write in 30M

hc

2024-02-20 ea08eeccae9297f7aabd2ef7f0c2517ac4549acc

 kernel/net/dns_resolver/dns_query.c
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@@ -1,7 +1,7 @@
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 /* Upcall routine, designed to work as a key type and working through
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  * /sbin/request-key to contact userspace when handling DNS queries.
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  *
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- * See Documentation/networking/dns_resolver.txt
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+ * See Documentation/networking/dns_resolver.rst
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  *
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  *   Copyright (c) 2007 Igor Mammedov
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  *   Author(s): Igor Mammedov (niallain@gmail.com)
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@@ -40,6 +40,7 @@
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 #include <linux/cred.h>
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 #include <linux/dns_resolver.h>
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 #include <linux/err.h>
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+#include <net/net_namespace.h>
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 #include <keys/dns_resolver-type.h>
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 #include <keys/user-type.h>
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@@ -48,12 +49,14 @@
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 /**
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  * dns_query - Query the DNS
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+ * @net: The network namespace to operate in.
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  * @type: Query type (or NULL for straight host->IP lookup)
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  * @name: Name to look up
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  * @namelen: Length of name
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  * @options: Request options (or NULL if no options)
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  * @_result: Where to place the returned data (or NULL)
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  * @_expiry: Where to store the result expiry time (or NULL)
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+ * @invalidate: Always invalidate the key after use
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  *
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  * The data will be returned in the pointer at *result, if provided, and the
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  * caller is responsible for freeing it.
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@@ -68,8 +71,10 @@
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  *
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  * Returns the size of the result on success, -ve error code otherwise.
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  */
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-int dns_query(const char *type, const char *name, size_t namelen,
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-	      const char *options, char **_result, time64_t *_expiry)
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+int dns_query(struct net *net,
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+	      const char *type, const char *name, size_t namelen,
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+	      const char *options, char **_result, time64_t *_expiry,
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+	      bool invalidate)
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 {
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 	struct key *rkey;
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 	struct user_key_payload *upayload;
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@@ -94,8 +99,6 @@
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 		desclen += typelen + 1;
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 	}
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-	if (!namelen)
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-		namelen = strnlen(name, 256);
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 	if (namelen < 3 || namelen > 255)
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 		return -EINVAL;
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 	desclen += namelen + 1;
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@@ -122,7 +125,7 @@
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 	 * add_key() to preinstall malicious redirections
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 	 */
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 	saved_cred = override_creds(dns_resolver_cache);
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-	rkey = request_key(&key_type_dns_resolver, desc, options);
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+	rkey = request_key_net(&key_type_dns_resolver, desc, net, options);
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 	revert_creds(saved_cred);
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 	kfree(desc);
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 	if (IS_ERR(rkey)) {
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@@ -148,12 +151,9 @@
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 	if (_result) {
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 		ret = -ENOMEM;
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-		*_result = kmalloc(len + 1, GFP_KERNEL);
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+		*_result = kmemdup_nul(upayload->data, len, GFP_KERNEL);
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 		if (!*_result)
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 			goto put;
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-
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-		memcpy(*_result, upayload->data, len);
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-		(*_result)[len] = '\0';
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 	}
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 	if (_expiry)
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@@ -162,6 +162,8 @@
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 	ret = len;
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 put:
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 	up_read(&rkey->sem);
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+	if (invalidate)
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+		key_invalidate(rkey);
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 	key_put(rkey);
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 out:
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 	kleave(" = %d", ret);