TOMOYO: Add environment variable name restriction support.

[cascardo/linux.git] / security / tomoyo / domain.c

diff --git a/security/tomoyo/domain.c b/security/tomoyo/domain.c
index cd0f92d..5931fb1 100644 (file)
--- a/security/tomoyo/domain.c
+++ b/security/tomoyo/domain.c
@@ -562,6 +562,92 @@ out:
        return entry;
 }
 
+/**
+ * tomoyo_environ - Check permission for environment variable names.
+ *
+ * @ee: Pointer to "struct tomoyo_execve".
+ *
+ * Returns 0 on success, negative value otherwise.
+ */
+static int tomoyo_environ(struct tomoyo_execve *ee)
+{
+       struct tomoyo_request_info *r = &ee->r;
+       struct linux_binprm *bprm = ee->bprm;
+       /* env_page.data is allocated by tomoyo_dump_page(). */
+       struct tomoyo_page_dump env_page = { };
+       char *arg_ptr; /* Size is TOMOYO_EXEC_TMPSIZE bytes */
+       int arg_len = 0;
+       unsigned long pos = bprm->p;
+       int offset = pos % PAGE_SIZE;
+       int argv_count = bprm->argc;
+       int envp_count = bprm->envc;
+       int error = -ENOMEM;
+
+       ee->r.type = TOMOYO_MAC_ENVIRON;
+       ee->r.profile = r->domain->profile;
+       ee->r.mode = tomoyo_get_mode(r->domain->ns, ee->r.profile,
+                                    TOMOYO_MAC_ENVIRON);
+       if (!r->mode || !envp_count)
+               return 0;
+       arg_ptr = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
+       if (!arg_ptr)
+               goto out;
+       while (error == -ENOMEM) {
+               if (!tomoyo_dump_page(bprm, pos, &env_page))
+                       goto out;
+               pos += PAGE_SIZE - offset;
+               /* Read. */
+               while (argv_count && offset < PAGE_SIZE) {
+                       if (!env_page.data[offset++])
+                               argv_count--;
+               }
+               if (argv_count) {
+                       offset = 0;
+                       continue;
+               }
+               while (offset < PAGE_SIZE) {
+                       const unsigned char c = env_page.data[offset++];
+
+                       if (c && arg_len < TOMOYO_EXEC_TMPSIZE - 10) {
+                               if (c == '=') {
+                                       arg_ptr[arg_len++] = '\0';
+                               } else if (c == '\\') {
+                                       arg_ptr[arg_len++] = '\\';
+                                       arg_ptr[arg_len++] = '\\';
+                               } else if (c > ' ' && c < 127) {
+                                       arg_ptr[arg_len++] = c;
+                               } else {
+                                       arg_ptr[arg_len++] = '\\';
+                                       arg_ptr[arg_len++] = (c >> 6) + '0';
+                                       arg_ptr[arg_len++]
+                                               = ((c >> 3) & 7) + '0';
+                                       arg_ptr[arg_len++] = (c & 7) + '0';
+                               }
+                       } else {
+                               arg_ptr[arg_len] = '\0';
+                       }
+                       if (c)
+                               continue;
+                       if (tomoyo_env_perm(r, arg_ptr)) {
+                               error = -EPERM;
+                               break;
+                       }
+                       if (!--envp_count) {
+                               error = 0;
+                               break;
+                       }
+                       arg_len = 0;
+               }
+               offset = 0;
+       }
+out:
+       if (r->mode != TOMOYO_CONFIG_ENFORCING)
+               error = 0;
+       kfree(env_page.data);
+       kfree(arg_ptr);
+       return error;
+}
+
 /**
  * tomoyo_find_next_domain - Find a domain.
  *
@@ -581,6 +667,7 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
        bool reject_on_transition_failure = false;
        struct tomoyo_path_info rn = { }; /* real name */
        struct tomoyo_execve *ee = kzalloc(sizeof(*ee), GFP_NOFS);
+
        if (!ee)
                return -ENOMEM;
        ee->tmp = kzalloc(TOMOYO_EXEC_TMPSIZE, GFP_NOFS);
@@ -713,6 +800,10 @@ int tomoyo_find_next_domain(struct linux_binprm *bprm)
        bprm->cred->security = domain;
        if (need_kfree)
                kfree(rn.name);
+       if (!retval) {
+               ee->r.domain = domain;
+               retval = tomoyo_environ(ee);
+       }
        kfree(ee->tmp);
        kfree(ee->dump.data);
        kfree(ee);
@@ -732,7 +823,8 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
                      struct tomoyo_page_dump *dump)
 {
        struct page *page;
-       /* dump->data is released by tomoyo_finish_execve(). */
+
+       /* dump->data is released by tomoyo_find_next_domain(). */
        if (!dump->data) {
                dump->data = kzalloc(PAGE_SIZE, GFP_NOFS);
                if (!dump->data)
@@ -753,6 +845,7 @@ bool tomoyo_dump_page(struct linux_binprm *bprm, unsigned long pos,
                 * So do I.
                 */
                char *kaddr = kmap_atomic(page, KM_USER0);
+
                dump->page = page;
                memcpy(dump->data + offset, kaddr + offset,
                       PAGE_SIZE - offset);