47 lines
1.6 KiB
Diff
47 lines
1.6 KiB
Diff
From: Ben Hutchings <ben.hutchings@codethink.co.uk>
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Date: Mon, 22 Jan 2018 20:11:06 +0000
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Subject: nfsd: auth: Fix gid sorting when rootsquash enabled
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Origin: https://git.kernel.org/linus/1995266727fa8143897e89b55f5d3c79aa828420
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Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2018-1000028
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Commit bdcf0a423ea1 ("kernel: make groups_sort calling a responsibility
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group_info allocators") appears to break nfsd rootsquash in a pretty
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major way.
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It adds a call to groups_sort() inside the loop that copies/squashes
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gids, which means the valid gids are sorted along with the following
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garbage. The net result is that the highest numbered valid gids are
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replaced with any lower-valued garbage gids, possibly including 0.
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We should sort only once, after filling in all the gids.
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Fixes: bdcf0a423ea1 ("kernel: make groups_sort calling a responsibility ...")
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Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
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Acked-by: J. Bruce Fields <bfields@redhat.com>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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fs/nfsd/auth.c | 6 +++---
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1 file changed, 3 insertions(+), 3 deletions(-)
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diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
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index f650e475d8f0..fdf2aad73470 100644
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--- a/fs/nfsd/auth.c
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+++ b/fs/nfsd/auth.c
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@@ -60,10 +60,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
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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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-
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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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+
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+ /* Each thread allocates its own gi, no race */
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+ groups_sort(gi);
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} else {
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gi = get_group_info(rqgi);
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}
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--
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2.11.0
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