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nfsd: widen nfsd_genl_rqstp address fields to sockaddr_storage

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struct nfsd_genl_rqstp declares rq_daddr and rq_saddr as plain
"struct sockaddr" (16 bytes). When an IPv6 NFS client is connected,
nfsd_genl_rpc_status_compose_msg() casts these fields to
"struct sockaddr_in6 *" (28 bytes) and reads sin6_addr at offset 8..24,
which extends 8 bytes past the end of the 16-byte sockaddr field into
the adjacent rq_flags member. The 16-byte nla_put_in6_addr then ships 8
bytes of truncated IPv6 address followed by 8 bytes of rq_flags to
userspace via the NFSD_A_RPC_STATUS_SADDR6/DADDR6 netlink attributes.

This is reachable by any unprivileged process in the network namespace
because NFSD_CMD_RPC_STATUS_GET uses GENL_CMD_CAP_DUMP without
GENL_ADMIN_PERM.

Fix by widening rq_daddr and rq_saddr to struct sockaddr_storage so the
IPv6 casts operate within bounds, copying sizeof(struct sockaddr_storage)
bytes in the memcpy calls so the full address is captured, and
zero-initializing the genl_rqstp stack variable to prevent leaking
uninitialized tail bytes through netlink.

Fixes: bd9d6a3efa ("NFSD: add rpc_status netlink support")
Cc: stable@vger.kernel.org
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260602-nfsd-testing-v2-5-e4ea62e3cd5c@kernel.org
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Jeff Layton
2026-06-02 12:23:17 -04:00
committed by Chuck Lever
parent 9f1ddfc8cb
commit a99d720ed2
1 changed files with 6 additions and 6 deletions
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12
fs/nfsd/nfsctl.c
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@@ -1414,8 +1414,8 @@ static int create_proc_exports_entry(void)
unsigned int nfsd_net_id;
struct nfsd_genl_rqstp {
struct sockaddr rq_daddr;
struct sockaddr rq_saddr;
struct sockaddr_storage rq_daddr;
struct sockaddr_storage rq_saddr;
unsigned long rq_flags;
ktime_t rq_stime;
__be32 rq_xid;
@@ -1450,7 +1450,7 @@ static int nfsd_genl_rpc_status_compose_msg(struct sk_buff *skb,
NFSD_A_RPC_STATUS_PAD))
return -ENOBUFS;
switch (genl_rqstp->rq_saddr.sa_family) {
switch (genl_rqstp->rq_saddr.ss_family) {
case AF_INET: {
const struct sockaddr_in *s_in, *d_in;
@@ -1527,7 +1527,7 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
list_for_each_entry_rcu(rqstp,
&nn->nfsd_serv->sv_pools[i].sp_all_threads,
rq_all) {
struct nfsd_genl_rqstp genl_rqstp;
struct nfsd_genl_rqstp genl_rqstp = {};
unsigned int status_counter;
if (rqstp_index++ < cb->args[1]) /* already consumed */
@@ -1551,9 +1551,9 @@ int nfsd_nl_rpc_status_get_dumpit(struct sk_buff *skb,
genl_rqstp.rq_stime = rqstp->rq_stime;
genl_rqstp.rq_opcnt = 0;
memcpy(&genl_rqstp.rq_daddr, svc_daddr(rqstp),
sizeof(struct sockaddr));
sizeof(struct sockaddr_storage));
memcpy(&genl_rqstp.rq_saddr, svc_addr(rqstp),
sizeof(struct sockaddr));
sizeof(struct sockaddr_storage));
#ifdef CONFIG_NFSD_V4
if (rqstp->rq_vers == NFS4_VERSION &&