From 11db2de0af2a919a11051f4c3050a63c3a003e46 Mon Sep 17 00:00:00 2001 From: Todd Kjos Date: Tue, 12 Oct 2021 09:56:14 -0700 Subject: [PATCH] BACKPORT: binder: use cred instead of task for getsecid 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 Suggested-by: Stephen Smalley Reported-by: kernel test robot Acked-by: Casey Schaufler Signed-off-by: Paul Moore Bug: 200688826 (cherry picked from commit 4d5b5539742d2554591751b4248b0204d20dcc9d) [ refactored to avoid changing KMI: struct binder_proc ] Change-Id: Ie023be3190caf20ca3901560455e9f027c9426cd --- drivers/android/binder.c | 2 +- include/linux/security.h | 5 +++++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 39778af28b25..962f3203aa6a 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -2865,7 +2865,7 @@ static void binder_transaction(struct binder_proc *proc, size_t added_size; int max_retries = 100; - security_task_getsecid(proc->tsk, &secid); + security_cred_getsecid(binder_get_cred(proc), &secid); retry_alloc: ret = security_secid_to_secctx(secid, &secctx, &secctx_sz); if (ret == -ENOMEM && max_retries-- > 0) { diff --git a/include/linux/security.h b/include/linux/security.h index 9af6bc48c751..a87cbacab078 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1011,6 +1011,11 @@ static inline void security_transfer_creds(struct cred *new, { } +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;