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Diffstat (limited to 'security/smack/smack_lsm.c')
-rw-r--r--security/smack/smack_lsm.c85
1 files changed, 49 insertions, 36 deletions
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index 123a499ded37..92cb71507f5b 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -1110,38 +1110,6 @@ static int smack_file_fcntl(struct file *file, unsigned int cmd,
}
/**
- * smk_mmap_list_check - the mmap check
- * @sub: subject label
- * @obj: object label
- * @access: access mode
- * @local: the task specific rule list
- *
- * Returns 0 if acces is permitted, -EACCES otherwise
- */
-static int smk_mmap_list_check(char *sub, char *obj, int access,
- struct list_head *local)
-{
- int may;
-
- /*
- * If there is not a global rule that
- * allows access say no.
- */
- may = smk_access_entry(sub, obj, &smack_rule_list);
- if (may == -ENOENT || (may & access) != access)
- return -EACCES;
- /*
- * If there is a task local rule that
- * denies access say no.
- */
- may = smk_access_entry(sub, obj, local);
- if (may != -ENOENT && (may & access) != access)
- return -EACCES;
-
- return 0;
-}
-
-/**
* smack_file_mmap :
* Check permissions for a mmap operation. The @file may be NULL, e.g.
* if mapping anonymous memory.
@@ -1160,8 +1128,12 @@ static int smack_file_mmap(struct file *file,
struct task_smack *tsp;
char *sp;
char *msmack;
+ char *osmack;
struct inode_smack *isp;
struct dentry *dp;
+ int may;
+ int mmay;
+ int tmay;
int rc;
/* do DAC check on address space usage */
@@ -1199,16 +1171,57 @@ static int smack_file_mmap(struct file *file,
list_for_each_entry_rcu(srp, &smack_rule_list, list) {
if (srp->smk_subject != sp)
continue;
+
+ osmack = srp->smk_object;
/*
* Matching labels always allows access.
*/
- if (msmack == srp->smk_object)
+ if (msmack == osmack)
+ continue;
+ /*
+ * If there is a matching local rule take
+ * that into account as well.
+ */
+ may = smk_access_entry(srp->smk_subject, osmack,
+ &tsp->smk_rules);
+ if (may == -ENOENT)
+ may = srp->smk_access;
+ else
+ may &= srp->smk_access;
+ /*
+ * If may is zero the SMACK64MMAP subject can't
+ * possibly have less access.
+ */
+ if (may == 0)
continue;
- rc = smk_mmap_list_check(msmack, srp->smk_object,
- srp->smk_access, &tsp->smk_rules);
- if (rc != 0)
+ /*
+ * Fetch the global list entry.
+ * If there isn't one a SMACK64MMAP subject
+ * can't have as much access as current.
+ */
+ mmay = smk_access_entry(msmack, osmack, &smack_rule_list);
+ if (mmay == -ENOENT) {
+ rc = -EACCES;
break;
+ }
+ /*
+ * If there is a local entry it modifies the
+ * potential access, too.
+ */
+ tmay = smk_access_entry(msmack, osmack, &tsp->smk_rules);
+ if (tmay != -ENOENT)
+ mmay &= tmay;
+
+ /*
+ * If there is any access available to current that is
+ * not available to a SMACK64MMAP subject
+ * deny access.
+ */
+ if ((may | mmay) != may) {
+ rc = -EACCES;
+ break;
+ }
}
rcu_read_unlock();