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ce52914eb7
A generic_cred can be used to look up a unx_cred or a gss_cred, so it's not really safe to use the the generic_cred->acred->ac_flags to store the NO_CRKEY_TIMEOUT flag. A lookup for a unx_cred triggered while the KEY_EXPIRE_SOON flag is already set will cause both NO_CRKEY_TIMEOUT and KEY_EXPIRE_SOON to be set in the ac_flags, leaving the user associated with the auth_cred to be in a state where they're perpetually doing 4K NFS_FILE_SYNC writes. This can be reproduced as follows: 1. Mount two NFS filesystems, one with sec=krb5 and one with sec=sys. They do not need to be the same export, nor do they even need to be from the same NFS server. Also, v3 is fine. $ sudo mount -o v3,sec=krb5 server1:/export /mnt/krb5 $ sudo mount -o v3,sec=sys server2:/export /mnt/sys 2. As the normal user, before accessing the kerberized mount, kinit with a short lifetime (but not so short that renewing the ticket would leave you within the 4-minute window again by the time the original ticket expires), e.g. $ kinit -l 10m -r 60m 3. Do some I/O to the kerberized mount and verify that the writes are wsize, UNSTABLE: $ dd if=/dev/zero of=/mnt/krb5/file bs=1M count=1 4. Wait until you're within 4 minutes of key expiry, then do some more I/O to the kerberized mount to ensure that RPC_CRED_KEY_EXPIRE_SOON gets set. Verify that the writes are 4K, FILE_SYNC: $ dd if=/dev/zero of=/mnt/krb5/file bs=1M count=1 5. Now do some I/O to the sec=sys mount. This will cause RPC_CRED_NO_CRKEY_TIMEOUT to be set: $ dd if=/dev/zero of=/mnt/sys/file bs=1M count=1 6. Writes for that user will now be permanently 4K, FILE_SYNC for that user, regardless of which mount is being written to, until you reboot the client. Renewing the kerberos ticket (assuming it hasn't already expired) will have no effect. Grabbing a new kerberos ticket at this point will have no effect either. Move the flag to the auth->au_flags field (which is currently unused) and rename it slightly to reflect that it's no longer associated with the auth_cred->ac_flags. Add the rpc_auth to the arg list of rpcauth_cred_key_to_expire and check the au_flags there too. Finally, add the inode to the arg list of nfs_ctx_key_to_expire so we can determine the rpc_auth to pass to rpcauth_cred_key_to_expire. Signed-off-by: Scott Mayhew <smayhew@redhat.com> Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
146 lines
2.7 KiB
C
146 lines
2.7 KiB
C
/*
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* linux/net/sunrpc/auth_null.c
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*
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* AUTH_NULL authentication. Really :-)
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*
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* Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
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*/
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#include <linux/types.h>
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#include <linux/module.h>
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#include <linux/sunrpc/clnt.h>
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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# define RPCDBG_FACILITY RPCDBG_AUTH
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#endif
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static struct rpc_auth null_auth;
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static struct rpc_cred null_cred;
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static struct rpc_auth *
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nul_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
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{
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atomic_inc(&null_auth.au_count);
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return &null_auth;
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}
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static void
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nul_destroy(struct rpc_auth *auth)
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{
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}
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/*
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* Lookup NULL creds for current process
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*/
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static struct rpc_cred *
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nul_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
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{
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if (flags & RPCAUTH_LOOKUP_RCU)
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return &null_cred;
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return get_rpccred(&null_cred);
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}
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/*
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* Destroy cred handle.
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*/
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static void
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nul_destroy_cred(struct rpc_cred *cred)
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{
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}
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/*
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* Match cred handle against current process
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*/
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static int
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nul_match(struct auth_cred *acred, struct rpc_cred *cred, int taskflags)
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{
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return 1;
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}
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/*
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* Marshal credential.
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*/
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static __be32 *
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nul_marshal(struct rpc_task *task, __be32 *p)
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{
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*p++ = htonl(RPC_AUTH_NULL);
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*p++ = 0;
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*p++ = htonl(RPC_AUTH_NULL);
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*p++ = 0;
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return p;
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}
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/*
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* Refresh credential. This is a no-op for AUTH_NULL
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*/
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static int
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nul_refresh(struct rpc_task *task)
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{
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set_bit(RPCAUTH_CRED_UPTODATE, &task->tk_rqstp->rq_cred->cr_flags);
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return 0;
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}
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static __be32 *
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nul_validate(struct rpc_task *task, __be32 *p)
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{
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rpc_authflavor_t flavor;
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u32 size;
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flavor = ntohl(*p++);
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if (flavor != RPC_AUTH_NULL) {
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printk("RPC: bad verf flavor: %u\n", flavor);
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return ERR_PTR(-EIO);
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}
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size = ntohl(*p++);
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if (size != 0) {
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printk("RPC: bad verf size: %u\n", size);
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return ERR_PTR(-EIO);
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}
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return p;
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}
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const struct rpc_authops authnull_ops = {
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.owner = THIS_MODULE,
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.au_flavor = RPC_AUTH_NULL,
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.au_name = "NULL",
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.create = nul_create,
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.destroy = nul_destroy,
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.lookup_cred = nul_lookup_cred,
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};
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static
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struct rpc_auth null_auth = {
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.au_cslack = NUL_CALLSLACK,
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.au_rslack = NUL_REPLYSLACK,
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.au_flags = RPCAUTH_AUTH_NO_CRKEY_TIMEOUT,
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.au_ops = &authnull_ops,
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.au_flavor = RPC_AUTH_NULL,
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.au_count = ATOMIC_INIT(0),
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};
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static
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const struct rpc_credops null_credops = {
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.cr_name = "AUTH_NULL",
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.crdestroy = nul_destroy_cred,
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.crbind = rpcauth_generic_bind_cred,
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.crmatch = nul_match,
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.crmarshal = nul_marshal,
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.crrefresh = nul_refresh,
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.crvalidate = nul_validate,
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};
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static
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struct rpc_cred null_cred = {
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.cr_lru = LIST_HEAD_INIT(null_cred.cr_lru),
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.cr_auth = &null_auth,
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.cr_ops = &null_credops,
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.cr_count = ATOMIC_INIT(1),
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.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE,
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#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
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.cr_magic = RPCAUTH_CRED_MAGIC,
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#endif
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};
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