Commit b85e4676 added the nlm_privileged_requester() helper to check
whether an RPC request was sent from a local privileged caller. It
recognizes IPv4 privileged callers (from "127.0.0.1"), and IPv6
privileged callers (from "::1").
However, IPV6_ADDR_LOOPBACK is not set for the mapped IPv4 loopback
address (::ffff:7f00:0001), so the test breaks when the kernel's RPC
service is IPv6-enabled but user space is calling via the IPv4
loopback address. This is actually the most common case for IPv6-
enabled RPC services on Linux.
Rewrite the IPv6 check to handle the mapped IPv4 loopback address as
well as a normal IPv6 loopback address. For consistency, rewrite the
IPv4 check to match the same style as the IPv6 check, which is now
somewhat more broad than a strict check for 127.0.0.1.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/lockd/lockd.h | 17 +++++++++++++----
1 files changed, 13 insertions(+), 4 deletions(-)
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index b56d5aa..830148e 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -280,16 +280,25 @@ static inline struct inode *nlmsvc_file_inode(struct nlm_file *file)
static inline int __nlm_privileged_request4(const struct sockaddr *sap)
{
const struct sockaddr_in *sin = (struct sockaddr_in *)sap;
- return (sin->sin_addr.s_addr == htonl(INADDR_LOOPBACK)) &&
- (ntohs(sin->sin_port) < 1024);
+
+ if (ntohs(sin->sin_port) > 1023)
+ return 0;
+
+ return ipv4_is_loopback(sin->sin_addr.s_addr);
}
#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
static inline int __nlm_privileged_request6(const struct sockaddr *sap)
{
const struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)sap;
- return (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LOOPBACK) &&
- (ntohs(sin6->sin6_port) < 1024);
+
+ if (ntohs(sin6->sin6_port) > 1023)
+ return 0;
+
+ if (ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_MAPPED)
+ return ipv4_is_loopback(sin6->sin6_addr.s6_addr32[3]);
+
+ return ipv6_addr_type(&sin6->sin6_addr) & IPV6_ADDR_LOOPBACK;
}
#else /* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
static inline int __nlm_privileged_request6(const struct sockaddr *sap)
--
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