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authorKevin Coffman <kwc@citi.umich.edu>2008-04-29 01:01:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:16 -0700
commitdceba9944181b1fd5993417b5c8fa0e3dda38f8d (patch)
tree697e247a7a99c81af7ba4d7ad5d9cdf9941b3741
parent38bbca6b6f164e08a4a9cdfd719fff679af98375 (diff)
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keys: check starting keyring as part of search
Check the starting keyring as part of the search to (a) see if that is what we're searching for, and (b) to check it is still valid for searching. The scenario: User in process A does things that cause things to be created in its process session keyring. The user then does an su to another user and starts a new process, B. The two processes now share the same process session keyring. Process B does an NFS access which results in an upcall to gssd. When gssd attempts to instantiate the context key (to be linked into the process session keyring), it is denied access even though it has an authorization key. The order of calls is: keyctl_instantiate_key() lookup_user_key() (the default: case) search_process_keyrings(current) search_process_keyrings(rka->context) (recursive call) keyring_search_aux() keyring_search_aux() verifies the keys and keyrings underneath the top-level keyring it is given, but that top-level keyring is neither fully validated nor checked to see if it is the thing being searched for. This patch changes keyring_search_aux() to: 1) do more validation on the top keyring it is given and 2) check whether that top-level keyring is the thing being searched for Signed-off-by: Kevin Coffman <kwc@citi.umich.edu> Signed-off-by: David Howells <dhowells@redhat.com> Cc: Paul Moore <paul.moore@hp.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Stephen Smalley <sds@tycho.nsa.gov> Cc: James Morris <jmorris@namei.org> Cc: Kevin Coffman <kwc@citi.umich.edu> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: "J. Bruce Fields" <bfields@fieldses.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--security/keys/keyring.c35
1 files changed, 31 insertions, 4 deletions
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 88292e3dee9..70f0c313c88 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -292,7 +292,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
struct keyring_list *keylist;
struct timespec now;
- unsigned long possessed;
+ unsigned long possessed, kflags;
struct key *keyring, *key;
key_ref_t key_ref;
long err;
@@ -319,6 +319,32 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref,
err = -EAGAIN;
sp = 0;
+ /* firstly we should check to see if this top-level keyring is what we
+ * are looking for */
+ key_ref = ERR_PTR(-EAGAIN);
+ kflags = keyring->flags;
+ if (keyring->type == type && match(keyring, description)) {
+ key = keyring;
+
+ /* check it isn't negative and hasn't expired or been
+ * revoked */
+ if (kflags & (1 << KEY_FLAG_REVOKED))
+ goto error_2;
+ if (key->expiry && now.tv_sec >= key->expiry)
+ goto error_2;
+ key_ref = ERR_PTR(-ENOKEY);
+ if (kflags & (1 << KEY_FLAG_NEGATIVE))
+ goto error_2;
+ goto found;
+ }
+
+ /* otherwise, the top keyring must not be revoked, expired, or
+ * negatively instantiated if we are to search it */
+ key_ref = ERR_PTR(-EAGAIN);
+ if (kflags & ((1 << KEY_FLAG_REVOKED) | (1 << KEY_FLAG_NEGATIVE)) ||
+ (keyring->expiry && now.tv_sec >= keyring->expiry))
+ goto error_2;
+
/* start processing a new keyring */
descend:
if (test_bit(KEY_FLAG_REVOKED, &keyring->flags))
@@ -331,13 +357,14 @@ descend:
/* iterate through the keys in this keyring first */
for (kix = 0; kix < keylist->nkeys; kix++) {
key = keylist->keys[kix];
+ kflags = key->flags;
/* ignore keys not of this type */
if (key->type != type)
continue;
/* skip revoked keys and expired keys */
- if (test_bit(KEY_FLAG_REVOKED, &key->flags))
+ if (kflags & (1 << KEY_FLAG_REVOKED))
continue;
if (key->expiry && now.tv_sec >= key->expiry)
@@ -352,8 +379,8 @@ descend:
context, KEY_SEARCH) < 0)
continue;
- /* we set a different error code if we find a negative key */
- if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) {
+ /* we set a different error code if we pass a negative key */
+ if (kflags & (1 << KEY_FLAG_NEGATIVE)) {
err = -ENOKEY;
continue;
}