From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- fs/nfsd/auth.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 108 insertions(+) create mode 100644 fs/nfsd/auth.c (limited to 'fs/nfsd/auth.c') diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c new file mode 100644 index 000000000..5ef9a0466 --- /dev/null +++ b/fs/nfsd/auth.c @@ -0,0 +1,108 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (C) 1995, 1996 Olaf Kirch */ + +#include +#include "nfsd.h" +#include "export.h" +#include "auth.h" + +int nfsexp_flags(struct svc_cred *cred, struct svc_export *exp) +{ + struct exp_flavor_info *f; + struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors; + + for (f = exp->ex_flavors; f < end; f++) { + if (f->pseudoflavor == cred->cr_flavor) + return f->flags; + } + return exp->ex_flags; + +} + +int nfsd_setuser(struct svc_cred *cred, struct svc_export *exp) +{ + struct group_info *rqgi; + struct group_info *gi; + struct cred *new; + int i; + int flags = nfsexp_flags(cred, exp); + + /* discard any old override before preparing the new set */ + put_cred(revert_creds(get_cred(current_real_cred()))); + new = prepare_creds(); + if (!new) + return -ENOMEM; + + new->fsuid = cred->cr_uid; + new->fsgid = cred->cr_gid; + + rqgi = cred->cr_group_info; + + if (flags & NFSEXP_ALLSQUASH) { + new->fsuid = exp->ex_anon_uid; + new->fsgid = exp->ex_anon_gid; + gi = groups_alloc(0); + if (!gi) + goto oom; + } else if (flags & NFSEXP_ROOTSQUASH) { + if (uid_eq(new->fsuid, GLOBAL_ROOT_UID)) + new->fsuid = exp->ex_anon_uid; + if (gid_eq(new->fsgid, GLOBAL_ROOT_GID)) + new->fsgid = exp->ex_anon_gid; + + gi = groups_alloc(rqgi->ngroups); + if (!gi) + goto oom; + + for (i = 0; i < rqgi->ngroups; i++) { + if (gid_eq(GLOBAL_ROOT_GID, rqgi->gid[i])) + gi->gid[i] = exp->ex_anon_gid; + else + gi->gid[i] = rqgi->gid[i]; + } + + /* Each thread allocates its own gi, no race */ + groups_sort(gi); + } else { + gi = get_group_info(rqgi); + } + + if (uid_eq(new->fsuid, INVALID_UID)) + new->fsuid = exp->ex_anon_uid; + if (gid_eq(new->fsgid, INVALID_GID)) + new->fsgid = exp->ex_anon_gid; + + set_groups(new, gi); + put_group_info(gi); + + if (!uid_eq(new->fsuid, GLOBAL_ROOT_UID)) + new->cap_effective = cap_drop_nfsd_set(new->cap_effective); + else + new->cap_effective = cap_raise_nfsd_set(new->cap_effective, + new->cap_permitted); + put_cred(override_creds(new)); + return 0; + +oom: + abort_creds(new); + return -ENOMEM; +} + +/** + * nfsd_user_namespace - Get user_namespace in effect for an RPC request + * @rqstp: RPC execution context + * + * xpt_cred is set once at transport creation and never modified. The + * transport itself is reference-counted during request processing, so + * no explicit reference on the namespace is necessary. + * + * Return: the user_namespace from the transport credential, or + * init_user_ns if no credential was set. The returned namespace pointer + * is valid for the duration of the RPC request. + */ +struct user_namespace *nfsd_user_namespace(const struct svc_rqst *rqstp) +{ + const struct cred *cred = rqstp->rq_xprt->xpt_cred; + + return cred ? cred->user_ns : &init_user_ns; +} -- cgit v1.3.1