This is a note to let you know that I've just added the patch titled

    binder: use cred instead of task for getsecid

to the 5.10-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     binder-use-cred-instead-of-task-for-getsecid.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <sta...@vger.kernel.org> know about it.


>From foo@baz Sat Nov 13 12:23:35 PM CET 2021
From: Todd Kjos <tk...@google.com>
Date: Wed, 10 Nov 2021 15:00:36 -0800
Subject: binder: use cred instead of task for getsecid
To: sta...@vger.kernel.org, gre...@linuxfoundation.org, a...@android.com, 
tk...@android.com, m...@android.com, christ...@brauner.io, jmor...@namei.org, 
se...@hallyn.com, p...@paul-moore.com, stephen.smalley.w...@gmail.com, 
epa...@parisplace.org, keesc...@chromium.org, ja...@google.com, 
je...@google.com, zo...@linux.ibm.com, linux-security-mod...@vger.kernel.org, 
seli...@vger.kernel.org, de...@driverdev.osuosl.org
Cc: j...@joelfernandes.org, kernel-t...@android.com, Todd Kjos 
<tk...@google.com>, kernel test robot <l...@intel.com>, Casey Schaufler 
<ca...@schaufler-ca.com>
Message-ID: <20211110230036.3274365-3-tk...@google.com>

From: Todd Kjos <tk...@google.com>

commit 4d5b5539742d2554591751b4248b0204d20dcc9d upstream.

Use the 'struct cred' saved at binder_open() to lookup
the security ID via security_cred_getsecid(). This
ensures that the security context that opened binder
is the one used to generate the secctx.

Cc: sta...@vger.kernel.org # 5.4+
Fixes: ec74136ded79 ("binder: create node flag to request sender's security 
context")
Signed-off-by: Todd Kjos <tk...@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.w...@gmail.com>
Reported-by: kernel test robot <l...@intel.com>
Acked-by: Casey Schaufler <ca...@schaufler-ca.com>
Signed-off-by: Paul Moore <p...@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 drivers/android/binder.c |    2 +-
 include/linux/security.h |    5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -3102,7 +3102,7 @@ static void binder_transaction(struct bi
                u32 secid;
                size_t added_size;
 
-               security_task_getsecid(proc->tsk, &secid);
+               security_cred_getsecid(proc->cred, &secid);
                ret = security_secid_to_secctx(secid, &secctx, &secctx_sz);
                if (ret) {
                        return_error = BR_FAILED_REPLY;
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -1003,6 +1003,11 @@ static inline void security_transfer_cre
 {
 }
 
+static inline void security_cred_getsecid(const struct cred *c, u32 *secid)
+{
+       *secid = 0;
+}
+
 static inline int security_kernel_act_as(struct cred *cred, u32 secid)
 {
        return 0;


Patches currently in stable-queue which might be from tk...@google.com are

queue-5.10/binder-use-cred-instead-of-task-for-selinux-checks.patch
queue-5.10/binder-use-cred-instead-of-task-for-getsecid.patch
queue-5.10/binder-use-euid-from-cred-instead-of-using-task.patch
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