linux-user: don't use AT_EXECFD in do_openat()

AT_EXECFD gives access to the binary file even if
it is not readable (only executable).

Moreover it can be opened with flags and mode that are not the ones
provided by do_openat() caller.

And it is not available because loader_exec() has closed it.

To avoid that, use only safe_openat() with the exec_path.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20220927124357.688536-3-laurent@vivier.eu>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index a7a2909..665db67 100644 (file)
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -8251,8 +8251,7 @@ static int do_openat(CPUArchState *cpu_env, int dirfd, const char *pathname, int
     };
 
     if (is_proc_myself(pathname, "exe")) {
-        int execfd = qemu_getauxval(AT_EXECFD);
-        return execfd ? execfd : safe_openat(dirfd, exec_path, flags, mode);
+        return safe_openat(dirfd, exec_path, flags, mode);
     }
 
     for (fake_open = fakes; fake_open->filename; fake_open++) {