58 lines
1.8 KiB
Diff
58 lines
1.8 KiB
Diff
|
From: David Howells <dhowells@redhat.com>
|
||
|
|
Subject: [PATCH] KEYS: Fix bug in keyctl_session_to_parent() if parent has no session keyring
|
||
|
|
|
||
|
|
Fix a bug in keyctl_session_to_parent() whereby it tries to check the ownership
|
||
|
|
of the parent process's session keyring whether or not the parent has a session
|
||
|
|
keyring [CVE-2010-2960].
|
||
|
|
|
||
|
|
A program like the following:
|
||
|
|
|
||
|
|
#include <unistd.h>
|
||
|
|
#include <keyutils.h>
|
||
|
|
int main(int argc, char **argv)
|
||
|
|
{
|
||
|
|
keyctl(KEYCTL_SESSION_TO_PARENT);
|
||
|
|
}
|
||
|
|
|
||
|
|
can be used to trigger the following bug report:
|
||
|
|
|
||
|
|
BUG: unable to handle kernel NULL pointer dereference at 00000000000000a0
|
||
|
|
IP: [<ffffffff811ae4dd>] keyctl_session_to_parent+0x251/0x443
|
||
|
|
...
|
||
|
|
Call Trace:
|
||
|
|
[<ffffffff811ae2f3>] ? keyctl_session_to_parent+0x67/0x443
|
||
|
|
[<ffffffff8109d286>] ? __do_fault+0x24b/0x3d0
|
||
|
|
[<ffffffff811af98c>] sys_keyctl+0xb4/0xb8
|
||
|
|
[<ffffffff81001eab>] system_call_fastpath+0x16/0x1b
|
||
|
|
|
||
|
|
if there is no parent process.
|
||
|
|
|
||
|
|
If the system is using pam_keyinit then it mostly protected against this as all
|
||
|
|
processes derived from a login will have inherited the session keyring created
|
||
|
|
by pam_keyinit during the log in procedure.
|
||
|
|
|
||
|
|
To test this, pam_keyinit calls need to be commented out in /etc/pam.d/.
|
||
|
|
|
||
|
|
Signed-off-by: David Howells <dhowells@redhat.com>
|
||
|
|
---
|
||
|
|
|
||
|
|
security/keys/keyctl.c | 3 ++-
|
||
|
|
1 files changed, 2 insertions(+), 1 deletions(-)
|
||
|
|
|
||
|
|
|
||
|
|
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
|
||
|
|
index 3868c67..60924f6 100644
|
||
|
|
--- a/security/keys/keyctl.c
|
||
|
|
+++ b/security/keys/keyctl.c
|
||
|
|
@@ -1305,7 +1305,8 @@ long keyctl_session_to_parent(void)
|
||
|
|
goto not_permitted;
|
||
|
|
|
||
|
|
/* the keyrings must have the same UID */
|
||
|
|
- if (pcred ->tgcred->session_keyring->uid != mycred->euid ||
|
||
|
|
+ if ((pcred->tgcred->session_keyring &&
|
||
|
|
+ pcred->tgcred->session_keyring->uid != mycred->euid) ||
|
||
|
|
mycred->tgcred->session_keyring->uid != mycred->euid)
|
||
|
|
goto not_permitted;
|
||
|
|
|
||
|
|
|