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SubjectRe: [RFC][PATCH 7/7] ima: added new LSM conditions in the policy
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On Thursday, April 28, 2011 03:32:38 PM Mimi Zohar wrote:
> On Wed, 2011-04-27 at 14:34 +0200, Roberto Sassu wrote:
> > The new parameters 'fowner_user', 'fowner_role' and 'fowner_type' are new
> > LSM conditions that allow to measure inodes whose opened file descriptor
> > has the label given as a value.
> >
> > Signed-off-by: Roberto Sassu <roberto.sassu@polito.it>
>
> Nice. I really like the 'fowner_' prefix. If you don't object, I'll
> change the ima-appraisal keyword from 'owner' to 'fowner' as well.
>

Hi Mimi

i agree about this change.

Thanks

Roberto Sassu


> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
>
> thanks,
>
> Mimi
>
> > ---
> > Documentation/ABI/testing/ima_policy | 7 ++++-
> > security/integrity/ima/ima.h | 4 +-
> > security/integrity/ima/ima_api.c | 4 +-
> > security/integrity/ima/ima_main.c | 4 +-
> > security/integrity/ima/ima_policy.c | 45 +++++++++++++++++++++++++++++----
> > 5 files changed, 51 insertions(+), 13 deletions(-)
> >
> > diff --git a/Documentation/ABI/testing/ima_policy b/Documentation/ABI/testing/ima_policy
> > index 6cd6dae..ee49345 100644
> > --- a/Documentation/ABI/testing/ima_policy
> > +++ b/Documentation/ABI/testing/ima_policy
> > @@ -18,7 +18,8 @@ Description:
> > condition:= base | lsm
> > base: [[func=] [mask=] [fsmagic=] [uid=]]
> > lsm: [[subj_user=] [subj_role=] [subj_type=]
> > - [obj_user=] [obj_role=] [obj_type=]]
> > + [obj_user=] [obj_role=] [obj_type=]
> > + [fowner_user=] [fowner_role=] [fowner_type=]]
> >
> > base: func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK]
> > mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
> > @@ -46,6 +47,10 @@ Description:
> > all files mmapped executable in file_mmap, and all files
> > open for read by root in do_filp_open.
> >
> > + LSM conditions starting with obj_ refer to security attributes
> > + of inodes while those starting with fowner_ involve file
> > + descriptors.
> > +
> > Examples of LSM specific definitions:
> >
> > SELinux:
> > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> > index 08408bd..3a05625 100644
> > --- a/security/integrity/ima/ima.h
> > +++ b/security/integrity/ima/ima.h
> > @@ -110,7 +110,7 @@ struct ima_iint_cache {
> > };
> >
> > /* LIM API function definitions */
> > -int ima_must_measure(struct inode *inode, int mask, int function);
> > +int ima_must_measure(struct file *file, int mask, int function);
> > int ima_collect_measurement(struct ima_iint_cache *iint, struct file *file);
> > void ima_store_measurement(struct ima_iint_cache *iint, struct file *file,
> > const unsigned char *filename);
> > @@ -128,7 +128,7 @@ struct ima_iint_cache *ima_iint_find(struct inode *inode);
> > /* IMA policy related functions */
> > enum ima_hooks { FILE_CHECK = 1, FILE_MMAP, BPRM_CHECK };
> >
> > -int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask);
> > +int ima_match_policy(struct file *file, enum ima_hooks func, int mask);
> > void ima_init_policy(void);
> > void ima_update_policy(void);
> > ssize_t ima_parse_add_rule(char *);
> > diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c
> > index da36d2c..d815392 100644
> > --- a/security/integrity/ima/ima_api.c
> > +++ b/security/integrity/ima/ima_api.c
> > @@ -108,11 +108,11 @@ err_out:
> > * Return 0 to measure. For matching a DONT_MEASURE policy, no policy,
> > * or other error, return an error code.
> > */
> > -int ima_must_measure(struct inode *inode, int mask, int function)
> > +int ima_must_measure(struct file *file, int mask, int function)
> > {
> > int must_measure;
> >
> > - must_measure = ima_match_policy(inode, function, mask);
> > + must_measure = ima_match_policy(file, function, mask);
> > return must_measure ? 0 : -EACCES;
> > }
> >
> > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> > index 39d66dc..9eaca61 100644
> > --- a/security/integrity/ima/ima_main.c
> > +++ b/security/integrity/ima/ima_main.c
> > @@ -65,7 +65,7 @@ static void ima_rdwr_violation_check(struct file *file)
> > goto out;
> > }
> >
> > - rc = ima_must_measure(inode, MAY_READ, FILE_CHECK);
> > + rc = ima_must_measure(file, MAY_READ, FILE_CHECK);
> > if (rc < 0)
> > goto out;
> >
> > @@ -127,7 +127,7 @@ static int process_measurement(struct file *file, const unsigned char *filename,
> > if (!ima_initialized || !S_ISREG(inode->i_mode))
> > return 0;
> >
> > - rc = ima_must_measure(inode, mask, function);
> > + rc = ima_must_measure(file, mask, function);
> > if (rc != 0)
> > return rc;
> > retry:
> > diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> > index d661afb..115c2e7 100644
> > --- a/security/integrity/ima/ima_policy.c
> > +++ b/security/integrity/ima/ima_policy.c
> > @@ -27,9 +27,10 @@
> >
> > enum ima_action { UNKNOWN = -1, DONT_MEASURE = 0, MEASURE };
> >
> > -#define MAX_LSM_RULES 6
> > +#define MAX_LSM_RULES 9
> > enum lsm_rule_types { LSM_OBJ_USER, LSM_OBJ_ROLE, LSM_OBJ_TYPE,
> > - LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE
> > + LSM_SUBJ_USER, LSM_SUBJ_ROLE, LSM_SUBJ_TYPE,
> > + LSM_FOWNER_USER, LSM_FOWNER_ROLE, LSM_FOWNER_TYPE
> > };
> >
> > struct ima_measure_rule_entry {
> > @@ -96,9 +97,10 @@ __setup("ima_tcb", default_policy_setup);
> > * Returns true on rule match, false on failure.
> > */
> > static bool ima_match_rules(struct ima_measure_rule_entry *rule,
> > - struct inode *inode, enum ima_hooks func, int mask)
> > + struct file *file, enum ima_hooks func, int mask)
> > {
> > struct task_struct *tsk = current;
> > + struct inode *inode = file->f_dentry->d_inode;
> > int i;
> >
> > if ((rule->flags & IMA_FUNC) && rule->func != func)
> > @@ -112,7 +114,7 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
> > return false;
> > for (i = 0; i < MAX_LSM_RULES; i++) {
> > int rc = 0;
> > - u32 osid, sid;
> > + u32 osid, sid, fsid;
> >
> > if (!rule->lsm[i].rule)
> > continue;
> > @@ -137,6 +139,15 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
> > Audit_equal,
> > rule->lsm[i].rule,
> > NULL);
> > + case LSM_FOWNER_USER:
> > + case LSM_FOWNER_ROLE:
> > + case LSM_FOWNER_TYPE:
> > + security_file_getsecid(file, &fsid);
> > + rc = security_filter_rule_match(fsid,
> > + rule->lsm[i].type,
> > + Audit_equal,
> > + rule->lsm[i].rule,
> > + NULL);
> > default:
> > break;
> > }
> > @@ -159,14 +170,14 @@ static bool ima_match_rules(struct ima_measure_rule_entry *rule,
> > * as elements in the list are never deleted, nor does the list
> > * change.)
> > */
> > -int ima_match_policy(struct inode *inode, enum ima_hooks func, int mask)
> > +int ima_match_policy(struct file *file, enum ima_hooks func, int mask)
> > {
> > struct ima_measure_rule_entry *entry;
> >
> > list_for_each_entry(entry, ima_measure, list) {
> > bool rc;
> >
> > - rc = ima_match_rules(entry, inode, func, mask);
> > + rc = ima_match_rules(entry, file, func, mask);
> > if (rc)
> > return entry->action;
> > }
> > @@ -222,6 +233,7 @@ enum {
> > Opt_measure = 1, Opt_dont_measure,
> > Opt_obj_user, Opt_obj_role, Opt_obj_type,
> > Opt_subj_user, Opt_subj_role, Opt_subj_type,
> > + Opt_fowner_user, Opt_fowner_role, Opt_fowner_type,
> > Opt_func, Opt_mask, Opt_fsmagic, Opt_uid
> > };
> >
> > @@ -234,6 +246,9 @@ static match_table_t policy_tokens = {
> > {Opt_subj_user, "subj_user=%s"},
> > {Opt_subj_role, "subj_role=%s"},
> > {Opt_subj_type, "subj_type=%s"},
> > + {Opt_fowner_user, "fowner_user=%s"},
> > + {Opt_fowner_role, "fowner_role=%s"},
> > + {Opt_fowner_type, "fowner_type=%s"},
> > {Opt_func, "func=%s"},
> > {Opt_mask, "mask=%s"},
> > {Opt_fsmagic, "fsmagic=%s"},
> > @@ -407,6 +422,24 @@ static int ima_parse_rule(char *rule, struct ima_measure_rule_entry *entry)
> > LSM_SUBJ_TYPE,
> > AUDIT_SUBJ_TYPE);
> > break;
> > + case Opt_fowner_user:
> > + ima_log_string(ab, "fowner_user", args[0].from);
> > + result = ima_lsm_rule_init(entry, args[0].from,
> > + LSM_FOWNER_USER,
> > + AUDIT_SUBJ_USER);
> > + break;
> > + case Opt_fowner_role:
> > + ima_log_string(ab, "fowner_role", args[0].from);
> > + result = ima_lsm_rule_init(entry, args[0].from,
> > + LSM_FOWNER_ROLE,
> > + AUDIT_SUBJ_ROLE);
> > + break;
> > + case Opt_fowner_type:
> > + ima_log_string(ab, "fowner_type", args[0].from);
> > + result = ima_lsm_rule_init(entry, args[0].from,
> > + LSM_FOWNER_TYPE,
> > + AUDIT_SUBJ_TYPE);
> > + break;
> > case Opt_err:
> > ima_log_string(ab, "UNKNOWN", p);
> > result = -EINVAL;
>
>
>


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