lkml.org 
[lkml]   [2021]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH RFC v2 2/4] process: add the PF_SUID flag
Date
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@redhat.com>
---
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
\
 
 \ /
  Last update: 2021-12-28 18:11    [W:0.089 / U:0.156 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site