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    SubjectRe: [RFC][PATCH 7/7] ima: added new LSM conditions in the policy
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    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.

    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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