diff options
| -rw-r--r-- | security/keys/request_key.c | 46 |
1 files changed, 37 insertions, 9 deletions
diff --git a/security/keys/request_key.c b/security/keys/request_key.c index c6880af8b411..114f7408feee 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -251,11 +251,12 @@ static int construct_key(struct key *key, const void *callout_info, * The keyring selected is returned with an extra reference upon it which the * caller must release. */ -static void construct_get_dest_keyring(struct key **_dest_keyring) +static int construct_get_dest_keyring(struct key **_dest_keyring) { struct request_key_auth *rka; const struct cred *cred = current_cred(); struct key *dest_keyring = *_dest_keyring, *authkey; + int ret; kenter("%p", dest_keyring); @@ -264,6 +265,8 @@ static void construct_get_dest_keyring(struct key **_dest_keyring) /* the caller supplied one */ key_get(dest_keyring); } else { + bool do_perm_check = true; + /* use a default keyring; falling through the cases until we * find one that we actually have */ switch (cred->jit_keyring) { @@ -278,8 +281,10 @@ static void construct_get_dest_keyring(struct key **_dest_keyring) dest_keyring = key_get(rka->dest_keyring); up_read(&authkey->sem); - if (dest_keyring) + if (dest_keyring) { + do_perm_check = false; break; + } } case KEY_REQKEY_DEFL_THREAD_KEYRING: @@ -314,11 +319,29 @@ static void construct_get_dest_keyring(struct key **_dest_keyring) default: BUG(); } + + /* + * Require Write permission on the keyring. This is essential + * because the default keyring may be the session keyring, and + * joining a keyring only requires Search permission. + * + * However, this check is skipped for the "requestor keyring" so + * that /sbin/request-key can itself use request_key() to add + * keys to the original requestor's destination keyring. + */ + if (dest_keyring && do_perm_check) { + ret = key_permission(make_key_ref(dest_keyring, 1), + KEY_NEED_WRITE); + if (ret) { + key_put(dest_keyring); + return ret; + } + } } *_dest_keyring = dest_keyring; kleave(" [dk %d]", key_serial(dest_keyring)); - return; + return 0; } /* @@ -444,11 +467,15 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx, if (ctx->index_key.type == &key_type_keyring) return ERR_PTR(-EPERM); - user = key_user_lookup(current_fsuid()); - if (!user) - return ERR_PTR(-ENOMEM); + ret = construct_get_dest_keyring(&dest_keyring); + if (ret) + goto error; - construct_get_dest_keyring(&dest_keyring); + user = key_user_lookup(current_fsuid()); + if (!user) { + ret = -ENOMEM; + goto error_put_dest_keyring; + } ret = construct_alloc_key(ctx, dest_keyring, flags, user, &key); key_user_put(user); @@ -463,7 +490,7 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx, } else if (ret == -EINPROGRESS) { ret = 0; } else { - goto couldnt_alloc_key; + goto error_put_dest_keyring; } key_put(dest_keyring); @@ -473,8 +500,9 @@ static struct key *construct_key_and_link(struct keyring_search_context *ctx, construction_failed: key_negate_and_link(key, key_negative_timeout, NULL, NULL); key_put(key); -couldnt_alloc_key: +error_put_dest_keyring: key_put(dest_keyring); +error: kleave(" = %d", ret); return ERR_PTR(ret); } |