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 5.4-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-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From foo@baz Sat Nov 13 12:18:28 PM CET 2021
From: Todd Kjos <[email protected]>
Date: Wed, 10 Nov 2021 15:00:25 -0800
Subject: binder: use cred instead of task for getsecid
To: [email protected], [email protected], [email protected], 
[email protected], [email protected], [email protected], [email protected], 
[email protected], [email protected], [email protected], 
[email protected], [email protected], [email protected], 
[email protected], [email protected], [email protected], 
[email protected], [email protected]
Cc: [email protected], [email protected], Todd Kjos 
<[email protected]>, kernel test robot <[email protected]>, Casey Schaufler 
<[email protected]>
Message-ID: <[email protected]>

From: Todd Kjos <[email protected]>

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: [email protected] # 5.4+
Fixes: ec74136ded79 ("binder: create node flag to request sender's security 
context")
Signed-off-by: Todd Kjos <[email protected]>
Suggested-by: Stephen Smalley <[email protected]>
Reported-by: kernel test robot <[email protected]>
Acked-by: Casey Schaufler <[email protected]>
Signed-off-by: Paul Moore <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 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
@@ -3106,7 +3106,7 @@ 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
@@ -985,6 +985,11 @@ 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 [email protected] are

queue-5.4/binder-use-cred-instead-of-task-for-selinux-checks.patch
queue-5.4/binder-use-cred-instead-of-task-for-getsecid.patch
queue-5.4/binder-use-euid-from-cred-instead-of-using-task.patch
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