Problem: Old pid and vpid are redundantly saved aside before starting to
parse the binary, with the comment claiming that it is required since
load_binary changes it, though from inspection in the source,
load_binary does not change the pid and this wouldn't make sense since
execve does not create any new process, quote from man page of execve:
"there is no new process; many attributes of the calling process remain
unchanged (in particular, its PID)."
Solution: Remove the saving aside of both and later on use them directly
from the current object, instead of via the saved aside objects.
Signed-off-by: Nir Lichtman <nir@xxxxxxxxxxxx>
---
Side-note: Tested this solution with a defconfig x86_64 and an initramfs
with Busybox and confirmed to work fine.
fs/exec.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 506cd411f4ac..6bb0a7b15f7e 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1789,15 +1789,8 @@ static int search_binary_handler(struct linux_binprm *bprm)
/* binfmt handlers will call back into begin_new_exec() on success. */
static int exec_binprm(struct linux_binprm *bprm)
{
- pid_t old_pid, old_vpid;
int ret, depth;
- /* Need to fetch pid before load_binary changes it */
- old_pid = current->pid;
- rcu_read_lock();
- old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
- rcu_read_unlock();
-
/* This allows 4 levels of binfmt rewrites before failing hard. */
for (depth = 0;; depth++) {
struct file *exec;
@@ -1826,8 +1819,9 @@ static int exec_binprm(struct linux_binprm *bprm)
}
audit_bprm(bprm);
- trace_sched_process_exec(current, old_pid, bprm);
- ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
+ trace_sched_process_exec(current, current->pid, bprm);
+ ptrace_event(PTRACE_EVENT_EXEC,
+ task_pid_nr_ns(current, task_active_pid_ns(current->parent)));
proc_exec_connector(current);
return 0;
}
--
2.39.5
