sandbox: use sane access rights for files
When writing an executable, allowing other users to modify it introduces
a security issue.
Generally we should avoid giving other users write access to our files by
default.
Replace chmod(777) by chmod(755) and chmod(644).
Fixes: 47f5fcfb4169 ("sandbox: Add os_jump_to_image() to run another executable")
Fixes: d9165153caea ("sandbox: add flags for open() call")
Fixes: 5c2859cdc302 ("sandbox: Allow reading/writing of RAM buffer")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Sean Anderson <seanga2@gmail.com>
diff --git a/arch/sandbox/cpu/os.c b/arch/sandbox/cpu/os.c
index 154a5d7..d7869b2e 100644
--- a/arch/sandbox/cpu/os.c
+++ b/arch/sandbox/cpu/os.c
@@ -109,7 +109,7 @@
*/
flags |= O_CLOEXEC;
- return open(pathname, flags, 0777);
+ return open(pathname, flags, 0644);
}
int os_close(int fd)
@@ -746,7 +746,7 @@
struct sandbox_state *state = state_get_current();
int fd, ret;
- fd = open(fname, O_CREAT | O_WRONLY, 0777);
+ fd = open(fname, O_CREAT | O_WRONLY, 0644);
if (fd < 0)
return -ENOENT;
ret = write(fd, state->ram_buf, state->ram_size);
@@ -791,7 +791,7 @@
if (write(fd, data, size) < 0)
return -EIO;
close(fd);
- if (chmod(fname, 0777))
+ if (chmod(fname, 0755))
return -ENOEXEC;
return 0;