWED,
AVTAB_AUDITDENY,
AVTAB_AUDITALLOW,
AVTAB_TRANSITION,
AVTAB_CHANGE,
AVTAB_MEMBER
};

int avtab_read_item(void *fp, u32 vers, struct avtab *a,
int (*insertf)(struct avtab *a, struct avtab_key *k,
struct avtab_datum *d, void *p),
void *p)
{
u32 buf[7];
u32 items, items2;
int rc;
u16 buf16[4], enabled;
u32 buf32[7], items, items2, val;
struct avtab_key key;
struct avtab_datum datum;
int i, rc;

memset(&key, 0, sizeof(struct avtab_key));
memset(&datum, 0, sizeof(struct avtab_datum));

if (vers < POLICYDB_VERSION_AVTAB) {
rc = next_entry(buf32, fp, sizeof(u32));
if (rc < 0) {
printk(KERN_ERR "security: avtab: truncated entry\n");
return -1;
}
items2 = le32_to_cpu(buf32[0]);
if (items2 > ARRAY_SIZE(buf32)) {
printk(KERN_ERR "security: avtab: entry overflow\n");
return -1;

memset(avkey, 0, sizeof(struct avtab_key));
memset(avdatum, 0, sizeof(struct avtab_datum));
}
rc = next_entry(buf32, fp, sizeof(u32)*items2);
if (rc < 0) {
printk(KERN_ERR "security: avtab: truncated entry\n");
return -1;
}
items = 0;

rc = next_entry(buf, fp, sizeof(u32));
if (rc < 0) {
printk(KERN_ERR "security: avtab: truncated entry\n");
goto bad;
}
items2 = le32_to_cpu(buf[0]);
if (items2 > ARRAY_SIZE(buf)) {
printk(KERN_ERR "security: avtab: entry overflow\n");
goto bad;
val = le32_to_cpu(buf32[items++]);
key.source_type = (u16)val;
if (key.source_type != val) {
printk("security: avtab: truncated source type\n");
return -1;
}
val = le32_to_cpu(buf32[items++]);
key.target_type = (u16)val;
if (key.target_type != val) {
printk("security: avtab: truncated target type\n");
return -1;
}
val = le32_to_cpu(buf32[items++]);
key.target_class = (u16)val;
if (key.target_class != val) {
printk("security: avtab: truncated target class\n");
return -1;
}

val = le32_to_cpu(buf32[items++]);
enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0;

if (!(val & (AVTAB_AV | AVTAB_TYPE))) {
printk("security: avtab: null entry\n");
return -1;
}
if ((val & AVTAB_AV) &&
(val & AVTAB_TYPE)) {
printk("security: avtab: entry has both access vectors and types\n");
return -1;
}

for (i = 0; i < sizeof(spec_order)/sizeof(u16); i++) {
if (val & spec_order[i]) {
key.specified = spec_order[i] | enabled;
datum.data = le32_to_cpu(buf32[items++]);
rc = insertf(a, &key, &datum, p);
if (rc) return rc;
}
}

if (items != items2) {
printk("security: avtab: entry only had %d items, expected %d\n", items2, items);
return -1;
}
return 0;
}
rc = next_entry(buf, fp, sizeof(u32)*items2);

rc = next_entry(buf16, fp, sizeof(u16)*4);
if (rc < 0) {
printk(KERN_ERR "security: avtab: truncated entry\n");
goto bad;
printk("security: avtab: truncated entry\n");
return -1;
}

items = 0;
avkey->source_type = le32_to_cpu(buf[items++]);
avkey->target_type = le32_to_cpu(buf[items++]);
avkey->target_class = le32_to_cpu(buf[items++]);
avdatum->specified = le32_to_cpu(buf[items++]);
if (!(avdatum->specified & (AVTAB_AV | AVTAB_TYPE))) {
printk(KERN_ERR "security: avtab: null entry\n");
goto bad;
}
if ((avdatum->specified & AVTAB_AV) &&
(avdatum->specified & AVTAB_TYPE)) {
printk(KERN_ERR "security: avtab: entry has both access vectors and types\n");
goto bad;
}
if (avdatum->specified & AVTAB_AV) {
if (avdatum->specified & AVTAB_ALLOWED)
avtab_allowed(avdatum) = le32_to_cpu(buf[items++]);
if (avdatum->specified & AVTAB_AUDITDENY)
avtab_auditdeny(avdatum) = le32_to_cpu(buf[items++]);
if (avdatum->specified & AVTAB_AUDITALLOW)
avtab_auditallow(avdatum) = le32_to_cpu(buf[items++]);
} else {
if (avdatum->specified & AVTAB_TRANSITION)
avtab_transition(avdatum) = le32_to_cpu(buf[items++]);
if (avdatum->specified & AVTAB_CHANGE)
avtab_change(avdatum) = le32_to_cpu(buf[items++]);
if (avdatum->specified & AVTAB_MEMBER)
avtab_member(avdatum) = le32_to_cpu(buf[items++]);
}
if (items != items2) {
printk(KERN_ERR "security: avtab: entry only had %d items, expected %d\n",
items2, items);
goto bad;
key.source_type = le16_to_cpu(buf16[items++]);
key.target_type = le16_to_cpu(buf16[items++]);
key.target_class = le16_to_cpu(buf16[items++]);
key.specified = le16_to_cpu(buf16[items++]);

rc = next_entry(buf32, fp, sizeof(u32));
if (rc < 0) {
printk("security: avtab: truncated entry\n");
return -1;
}
datum.data = le32_to_cpu(*buf32);
return insertf(a, &key, &datum, p);
}

return 0;
bad:
return -1;
static int avtab_insertf(struct avtab *a, struct avtab_key *k,
struct avtab_datum *d, void *p)
{
return avtab_insert(a, k, d);
}

int avtab_read(struct avtab *a, void *fp, u32 config)
int avtab_read(struct avtab *a, void *fp, u32 vers)
{
int rc;
struct avtab_key avkey;
struct avtab_datum avdatum;
u32 buf[1];
u32 nel, i;

Expand All @@ -363,16 +419,14 @@ int avtab_read(struct avtab *a, void *fp, u32 config)
goto bad;
}
for (i = 0; i < nel; i++) {
if (avtab_read_item(fp, &avdatum, &avkey)) {
rc = -EINVAL;
goto bad;
}
rc = avtab_insert(a, &avkey, &avdatum);
rc = avtab_read_item(fp,vers, a, avtab_insertf, NULL);
if (rc) {
if (rc == -ENOMEM)
printk(KERN_ERR "security: avtab: out of memory\n");
if (rc == -EEXIST)
else if (rc == -EEXIST)
printk(KERN_ERR "security: avtab: duplicate entry\n");
else
rc = -EINVAL;
goto bad;
}
}
Expand Down
37 changes: 18 additions & 19 deletions security/selinux/ss/avtab.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,12 +21,9 @@
#define _SS_AVTAB_H_

struct avtab_key {
u32 source_type; /* source type */
u32 target_type; /* target type */
u32 target_class; /* target object class */
};

struct avtab_datum {
u16 source_type; /* source type */
u16 target_type; /* target type */
u16 target_class; /* target object class */
#define AVTAB_ALLOWED 1
#define AVTAB_AUDITALLOW 2
#define AVTAB_AUDITDENY 4
Expand All @@ -35,15 +32,13 @@ struct avtab_datum {
#define AVTAB_MEMBER 32
#define AVTAB_CHANGE 64
#define AVTAB_TYPE (AVTAB_TRANSITION | AVTAB_MEMBER | AVTAB_CHANGE)
#define AVTAB_ENABLED 0x80000000 /* reserved for used in cond_avtab */
u32 specified; /* what fields are specified */
u32 data[3]; /* access vectors or types */
#define avtab_allowed(x) (x)->data[0]
#define avtab_auditdeny(x) (x)->data[1]
#define avtab_auditallow(x) (x)->data[2]
#define avtab_transition(x) (x)->data[0]
#define avtab_change(x) (x)->data[1]
#define avtab_member(x) (x)->data[2]
#define AVTAB_ENABLED_OLD 0x80000000 /* reserved for used in cond_avtab */
#define AVTAB_ENABLED 0x8000 /* reserved for used in cond_avtab */
u16 specified; /* what field is specified */
};

struct avtab_datum {
u32 data; /* access vector or type value */
};

struct avtab_node {
Expand All @@ -58,17 +53,21 @@ struct avtab {
};

int avtab_init(struct avtab *);
struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k, int specified);
struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k);
void avtab_destroy(struct avtab *h);
void avtab_hash_eval(struct avtab *h, char *tag);

int avtab_read_item(void *fp, struct avtab_datum *avdatum, struct avtab_key *avkey);
int avtab_read(struct avtab *a, void *fp, u32 config);
int avtab_read_item(void *fp, uint32_t vers, struct avtab *a,
int (*insert)(struct avtab *a, struct avtab_key *k,
struct avtab_datum *d, void *p),
void *p);

int avtab_read(struct avtab *a, void *fp, u32 vers);

struct avtab_node *avtab_insert_nonunique(struct avtab *h, struct avtab_key *key,
struct avtab_datum *datum);

struct avtab_node *avtab_search_node(struct avtab *h, struct avtab_key *key, int specified);
struct avtab_node *avtab_search_node(struct avtab *h, struct avtab_key *key);

struct avtab_node *avtab_search_node_next(struct avtab_node *node, int specified);

Expand Down
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