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author | KaiGai Kohei <kaigai@ak.jp.nec.com> | 2007-09-29 02:20:55 +0900 |
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committer | James Morris <jmorris@namei.org> | 2007-10-17 08:59:34 +1000 |
commit | 9fe79ad1e43d236bbbb8edb3cf634356de714c79 (patch) | |
tree | 91149cefa28baf692eb55f88f8c544a33e9126df /security/selinux/ss/mls.c | |
parent | 3f12070e27b4a213d62607d2bff139793089a77d (diff) | |
download | linux-9fe79ad1e43d236bbbb8edb3cf634356de714c79.tar.gz linux-9fe79ad1e43d236bbbb8edb3cf634356de714c79.tar.bz2 linux-9fe79ad1e43d236bbbb8edb3cf634356de714c79.zip |
SELinux: improve performance when AVC misses.
* We add ebitmap_for_each_positive_bit() which enables to walk on
any positive bit on the given ebitmap, to improve its performance
using common bit-operations defined in linux/bitops.h.
In the previous version, this logic was implemented using a combination
of ebitmap_for_each_bit() and ebitmap_node_get_bit(), but is was worse
in performance aspect.
This logic is most frequestly used to compute a new AVC entry,
so this patch can improve SELinux performance when AVC misses are happen.
* struct ebitmap_node is redefined as an array of "unsigned long", to get
suitable for using find_next_bit() which is fasted than iteration of
shift and logical operation, and to maximize memory usage allocated
from general purpose slab.
* Any ebitmap_for_each_bit() are repleced by the new implementation
in ss/service.c and ss/mls.c. Some of related implementation are
changed, however, there is no incompatibility with the previous
version.
* The width of any new line are less or equal than 80-chars.
The following benchmark shows the effect of this patch, when we
access many files which have different security context one after
another. The number is more than /selinux/avc/cache_threshold, so
any access always causes AVC misses.
selinux-2.6 selinux-2.6-ebitmap
AVG: 22.763 [s] 8.750 [s]
STD: 0.265 0.019
------------------------------------------
1st: 22.558 [s] 8.786 [s]
2nd: 22.458 [s] 8.750 [s]
3rd: 22.478 [s] 8.754 [s]
4th: 22.724 [s] 8.745 [s]
5th: 22.918 [s] 8.748 [s]
6th: 22.905 [s] 8.764 [s]
7th: 23.238 [s] 8.726 [s]
8th: 22.822 [s] 8.729 [s]
Signed-off-by: KaiGai Kohei <kaigai@ak.jp.nec.com>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/selinux/ss/mls.c')
-rw-r--r-- | security/selinux/ss/mls.c | 156 |
1 files changed, 75 insertions, 81 deletions
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c index 4a8bab2f3c71..9a11deaaa9e7 100644 --- a/security/selinux/ss/mls.c +++ b/security/selinux/ss/mls.c @@ -34,7 +34,9 @@ */ int mls_compute_context_len(struct context * context) { - int i, l, len, range; + int i, l, len, head, prev; + char *nm; + struct ebitmap *e; struct ebitmap_node *node; if (!selinux_mls_enabled) @@ -42,31 +44,33 @@ int mls_compute_context_len(struct context * context) len = 1; /* for the beginning ":" */ for (l = 0; l < 2; l++) { - range = 0; - len += strlen(policydb.p_sens_val_to_name[context->range.level[l].sens - 1]); - - ebitmap_for_each_bit(&context->range.level[l].cat, node, i) { - if (ebitmap_node_get_bit(node, i)) { - if (range) { - range++; - continue; - } + int index_sens = context->range.level[l].sens; + len += strlen(policydb.p_sens_val_to_name[index_sens - 1]); - len += strlen(policydb.p_cat_val_to_name[i]) + 1; - range++; - } else { - if (range > 1) - len += strlen(policydb.p_cat_val_to_name[i - 1]) + 1; - range = 0; + /* categories */ + head = -2; + prev = -2; + e = &context->range.level[l].cat; + ebitmap_for_each_positive_bit(e, node, i) { + if (i - prev > 1) { + /* one or more negative bits are skipped */ + if (head != prev) { + nm = policydb.p_cat_val_to_name[prev]; + len += strlen(nm) + 1; + } + nm = policydb.p_cat_val_to_name[i]; + len += strlen(nm) + 1; + head = i; } + prev = i; + } + if (prev != head) { + nm = policydb.p_cat_val_to_name[prev]; + len += strlen(nm) + 1; } - /* Handle case where last category is the end of range */ - if (range > 1) - len += strlen(policydb.p_cat_val_to_name[i - 1]) + 1; - if (l == 0) { if (mls_level_eq(&context->range.level[0], - &context->range.level[1])) + &context->range.level[1])) break; else len++; @@ -84,8 +88,9 @@ int mls_compute_context_len(struct context * context) void mls_sid_to_context(struct context *context, char **scontext) { - char *scontextp; - int i, l, range, wrote_sep; + char *scontextp, *nm; + int i, l, head, prev; + struct ebitmap *e; struct ebitmap_node *node; if (!selinux_mls_enabled) @@ -97,61 +102,54 @@ void mls_sid_to_context(struct context *context, scontextp++; for (l = 0; l < 2; l++) { - range = 0; - wrote_sep = 0; strcpy(scontextp, policydb.p_sens_val_to_name[context->range.level[l].sens - 1]); - scontextp += strlen(policydb.p_sens_val_to_name[context->range.level[l].sens - 1]); + scontextp += strlen(scontextp); /* categories */ - ebitmap_for_each_bit(&context->range.level[l].cat, node, i) { - if (ebitmap_node_get_bit(node, i)) { - if (range) { - range++; - continue; - } - - if (!wrote_sep) { - *scontextp++ = ':'; - wrote_sep = 1; - } else - *scontextp++ = ','; - strcpy(scontextp, policydb.p_cat_val_to_name[i]); - scontextp += strlen(policydb.p_cat_val_to_name[i]); - range++; - } else { - if (range > 1) { - if (range > 2) + head = -2; + prev = -2; + e = &context->range.level[l].cat; + ebitmap_for_each_positive_bit(e, node, i) { + if (i - prev > 1) { + /* one or more negative bits are skipped */ + if (prev != head) { + if (prev - head > 1) *scontextp++ = '.'; else *scontextp++ = ','; - - strcpy(scontextp, policydb.p_cat_val_to_name[i - 1]); - scontextp += strlen(policydb.p_cat_val_to_name[i - 1]); + nm = policydb.p_cat_val_to_name[prev]; + strcpy(scontextp, nm); + scontextp += strlen(nm); } - range = 0; + if (prev < 0) + *scontextp++ = ':'; + else + *scontextp++ = ','; + nm = policydb.p_cat_val_to_name[i]; + strcpy(scontextp, nm); + scontextp += strlen(nm); + head = i; } + prev = i; } - /* Handle case where last category is the end of range */ - if (range > 1) { - if (range > 2) + if (prev != head) { + if (prev - head > 1) *scontextp++ = '.'; else *scontextp++ = ','; - - strcpy(scontextp, policydb.p_cat_val_to_name[i - 1]); - scontextp += strlen(policydb.p_cat_val_to_name[i - 1]); + nm = policydb.p_cat_val_to_name[prev]; + strcpy(scontextp, nm); + scontextp += strlen(nm); } if (l == 0) { if (mls_level_eq(&context->range.level[0], &context->range.level[1])) break; - else { - *scontextp = '-'; - scontextp++; - } + else + *scontextp++ = '-'; } } @@ -190,17 +188,15 @@ int mls_context_isvalid(struct policydb *p, struct context *c) if (!levdatum) return 0; - ebitmap_for_each_bit(&c->range.level[l].cat, node, i) { - if (ebitmap_node_get_bit(node, i)) { - if (i > p->p_cats.nprim) - return 0; - if (!ebitmap_get_bit(&levdatum->level->cat, i)) - /* - * Category may not be associated with - * sensitivity in low level. - */ - return 0; - } + ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) { + if (i > p->p_cats.nprim) + return 0; + if (!ebitmap_get_bit(&levdatum->level->cat, i)) + /* + * Category may not be associated with + * sensitivity in low level. + */ + return 0; } } @@ -485,18 +481,16 @@ int mls_convert_context(struct policydb *oldp, c->range.level[l].sens = levdatum->level->sens; ebitmap_init(&bitmap); - ebitmap_for_each_bit(&c->range.level[l].cat, node, i) { - if (ebitmap_node_get_bit(node, i)) { - int rc; - - catdatum = hashtab_search(newp->p_cats.table, - oldp->p_cat_val_to_name[i]); - if (!catdatum) - return -EINVAL; - rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1); - if (rc) - return rc; - } + ebitmap_for_each_positive_bit(&c->range.level[l].cat, node, i) { + int rc; + + catdatum = hashtab_search(newp->p_cats.table, + oldp->p_cat_val_to_name[i]); + if (!catdatum) + return -EINVAL; + rc = ebitmap_set_bit(&bitmap, catdatum->value - 1, 1); + if (rc) + return rc; } ebitmap_destroy(&c->range.level[l].cat); c->range.level[l].cat = bitmap; |