lkml.org 
[lkml]   [2021]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 5.15 10/26] binder: use cred instead of task for getsecid
Date
From: Todd Kjos <tkjos@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: stable@vger.kernel.org # 5.4+
Fixes: ec74136ded79 ("binder: create node flag to request sender's security context")
Signed-off-by: Todd Kjos <tkjos@google.com>
Suggested-by: Stephen Smalley <stephen.smalley.work@gmail.com>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Casey Schaufler <casey@schaufler-ca.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/android/binder.c | 11 +----------
include/linux/security.h | 5 +++++
2 files changed, 6 insertions(+), 10 deletions(-)

--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2722,16 +2722,7 @@ static void binder_transaction(struct bi
u32 secid;
size_t added_size;

- /*
- * Arguably this should be the task's subjective LSM secid but
- * we can't reliably access the subjective creds of a task
- * other than our own so we must use the objective creds, which
- * are safe to access. The downside is that if a task is
- * temporarily overriding it's creds it will not be reflected
- * here; however, it isn't clear that binder would handle that
- * case well anyway.
- */
- security_task_getsecid_obj(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
@@ -1041,6 +1041,11 @@ 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;

\
 
 \ /
  Last update: 2021-11-10 19:57    [W:0.114 / U:0.464 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site