selinux: introduce str_read() helper

There're some code duplication for reading a string value during
policydb_read().  Add str_read() helper to fix it.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Paul Moore <pmoore@redhat.com>

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 56eb65f67cb1ae4a2866217f1e00fb251ff2c716..bc2a586f095c5f73c214f1c475a2798a5f1439e3 100644 (file)
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -1080,6 +1080,26 @@ out:
  * binary representation file.
  */
 
+static int str_read(char **strp, gfp_t flags, void *fp, u32 len)
+{
+       int rc;
+       char *str;
+
+       str = kmalloc(len + 1, flags);
+       if (!str)
+               return -ENOMEM;
+
+       /* it's expected the caller should free the str */
+       *strp = str;
+
+       rc = next_entry(str, fp, len);
+       if (rc)
+               return rc;
+
+       str[len] = '\0';
+       return 0;
+}
+
 static int perm_read(struct policydb *p, struct hashtab *h, void *fp)
 {
        char *key = NULL;
@@ -1100,15 +1120,9 @@ static int perm_read(struct policydb *p, struct hashtab *h, void *fp)
        len = le32_to_cpu(buf[0]);
        perdatum->value = le32_to_cpu(buf[1]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = hashtab_insert(h, key, perdatum);
        if (rc)
@@ -1146,15 +1160,9 @@ static int common_read(struct policydb *p, struct hashtab *h, void *fp)
        comdatum->permissions.nprim = le32_to_cpu(buf[2]);
        nel = le32_to_cpu(buf[3]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        for (i = 0; i < nel; i++) {
                rc = perm_read(p, comdatum->permissions.table, fp);
@@ -1321,25 +1329,14 @@ static int class_read(struct policydb *p, struct hashtab *h, void *fp)
 
        ncons = le32_to_cpu(buf[5]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        if (len2) {
-               rc = -ENOMEM;
-               cladatum->comkey = kmalloc(len2 + 1, GFP_KERNEL);
-               if (!cladatum->comkey)
-                       goto bad;
-               rc = next_entry(cladatum->comkey, fp, len2);
+               rc = str_read(&cladatum->comkey, GFP_KERNEL, fp, len2);
                if (rc)
                        goto bad;
-               cladatum->comkey[len2] = '\0';
 
                rc = -EINVAL;
                cladatum->comdatum = hashtab_search(p->p_commons.table, cladatum->comkey);
@@ -1422,15 +1419,9 @@ static int role_read(struct policydb *p, struct hashtab *h, void *fp)
        if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
                role->bounds = le32_to_cpu(buf[2]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = ebitmap_read(&role->dominates, fp);
        if (rc)
@@ -1495,14 +1486,9 @@ static int type_read(struct policydb *p, struct hashtab *h, void *fp)
                typdatum->primary = le32_to_cpu(buf[2]);
        }
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = hashtab_insert(h, key, typdatum);
        if (rc)
@@ -1565,14 +1551,9 @@ static int user_read(struct policydb *p, struct hashtab *h, void *fp)
        if (p->policyvers >= POLICYDB_VERSION_BOUNDARY)
                usrdatum->bounds = le32_to_cpu(buf[2]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_KERNEL);
-       if (!key)
-               goto bad;
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_KERNEL, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = ebitmap_read(&usrdatum->roles, fp);
        if (rc)
@@ -1616,14 +1597,9 @@ static int sens_read(struct policydb *p, struct hashtab *h, void *fp)
        len = le32_to_cpu(buf[0]);
        levdatum->isalias = le32_to_cpu(buf[1]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_ATOMIC);
-       if (!key)
-               goto bad;
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_ATOMIC, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = -ENOMEM;
        levdatum->level = kmalloc(sizeof(struct mls_level), GFP_ATOMIC);
@@ -1664,14 +1640,9 @@ static int cat_read(struct policydb *p, struct hashtab *h, void *fp)
        catdatum->value = le32_to_cpu(buf[1]);
        catdatum->isalias = le32_to_cpu(buf[2]);
 
-       rc = -ENOMEM;
-       key = kmalloc(len + 1, GFP_ATOMIC);
-       if (!key)
-               goto bad;
-       rc = next_entry(key, fp, len);
+       rc = str_read(&key, GFP_ATOMIC, fp, len);
        if (rc)
                goto bad;
-       key[len] = '\0';
 
        rc = hashtab_insert(h, key, catdatum);
        if (rc)
@@ -1968,18 +1939,12 @@ static int filename_trans_read(struct policydb *p, void *fp)
                        goto out;
                len = le32_to_cpu(buf[0]);
 
-               rc = -ENOMEM;
-               name = kmalloc(len + 1, GFP_KERNEL);
-               if (!name)
-                       goto out;
-
-               ft->name = name;
-
                /* path component string */
-               rc = next_entry(name, fp, len);
+               rc = str_read(&name, GFP_KERNEL, fp, len);
                if (rc)
                        goto out;
-               name[len] = 0;
+
+               ft->name = name;
 
                rc = next_entry(buf, fp, sizeof(u32) * 4);
                if (rc)
@@ -2045,17 +2010,10 @@ static int genfs_read(struct policydb *p, void *fp)
                if (!newgenfs)
                        goto out;
 
-               rc = -ENOMEM;
-               newgenfs->fstype = kmalloc(len + 1, GFP_KERNEL);
-               if (!newgenfs->fstype)
-                       goto out;
-
-               rc = next_entry(newgenfs->fstype, fp, len);
+               rc = str_read(&newgenfs->fstype, GFP_KERNEL, fp, len);
                if (rc)
                        goto out;
 
-               newgenfs->fstype[len] = 0;
-
                for (genfs_p = NULL, genfs = p->genfs; genfs;
                     genfs_p = genfs, genfs = genfs->next) {
                        rc = -EINVAL;
@@ -2091,15 +2049,9 @@ static int genfs_read(struct policydb *p, void *fp)
                        if (!newc)
                                goto out;
 
-                       rc = -ENOMEM;
-                       newc->u.name = kmalloc(len + 1, GFP_KERNEL);
-                       if (!newc->u.name)
-                               goto out;
-
-                       rc = next_entry(newc->u.name, fp, len);
+                       rc = str_read(&newc->u.name, GFP_KERNEL, fp, len);
                        if (rc)
                                goto out;
-                       newc->u.name[len] = 0;
 
                        rc = next_entry(buf, fp, sizeof(u32));
                        if (rc)
@@ -2189,16 +2141,10 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
                                        goto out;
                                len = le32_to_cpu(buf[0]);
 
-                               rc = -ENOMEM;
-                               c->u.name = kmalloc(len + 1, GFP_KERNEL);
-                               if (!c->u.name)
-                                       goto out;
-
-                               rc = next_entry(c->u.name, fp, len);
+                               rc = str_read(&c->u.name, GFP_KERNEL, fp, len);
                                if (rc)
                                        goto out;
 
-                               c->u.name[len] = 0;
                                rc = context_read_and_validate(&c->context[0], p, fp);
                                if (rc)
                                        goto out;
@@ -2240,16 +2186,11 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
                                if (c->v.behavior > SECURITY_FS_USE_MAX)
                                        goto out;
 
-                               rc = -ENOMEM;
                                len = le32_to_cpu(buf[1]);
-                               c->u.name = kmalloc(len + 1, GFP_KERNEL);
-                               if (!c->u.name)
-                                       goto out;
-
-                               rc = next_entry(c->u.name, fp, len);
+                               rc = str_read(&c->u.name, GFP_KERNEL, fp, len);
                                if (rc)
                                        goto out;
-                               c->u.name[len] = 0;
+
                                rc = context_read_and_validate(&c->context[0], p, fp);
                                if (rc)
                                        goto out;