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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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bdcf0a423e
In testing, we found that nfsd threads may call set_groups in parallel for the same entry cached in auth.unix.gid, racing in the call of groups_sort, corrupting the groups for that entry and leading to permission denials for the client. This patch: - Make groups_sort globally visible. - Move the call to groups_sort to the modifiers of group_info - Remove the call to groups_sort from set_groups Link: http://lkml.kernel.org/r/20171211151420.18655-1-thiago.becker@gmail.com Signed-off-by: Thiago Rafael Becker <thiago.becker@gmail.com> Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com> Reviewed-by: NeilBrown <neilb@suse.com> Acked-by: "J. Bruce Fields" <bfields@fieldses.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de> */
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#include <linux/sched.h>
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#include "nfsd.h"
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#include "auth.h"
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int nfsexp_flags(struct svc_rqst *rqstp, struct svc_export *exp)
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{
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struct exp_flavor_info *f;
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struct exp_flavor_info *end = exp->ex_flavors + exp->ex_nflavors;
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for (f = exp->ex_flavors; f < end; f++) {
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if (f->pseudoflavor == rqstp->rq_cred.cr_flavor)
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return f->flags;
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}
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return exp->ex_flags;
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}
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int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
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{
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struct group_info *rqgi;
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struct group_info *gi;
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struct cred *new;
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int i;
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int flags = nfsexp_flags(rqstp, exp);
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validate_process_creds();
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/* discard any old override before preparing the new set */
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revert_creds(get_cred(current_real_cred()));
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new = prepare_creds();
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if (!new)
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return -ENOMEM;
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new->fsuid = rqstp->rq_cred.cr_uid;
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new->fsgid = rqstp->rq_cred.cr_gid;
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rqgi = rqstp->rq_cred.cr_group_info;
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if (flags & NFSEXP_ALLSQUASH) {
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new->fsuid = exp->ex_anon_uid;
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new->fsgid = exp->ex_anon_gid;
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gi = groups_alloc(0);
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if (!gi)
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goto oom;
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} else if (flags & NFSEXP_ROOTSQUASH) {
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if (uid_eq(new->fsuid, GLOBAL_ROOT_UID))
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new->fsuid = exp->ex_anon_uid;
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if (gid_eq(new->fsgid, GLOBAL_ROOT_GID))
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new->fsgid = exp->ex_anon_gid;
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gi = groups_alloc(rqgi->ngroups);
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if (!gi)
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goto oom;
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for (i = 0; i < rqgi->ngroups; i++) {
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if (gid_eq(GLOBAL_ROOT_GID, rqgi->gid[i]))
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gi->gid[i] = exp->ex_anon_gid;
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else
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gi->gid[i] = rqgi->gid[i];
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/* Each thread allocates its own gi, no race */
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groups_sort(gi);
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}
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} else {
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gi = get_group_info(rqgi);
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}
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if (uid_eq(new->fsuid, INVALID_UID))
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new->fsuid = exp->ex_anon_uid;
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if (gid_eq(new->fsgid, INVALID_GID))
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new->fsgid = exp->ex_anon_gid;
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set_groups(new, gi);
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put_group_info(gi);
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if (!uid_eq(new->fsuid, GLOBAL_ROOT_UID))
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new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
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else
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new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
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new->cap_permitted);
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validate_process_creds();
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put_cred(override_creds(new));
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put_cred(new);
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validate_process_creds();
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return 0;
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oom:
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abort_creds(new);
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return -ENOMEM;
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}
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