If the binary file in an execve system call is a suid executable, we add the PF_SUID flag to the process and all its future new children and threads. In a later commit, we will use this information to determine if it is safe to core dump such a process. Signed-off-by: Wander Lairson Costa <wander@xxxxxxxxxx> --- fs/exec.c | 4 ++++ include/linux/sched.h | 1 + kernel/fork.c | 2 ++ 3 files changed, 7 insertions(+) diff --git a/fs/exec.c b/fs/exec.c index ec07b36fdbb4..81d6ab9a4f64 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1309,6 +1309,10 @@ int begin_new_exec(struct linux_binprm * bprm) me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE | PF_NO_SETAFFINITY); + + if (bprm->suid_bin) + me->flags |= PF_SUID; + flush_thread(); me->personality &= ~bprm->per_clear; diff --git a/include/linux/sched.h b/include/linux/sched.h index 78c351e35fec..8ec2f907fb89 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1683,6 +1683,7 @@ extern struct pid *cad_pid; #define PF_KTHREAD 0x00200000 /* I am a kernel thread */ #define PF_RANDOMIZE 0x00400000 /* Randomize virtual address space */ #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */ +#define PF_SUID 0x01000000 /* The process comes from a suid/sgid binary */ #define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_mask */ #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */ #define PF_MEMALLOC_PIN 0x10000000 /* Allocation context constrained to zones which allow long term pinning. */ diff --git a/kernel/fork.c b/kernel/fork.c index 3244cc56b697..f0375d102b57 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -2076,6 +2076,8 @@ static __latent_entropy struct task_struct *copy_process( delayacct_tsk_init(p); /* Must remain after dup_task_struct() */ p->flags &= ~(PF_SUPERPRIV | PF_WQ_WORKER | PF_IDLE | PF_NO_SETAFFINITY); p->flags |= PF_FORKNOEXEC; + if (current->flags & PF_SUID) + p->flags |= PF_SUID; INIT_LIST_HEAD(&p->children); INIT_LIST_HEAD(&p->sibling); rcu_copy_process(p); -- 2.27.0
