[linux-cifs-client] OOPS in request_key.c bisected (and then refound)

[Rutger Nijlunsing]

When trying to mount an CIFS share with SPGENO on Debian, I got
nothing. Digging deeping revealing on OOPS at function
call_sbin_request_key+0x166/0x255in 2.6.27 which was not there in
2.6.25. Bisecting this with the simplest command generating the OOPS,
which was taken from 'man keyctl':

    keyctl request2 user debug:yyyy spoon

took about 4 hours on the evolutionary dead-end Pentium 4 and returned
commit:

commit 69664cf16af4f31cd54d77948a4baf9c7e0ca7b9
Author: David Howells <dhowells at redhat.com>
Date:   Tue Apr 29 01:01:31 2008 -0700

    keys: don't generate user and user session keyrings unless they're accessed

...as the culprit.

Googling for this revealed that this OOPS had been reported before in
May, that a patch was written, tested and considered OK:
http://lists.samba.org/archive/linux-cifs-client/2008-May/003001.html

Applying this patch is still the right thing to do since it made the
OOPS disappear. Hopefully this will solve my SPNEGO problems, but
that's a second concern. Here is the patch again, together with
additional Tested-bys:

---
KEYS: Make request key instantiate the per-user keyrings

Make request_key() instantiate the per-user keyrings so that it doesn't oops
if it needs to get hold of the user session keyring because there isn't a
session keyring in place.

Signed-off-by: David Howells <dhowells at redhat.com>
Tested-by: Steve French <smfrench at gmail.com>
Tested-by: Rutger Nijlunsing <rutger.nijlunsing at gmail.com>
---

 security/keys/internal.h     |    1 +
 security/keys/process_keys.c |    2 +-
 security/keys/request_key.c  |    4 ++++
 3 files changed, 6 insertions(+), 1 deletions(-)


diff --git a/security/keys/internal.h b/security/keys/internal.h
index 8c05587..2bdfacc 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -108,6 +108,7 @@ extern key_ref_t search_process_keyrings(struct key_type *type,
 
 extern struct key *find_keyring_by_name(const char *name, bool skip_perm_check);
 
+extern int install_user_keyrings(struct task_struct *tsk);
 extern int install_thread_keyring(struct task_struct *tsk);
 extern int install_process_keyring(struct task_struct *tsk);
 
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index 5be6d01..45b240a 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -40,7 +40,7 @@ struct key_user root_key_user = {
 /*
  * install user and user session keyrings for a particular UID
  */
-static int install_user_keyrings(struct task_struct *tsk)
+int install_user_keyrings(struct task_struct *tsk)
 {
 	struct user_struct *user = tsk->user;
 	struct key *uid_keyring, *session_keyring;
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index ba32ca6..abea08f 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -74,6 +74,10 @@ static int call_sbin_request_key(struct key_construction *cons,
 
 	kenter("{%d},{%d},%s", key->serial, authkey->serial, op);
 
+	ret = install_user_keyrings(tsk);
+	if (ret < 0)
+		goto error_alloc;
+
 	/* allocate a new session keyring */
 	sprintf(desc, "_req.%u", key->serial);
 


-- 
Rutger Nijlunsing ---------------------------------- eludias ed dse.nl
never attribute to a conspiracy which can be explained by incompetence
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