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authorDavid Howells <dhowells@redhat.com>2009-09-02 09:13:40 +0100
committerJames Morris <jmorris@namei.org>2009-09-02 21:29:01 +1000
commite0e817392b9acf2c98d3be80c233dddb1b52003d (patch)
treeee680c020039313c9f9c40ab3542bb30a7363381 /fs/nfsd
parented6d76e4c32de0c2ad5f1d572b948ef49e465176 (diff)
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CRED: Add some configurable debugging [try #6]
Add a config option (CONFIG_DEBUG_CREDENTIALS) to turn on some debug checking for credential management. The additional code keeps track of the number of pointers from task_structs to any given cred struct, and checks to see that this number never exceeds the usage count of the cred struct (which includes all references, not just those from task_structs). Furthermore, if SELinux is enabled, the code also checks that the security pointer in the cred struct is never seen to be invalid. This attempts to catch the bug whereby inode_has_perm() faults in an nfsd kernel thread on seeing cred->security be a NULL pointer (it appears that the credential struct has been previously released): http://www.kerneloops.org/oops.php?number=252883 Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/auth.c4
-rw-r--r--fs/nfsd/nfssvc.c2
-rw-r--r--fs/nfsd/vfs.c3
3 files changed, 9 insertions, 0 deletions
diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 5573508f707..36fcabbf518 100644
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -34,6 +34,8 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
int flags = nfsexp_flags(rqstp, exp);
int ret;
+ validate_process_creds();
+
/* discard any old override before preparing the new set */
revert_creds(get_cred(current->real_cred));
new = prepare_creds();
@@ -86,8 +88,10 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
else
new->cap_effective = cap_raise_nfsd_set(new->cap_effective,
new->cap_permitted);
+ validate_process_creds();
put_cred(override_creds(new));
put_cred(new);
+ validate_process_creds();
return 0;
oom:
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 492c79b7800..24d58adfe5f 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -496,7 +496,9 @@ nfsd(void *vrqstp)
/* Lock the export hash tables for reading. */
exp_readlock();
+ validate_process_creds();
svc_process(rqstp);
+ validate_process_creds();
/* Unlock export hash tables */
exp_readunlock();
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 23341c1063b..8fa09bfbcba 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -684,6 +684,8 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
__be32 err;
int host_err;
+ validate_process_creds();
+
/*
* If we get here, then the client has already done an "open",
* and (hopefully) checked permission - so allow OWNER_OVERRIDE
@@ -740,6 +742,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type,
out_nfserr:
err = nfserrno(host_err);
out:
+ validate_process_creds();
return err;
}