Re: [PATCH] lib: sbi_domain: reject zero-size and overflowing ranges in sbi_domain_check_addr_range

On Wed, Apr 22, 2026 at 8:48 PM liutong <[email protected]> wrote:
>
> `max = addr + size` is computed without overflow detection, and a
> size of zero is not rejected. In both cases the `while (addr < max)`
> loop executes zero times and the function falls through to
> `return true` without actually checking any region against the
> domain configuration.
>
> Reject size == 0 and detect unsigned overflow of addr + size before
> entering the loop.
>
> Fixes: eab48c33a12d ("lib: sbi: Add sbi_domain_check_addr_range() function")
> Signed-off-by: liutong <[email protected]>

The problem of overflowing ranges is already taken care by
the patch "lib: sbi_domain: reject overflowing address range
in check_addr_range()" so you might want to focus only on
"reject zero-size".

Regards,
Anup

> ---
> Apologies for the earlier non-standard submission; resending as a
> proper patch per docs/contributing.md.
>
>  lib/sbi/sbi_domain.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/lib/sbi/sbi_domain.c b/lib/sbi/sbi_domain.c
> index 7030848d..74a02057 100644
> --- a/lib/sbi/sbi_domain.c
> +++ b/lib/sbi/sbi_domain.c
> @@ -499,12 +499,17 @@ bool sbi_domain_check_addr_range(const struct sbi_domain *dom,
>                                  unsigned long mode,
>                                  unsigned long access_flags)
>  {
> -       unsigned long max = addr + size;
> +       unsigned long max;
>         const struct sbi_domain_memregion *reg, *sreg;
>
>         if (!dom)
>                 return false;
>
> +       if (!size || (addr + size) < addr)
> +               return false;
> +
> +       max = addr + size;
> +
>         while (addr < max) {
>                 reg = find_region(dom, addr);
>                 if (!reg)
> --
> 2.34.1
>
>
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