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authorDavid Howells <dhowells@redhat.com>2011-08-22 14:08:33 +0100
committerJames Morris <jmorris@namei.org>2011-08-23 09:57:33 +1000
commit995995378f996a8aa1cf4e4ddc0f79fbfd45496f (patch)
treeddc0c1305767e683535120361a5f5848b7ae3803 /security/keys/process_keys.c
parentc5532b09bf40c398f2acfdd8f100c796d1d3f881 (diff)
KEYS: If install_session_keyring() is given a keyring, it should install it
If install_session_keyring() is given a keyring, it should install it rather than just creating a new one anyway. This was accidentally broken in: commit d84f4f992cbd76e8f39c488cf0c5d123843923b1 Author: David Howells <dhowells@redhat.com> Date: Fri Nov 14 10:39:23 2008 +1100 Subject: CRED: Inaugurate COW credentials The impact of that commit is that pam_keyinit no longer works correctly if 'force' isn't specified against a login process. This is because: keyctl_get_keyring_ID(KEY_SPEC_SESSION_KEYRING, 0) now always creates a new session keyring and thus the check whether the session keyring and the user-session keyring are the same is always false. This leads pam_keyinit to conclude that a session keyring is installed and it shouldn't be revoked by pam_keyinit here if 'revoke' is specified. Any system that specifies 'force' against pam_keyinit in the PAM configuration files for login methods (login, ssh, su -l, kdm, etc.) is not affected since that bypasses the broken check and forces the creation of a new session keyring anyway (for which the revoke flag is not cleared) - and any subsequent call to pam_keyinit really does have a session keyring already installed, and so the check works correctly there. Reverting to the previous behaviour will cause the kernel to subscribe the process to the user-session keyring as its session keyring if it doesn't have a session keyring of its own. pam_keyinit will detect this and install a new session keyring anyway (and won't clear the revert flag). This can be tested by commenting out pam_keyinit in the /etc/pam.d files and running the following program a couple of times in a row: #include <stdio.h> #include <stdlib.h> #include <keyutils.h> int main(int argc, char *argv[]) { key_serial_t uk, usk, sk; uk = keyctl_get_keyring_ID(KEY_SPEC_USER_KEYRING, 0); usk = keyctl_get_keyring_ID(KEY_SPEC_USER_SESSION_KEYRING, 0); sk = keyctl_get_keyring_ID(KEY_SPEC_SESSION_KEYRING, 0); printf("keys: %08x %08x %08x\n", uk, usk, sk); return 0; } Without the patch, I see: keys: 3884e281 24c4dfcf 22825f8e keys: 3884e281 24c4dfcf 068772be With the patch, I see: keys: 26be9c83 0e755ce0 0e755ce0 keys: 26be9c83 0e755ce0 0e755ce0 As can be seen, with the patch, the session keyring is the same as the user-session keyring each time; without the patch a new session keyring is generated each time. Reported-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Greg Wettstein <greg@enjellic.com> Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'security/keys/process_keys.c')
-rw-r--r--security/keys/process_keys.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c
index a3063eb3dc2..3bc6071ad63 100644
--- a/security/keys/process_keys.c
+++ b/security/keys/process_keys.c
@@ -270,7 +270,7 @@ static int install_session_keyring(struct key *keyring)
if (!new)
return -ENOMEM;
- ret = install_session_keyring_to_cred(new, NULL);
+ ret = install_session_keyring_to_cred(new, keyring);
if (ret < 0) {
abort_creds(new);
return ret;