Fix a regression in NFSD's permission checking introduced by the credentials
patches. There are two parts to the problem, both in nfsd_setuser():
(1) The return value of set_groups() is -ve if in error, not 0, and should be
checked appropriately. 0 indicates success.
(2) The UID to use for fs accesses is in new->fsuid, not new->uid (which is
0). This causes CAP_DAC_OVERRIDE to always be set, rather than being
cleared if the UID is anything other than 0 after squashing.
Reported-by: J. Bruce Fields <bfields@xxxxxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
---
fs/nfsd/auth.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 0184fe9..c903e04 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -76,10 +76,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
ret = set_groups(new, gi);
put_group_info(gi);
- if (!ret)
+ if (ret < 0)
goto error;
- if (new->uid)
+ if (new->fsuid)
new->cap_effective = cap_drop_nfsd_set(new->cap_effective);
else
new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
--
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