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| author | Thiago Rafael Becker <thiago.becker@gmail.com> | 2017-12-14 15:33:12 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-01-10 09:29:52 +0100 |
| commit | 79258d9834803518a80b0ed0603c790638f0478b (patch) | |
| tree | e24060777442734ec52d5f8a44d1964fb5cbcaca /fs | |
| parent | 3a381abc5b703c0f10c2792e97ec805674e9197e (diff) | |
| download | linux-stable-79258d9834803518a80b0ed0603c790638f0478b.tar.gz linux-stable-79258d9834803518a80b0ed0603c790638f0478b.tar.bz2 linux-stable-79258d9834803518a80b0ed0603c790638f0478b.zip | |
kernel: make groups_sort calling a responsibility group_info allocators
commit bdcf0a423ea1c40bbb40e7ee483b50fc8aa3d758 upstream.
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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfsd/auth.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c index 62469c60be23..75f942ae5176 100644 --- a/fs/nfsd/auth.c +++ b/fs/nfsd/auth.c @@ -59,6 +59,9 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp) 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); |