selinux: make more use of str_read() when loading the policy

Simplify the call sites, and enable future string validation in a single
place.

Signed-off-by: Christian Göttsche <cgzones@googlemail.com>
[PM: subject tweak]
Signed-off-by: Paul Moore <paul@paul-moore.com>

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index d8dcaf2ca88f6322784a0ace8d62475622350ae3..1bebfcb9c6a12ad6c81861f3dda92a10ed07f1af 100644 (file)
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -230,17 +230,11 @@ int cond_read_bool(struct policydb *p, struct symtab *s, struct policy_file *fp)
                goto err;
 
        len = le32_to_cpu(buf[2]);
-       if (((len == 0) || (len == (u32)-1)))
-               goto err;
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto err;
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto err;
-       key[len] = '\0';
+
        rc = symtab_insert(s, key, booldatum);
        if (rc)
                goto err;

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 0850ea6ae018562e42516b3fc03a09aed9ed9d8f..9ea97194371363a5a4f6aa0e2dd035b28821c222 100644 (file)
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1093,7 +1093,7 @@ out:
  * binary representation file.
  */
 
-static int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len)
+int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len)
 {
        int rc;
        char *str;
@@ -2473,24 +2473,18 @@ int policydb_read(struct policydb *p, struct policy_file *fp)
                goto bad;
        }
 
-       rc = -ENOMEM;
-       policydb_str = kmalloc(len + 1, GFP_KERNEL);
-       if (!policydb_str) {
-               pr_err("SELinux:  unable to allocate memory for policydb "
-                      "string of length %d\n",
-                      len);
-               goto bad;
-       }
-
-       rc = next_entry(policydb_str, fp, len);
+       rc = str_read(&policydb_str, GFP_KERNEL, fp, len);
        if (rc) {
-               pr_err("SELinux:  truncated policydb string identifier\n");
-               kfree(policydb_str);
+               if (rc == -ENOMEM) {
+                       pr_err("SELinux:  unable to allocate memory for policydb string of length %d\n",
+                              len);
+               } else {
+                       pr_err("SELinux:  truncated policydb string identifier\n");
+               }
                goto bad;
        }
 
        rc = -EINVAL;
-       policydb_str[len] = '\0';
        if (strcmp(policydb_str, POLICYDB_STRING)) {
                pr_err("SELinux:  policydb string %s does not match "
                       "my string %s\n",

diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 80d1fa7e49954b3c848f30a9102e4f8607f733b9..25650224b6e7c8007832737965af4bec76276c7c 100644 (file)
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -386,6 +386,8 @@ static inline char *sym_name(struct policydb *p, unsigned int sym_num,
        return p->sym_val_to_name[sym_num][element_nr];
 }
 
+extern int str_read(char **strp, gfp_t flags, struct policy_file *fp, u32 len);
+
 extern u16 string_to_security_class(struct policydb *p, const char *name);
 extern u32 string_to_av_perm(struct policydb *p, u16 tclass, const char *name);