task_pid_nr_ns() and trace/ptrace code in the middle of the
recursive search_binary_handler() looks confusing and imho
annoying. We only need this code if "depth == 0", lets add
a simple helper which calls search_binary_handler() and does
trace_sched_process_exec() + ptrace_event().
The patch also moves the setting of task->did_exec, we need
to do this only once.
Note: we can kill either task->did_exec or PF_FORKNOEXEC.
Signed-off-by: Oleg Nesterov <o...@redhat.com>
Acked-by: Kees Cook <keesc...@chromium.org>
---
fs/exec.c | 36 ++++++++++++++++++++++--------------
1 files changed, 22 insertions(+), 14 deletions(-)
diff --git a/fs/exec.c b/fs/exec.c
index 9c73def..a9ae4f2 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1373,7 +1373,6 @@ int search_binary_handler(struct linux_binprm *bprm)
unsigned int depth = bprm->recursion_depth;
int try,retval;
struct linux_binfmt *fmt;
- pid_t old_pid, old_vpid;
/* This allows 4 levels of binfmt rewrites before failing hard. */
if (depth > 5)
@@ -1387,12 +1386,6 @@ int search_binary_handler(struct linux_binprm *bprm)
if (retval)
return retval;
- /* 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();
-
retval = -ENOENT;
for (try=0; try<2; try++) {
read_lock(&binfmt_lock);
@@ -1407,16 +1400,11 @@ int search_binary_handler(struct linux_binprm *bprm)
retval = fn(bprm);
bprm->recursion_depth = depth;
if (retval >= 0) {
- if (depth == 0) {
- trace_sched_process_exec(current,
old_pid, bprm);
- ptrace_event(PTRACE_EVENT_EXEC,
old_vpid);
- }
put_binfmt(fmt);
allow_write_access(bprm->file);
if (bprm->file)
fput(bprm->file);
bprm->file = NULL;
- current->did_exec = 1;
proc_exec_connector(current);
return retval;
}
@@ -1450,9 +1438,29 @@ int search_binary_handler(struct linux_binprm *bprm)
}
return retval;
}
-
EXPORT_SYMBOL(search_binary_handler);
+static int exec_binprm(struct linux_binprm *bprm)
+{
+ pid_t old_pid, old_vpid;
+ int ret;
+
+ /* 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();
+
+ ret = search_binary_handler(bprm);
+ if (ret >= 0) {
+ trace_sched_process_exec(current, old_pid, bprm);
+ ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
+ current->did_exec = 1;
+ }
+
+ return ret;
+}
+
/*
* sys_execve() executes a new program.
*/
@@ -1541,7 +1549,7 @@ static int do_execve_common(const char *filename,
if (retval < 0)
goto out;
- retval = search_binary_handler(bprm);
+ retval = exec_binprm(bprm);
if (retval < 0)
goto out;
--
1.5.5.1
--
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