exec: introduce exec_binprm() for "depth == 0" code
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 <oleg@redhat.com> Acked-by: Kees Cook <keescook@chromium.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Evgeniy Polyakov <zbr@ioremap.net> Cc: Zach Levis <zml@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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5d1baf3b63
36
fs/exec.c
36
fs/exec.c
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@ -1373,7 +1373,6 @@ int search_binary_handler(struct linux_binprm *bprm)
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unsigned int depth = bprm->recursion_depth;
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int try,retval;
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struct linux_binfmt *fmt;
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pid_t old_pid, old_vpid;
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/* This allows 4 levels of binfmt rewrites before failing hard. */
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if (depth > 5)
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@ -1387,12 +1386,6 @@ int search_binary_handler(struct linux_binprm *bprm)
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if (retval)
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return retval;
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/* Need to fetch pid before load_binary changes it */
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old_pid = current->pid;
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rcu_read_lock();
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old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
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rcu_read_unlock();
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retval = -ENOENT;
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for (try=0; try<2; try++) {
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read_lock(&binfmt_lock);
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@ -1407,16 +1400,11 @@ int search_binary_handler(struct linux_binprm *bprm)
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retval = fn(bprm);
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bprm->recursion_depth = depth;
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if (retval >= 0) {
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if (depth == 0) {
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trace_sched_process_exec(current, old_pid, bprm);
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ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
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}
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put_binfmt(fmt);
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allow_write_access(bprm->file);
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if (bprm->file)
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fput(bprm->file);
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bprm->file = NULL;
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current->did_exec = 1;
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proc_exec_connector(current);
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return retval;
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}
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@ -1450,9 +1438,29 @@ int search_binary_handler(struct linux_binprm *bprm)
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}
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return retval;
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}
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EXPORT_SYMBOL(search_binary_handler);
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static int exec_binprm(struct linux_binprm *bprm)
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{
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pid_t old_pid, old_vpid;
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int ret;
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/* Need to fetch pid before load_binary changes it */
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old_pid = current->pid;
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rcu_read_lock();
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old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
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rcu_read_unlock();
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ret = search_binary_handler(bprm);
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if (ret >= 0) {
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trace_sched_process_exec(current, old_pid, bprm);
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ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
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current->did_exec = 1;
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}
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return ret;
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}
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/*
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* sys_execve() executes a new program.
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*/
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@ -1541,7 +1549,7 @@ static int do_execve_common(const char *filename,
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if (retval < 0)
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goto out;
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retval = search_binary_handler(bprm);
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retval = exec_binprm(bprm);
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if (retval < 0)
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goto out;
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