Add two new options to the nfssvc(2) syscall that allow
processes running as root to suspend/resume execution of the kernel nfsd threads. An earlier version of this patch was tested by Vincent Hoffman (vince at unsane.co.uk) and John Hickey (jh at deterlab.net). Reviewed by: kib MFC after: 2 weeks
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parent
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6001db296e
Notes:
svn2git
2020-12-20 02:59:44 +00:00
svn path=/head/; revision=241561
@ -45,6 +45,8 @@ __FBSDID("$FreeBSD$");
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#include <security/mac/mac_framework.h>
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NFSDLOCKMUTEX;
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NFSV4ROOTLOCKMUTEX;
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struct nfsv4lock nfsd_suspend_lock;
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/*
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* Mapping of old NFS Version 2 RPC numbers to generic numbers.
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@ -221,9 +223,24 @@ nfssvc_program(struct svc_req *rqst, SVCXPRT *xprt)
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#ifdef MAC
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mac_cred_associate_nfsd(nd.nd_cred);
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#endif
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/*
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* Get a refcnt (shared lock) on nfsd_suspend_lock.
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* NFSSVC_SUSPENDNFSD will take an exclusive lock on
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* nfsd_suspend_lock to suspend these threads.
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* This must be done here, before the check of
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* nfsv4root exports by nfsvno_v4rootexport().
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*/
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NFSLOCKV4ROOTMUTEX();
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nfsv4_getref(&nfsd_suspend_lock, NULL, NFSV4ROOTLOCKMUTEXPTR,
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NULL);
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NFSUNLOCKV4ROOTMUTEX();
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if ((nd.nd_flag & ND_NFSV4) != 0) {
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nd.nd_repstat = nfsvno_v4rootexport(&nd);
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if (nd.nd_repstat != 0) {
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NFSLOCKV4ROOTMUTEX();
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nfsv4_relref(&nfsd_suspend_lock);
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NFSUNLOCKV4ROOTMUTEX();
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svcerr_weakauth(rqst);
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svc_freereq(rqst);
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m_freem(nd.nd_mrep);
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@ -233,6 +250,9 @@ nfssvc_program(struct svc_req *rqst, SVCXPRT *xprt)
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cacherep = nfs_proc(&nd, rqst->rq_xid, xprt->xp_socket,
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xprt->xp_sockref, &rp);
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NFSLOCKV4ROOTMUTEX();
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nfsv4_relref(&nfsd_suspend_lock);
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NFSUNLOCKV4ROOTMUTEX();
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} else {
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NFSMGET(nd.nd_mreq);
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nd.nd_mreq->m_len = 0;
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@ -57,6 +57,7 @@ extern struct mount nfsv4root_mnt;
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extern struct nfsrv_stablefirst nfsrv_stablefirst;
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extern void (*nfsd_call_servertimer)(void);
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extern SVCPOOL *nfsrvd_pool;
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extern struct nfsv4lock nfsd_suspend_lock;
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struct vfsoptlist nfsv4root_opt, nfsv4root_newopt;
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NFSDLOCKMUTEX;
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struct mtx nfs_cache_mutex;
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@ -3095,8 +3096,9 @@ nfssvc_srvcall(struct thread *p, struct nfssvc_args *uap, struct ucred *cred)
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struct nfsd_dumplocks *dumplocks;
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struct nameidata nd;
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vnode_t vp;
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int error = EINVAL;
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int error = EINVAL, igotlock;
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struct proc *procp;
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static int suspend_nfsd = 0;
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if (uap->flag & NFSSVC_PUBLICFH) {
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NFSBZERO((caddr_t)&nfs_pubfh.nfsrvfh_data,
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@ -3175,6 +3177,26 @@ nfssvc_srvcall(struct thread *p, struct nfssvc_args *uap, struct ucred *cred)
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nfsd_master_start = procp->p_stats->p_start;
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nfsd_master_proc = procp;
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PROC_UNLOCK(procp);
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} else if ((uap->flag & NFSSVC_SUSPENDNFSD) != 0) {
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NFSLOCKV4ROOTMUTEX();
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if (suspend_nfsd == 0) {
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/* Lock out all nfsd threads */
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do {
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igotlock = nfsv4_lock(&nfsd_suspend_lock, 1,
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NULL, NFSV4ROOTLOCKMUTEXPTR, NULL);
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} while (igotlock == 0 && suspend_nfsd == 0);
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suspend_nfsd = 1;
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}
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NFSUNLOCKV4ROOTMUTEX();
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error = 0;
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} else if ((uap->flag & NFSSVC_RESUMENFSD) != 0) {
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NFSLOCKV4ROOTMUTEX();
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if (suspend_nfsd != 0) {
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nfsv4_unlock(&nfsd_suspend_lock, 0);
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suspend_nfsd = 0;
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}
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NFSUNLOCKV4ROOTMUTEX();
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error = 0;
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}
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NFSEXITCODE(error);
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@ -102,7 +102,8 @@ sys_nfssvc(struct thread *td, struct nfssvc_args *uap)
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else if ((uap->flag & (NFSSVC_NFSDNFSD | NFSSVC_NFSDADDSOCK |
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NFSSVC_PUBLICFH | NFSSVC_V4ROOTEXPORT | NFSSVC_NOPUBLICFH |
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NFSSVC_STABLERESTART | NFSSVC_ADMINREVOKE |
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NFSSVC_DUMPCLIENTS | NFSSVC_DUMPLOCKS | NFSSVC_BACKUPSTABLE)) &&
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NFSSVC_DUMPCLIENTS | NFSSVC_DUMPLOCKS | NFSSVC_BACKUPSTABLE |
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NFSSVC_SUSPENDNFSD | NFSSVC_RESUMENFSD)) &&
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nfsd_call_nfsd != NULL)
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error = (*nfsd_call_nfsd)(td, uap);
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if (error == EINTR || error == ERESTART)
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@ -66,5 +66,7 @@
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#define NFSSVC_BACKUPSTABLE 0x00800000
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#define NFSSVC_ZEROCLTSTATS 0x01000000 /* modifier for GETSTATS */
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#define NFSSVC_ZEROSRVSTATS 0x02000000 /* modifier for GETSTATS */
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#define NFSSVC_SUSPENDNFSD 0x04000000
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#define NFSSVC_RESUMENFSD 0x08000000
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#endif /* _NFS_NFSSVC_H */
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