On 3/26/24 12:20, Stefan O'Rear wrote:
> Commit 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
> introduced a RISC-V specific variant of the FLAT format which does not
> allocate any space for the (obsolescent) array of shared library
> pointers. However, it did not disable the code which initializes the
> array, resulting in the corruption of sizeof(long) bytes before the DATA
> segment, generally the end of the TEXT segment.
>
> Use CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET to guard initialization the
s/initialization the/the initialization of the
> shared library pointer region so that it will only be initialized if
> space is reserved for it.
>
> Fixes: 04d82a6d0881 ("binfmt_flat: allow not offsetting data start")
> Signed-off-by: Stefan O'Rear <sorear@xxxxxxxxxxxx>
> Tested-by: Waldemar Brodkorb <wbx@xxxxxxxxxxx>
It feels like CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET is not a very good name...
Maybe something like CONFIG_BINFMT_FLAT_NO_SHARED_LIBRARY would be better. But
renaming can be done in a followup patch.
Reviewed-by: Damien Le Moal <dlemoal
> ---
> fs/binfmt_flat.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
> index c26545d71d39..70c2b68988f4 100644
> --- a/fs/binfmt_flat.c
> +++ b/fs/binfmt_flat.c
> @@ -879,6 +879,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
> if (res < 0)
> return res;
>
> +#ifndef CONFIG_BINFMT_FLAT_NO_DATA_START_OFFSET
> /* Update data segment pointers for all libraries */
> for (i = 0; i < MAX_SHARED_LIBS; i++) {
> if (!libinfo.lib_list[i].loaded)
> @@ -893,6 +894,7 @@ static int load_flat_binary(struct linux_binprm *bprm)
> return -EFAULT;
> }
> }
> +#endif
>
> set_binfmt(&flat_format);
>
--
Damien Le Moal
Western Digital Research
