hw/elf_ops: clear uninitialized segment space

When the mem_size of the segment is bigger than the file_size,
and if this space doesn't overlap another segment, it needs
to be cleared.

This bug is very similar to the one we had for linux-user,
22d113b52f41 ("linux-user: Fix loading of BSS segments"),
where .bss section is encoded as an extension of the the data
one by setting the segment p_memsz > p_filesz.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
[PMD: Use recently added address_space_set()]
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220115203725.3834712-3-laurent@vivier.eu>

1 files changed, 13 insertions, 0 deletions

diff --git a/include/hw/elf_ops.h b/include/hw/elf_ops.h
index 995de84..7c3b1d0 100644
--- a/include/hw/elf_ops.h
+++ b/include/hw/elf_ops.h
@@ -555,6 +555,19 @@ static ssize_t glue(load_elf, SZ)(const char *name, int fd,
                     if (res != MEMTX_OK) {
                         goto fail;
                     }
+                    /*
+                     * We need to zero'ify the space that is not copied
+                     * from file
+                     */
+                    if (file_size < mem_size) {
+                        res = address_space_set(as ? as : &address_space_memory,
+                                                addr + file_size, 0,
+                                                mem_size - file_size,
+                                                MEMTXATTRS_UNSPECIFIED);
+                        if (res != MEMTX_OK) {
+                            goto fail;
+                        }
+                    }
                 }
             }