Re: [PATCH 7/9] bsd-user: do_freebsd_sysctl helper for sysctl(2)

[Warner Losh <imp@bsdimp.com>]

[-- Attachment #1: Type: text/plain, Size: 1085 bytes --]

On Sat, Feb 11, 2023 at 4:09 PM Richard Henderson <
richard.henderson@linaro.org> wrote:

> On 2/10/23 13:18, Warner Losh wrote:
> > +abi_long do_freebsd_sysctl(CPUArchState *env, abi_ulong namep, int32_t
> namelen,
> > +        abi_ulong oldp, abi_ulong oldlenp, abi_ulong newp, abi_ulong
> newlen)
> > +{
> > +    abi_long ret;
> > +    void *hnamep, *holdp = NULL, *hnewp = NULL;
> > +    size_t holdlen;
> > +    abi_ulong oldlen = 0;
> > +    int32_t *snamep = g_malloc(sizeof(int32_t) * namelen), *p, *q, i;
> > +
> > +    if (oldlenp) {
> > +        if (get_user_ual(oldlen, oldlenp)) {
> > +            return -TARGET_EFAULT;
> > +        }
> > +    }
>
> You need to check for write early.  Either access_ok, or lock_user.
>
> > +    for (p = hnamep, q = snamep, i = 0; i < namelen; p++, i++) {
> > +        *q++ = tswap32(*p);
> > +    }
>
> Why the inconsistent increments?
>

no reason... Fixed.


> > +    unlock_user(holdp, oldp, holdlen);
>
> Usually we don't want writeback on error.
>

Indeed. Fixed as well.. in the other fixes for error handling.

Warner


>
> r~
>

[-- Attachment #2: Type: text/html, Size: 2012 bytes --]