diff options
| author | Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> | 2010-02-11 01:43:20 +0100 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2010-02-14 23:00:21 +0100 |
| commit | ec8e6a4e062e2edebef91e930c20572c9f4c0dda (patch) | |
| tree | 1c48fb2aa2220b3bdc138e0fb33e1ac632d0dffe /security/tomoyo/tomoyo.c | |
| parent | TOMOYO: Merge headers. (diff) | |
| download | linux-ec8e6a4e062e2edebef91e930c20572c9f4c0dda.tar.xz linux-ec8e6a4e062e2edebef91e930c20572c9f4c0dda.zip | |
TOMOYO: Add refcounter on domain structure.
Add refcounter to "struct tomoyo_domain_info" since garbage collector needs to
determine whether this struct is referred by "struct cred"->security or not.
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/tomoyo/tomoyo.c')
| -rw-r--r-- | security/tomoyo/tomoyo.c | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/security/tomoyo/tomoyo.c b/security/tomoyo/tomoyo.c index 8a0988dade79..87e82bfeac2f 100644 --- a/security/tomoyo/tomoyo.c +++ b/security/tomoyo/tomoyo.c @@ -21,21 +21,23 @@ static int tomoyo_cred_alloc_blank(struct cred *new, gfp_t gfp) static int tomoyo_cred_prepare(struct cred *new, const struct cred *old, gfp_t gfp) { - /* - * Since "struct tomoyo_domain_info *" is a sharable pointer, - * we don't need to duplicate. - */ - new->security = old->security; + struct tomoyo_domain_info *domain = old->security; + new->security = domain; + if (domain) + atomic_inc(&domain->users); return 0; } static void tomoyo_cred_transfer(struct cred *new, const struct cred *old) { - /* - * Since "struct tomoyo_domain_info *" is a sharable pointer, - * we don't need to duplicate. - */ - new->security = old->security; + tomoyo_cred_prepare(new, old, 0); +} + +static void tomoyo_cred_free(struct cred *cred) +{ + struct tomoyo_domain_info *domain = cred->security; + if (domain) + atomic_dec(&domain->users); } static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) @@ -59,6 +61,14 @@ static int tomoyo_bprm_set_creds(struct linux_binprm *bprm) if (!tomoyo_policy_loaded) tomoyo_load_policy(bprm->filename); /* + * Release reference to "struct tomoyo_domain_info" stored inside + * "bprm->cred->security". New reference to "struct tomoyo_domain_info" + * stored inside "bprm->cred->security" will be acquired later inside + * tomoyo_find_next_domain(). + */ + atomic_dec(&((struct tomoyo_domain_info *) + bprm->cred->security)->users); + /* * Tell tomoyo_bprm_check_security() is called for the first time of an * execve operation. */ @@ -75,12 +85,6 @@ static int tomoyo_bprm_check_security(struct linux_binprm *bprm) * using current domain. */ if (!domain) { - /* - * We will need to protect whole execve() operation when GC - * starts kfree()ing "struct tomoyo_domain_info" because - * bprm->cred->security points to "struct tomoyo_domain_info" - * but "struct tomoyo_domain_info" does not have a refcounter. - */ const int idx = tomoyo_read_lock(); const int err = tomoyo_find_next_domain(bprm); tomoyo_read_unlock(idx); @@ -265,6 +269,7 @@ static struct security_operations tomoyo_security_ops = { .cred_alloc_blank = tomoyo_cred_alloc_blank, .cred_prepare = tomoyo_cred_prepare, .cred_transfer = tomoyo_cred_transfer, + .cred_free = tomoyo_cred_free, .bprm_set_creds = tomoyo_bprm_set_creds, .bprm_check_security = tomoyo_bprm_check_security, .file_fcntl = tomoyo_file_fcntl, |