linux-user: handle /proc/self/exe with execve() syscall

If path is /proc/self/exe, use the executable path
provided by exec_path.

Don't use execfd as it is closed by loader_exec() and otherwise
will survive to the exec() syscall and be usable child process.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220927124357.688536-2-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index ad06ec7..a7a2909 100644 (file)
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8860,7 +8860,11 @@ static abi_long do_syscall1(CPUArchState *cpu_env, int num, abi_long arg1,
              * before the execve completes and makes it the other
              * program's problem.
              */
-            ret = get_errno(safe_execve(p, argp, envp));
+            if (is_proc_myself(p, "exe")) {
+                ret = get_errno(safe_execve(exec_path, argp, envp));
+            } else {
+                ret = get_errno(safe_execve(p, argp, envp));
+            }
             unlock_user(p, arg1, 0);
 
             goto execve_end;