Re: [PATCH v4] linux-user: Add most IFTUN ioctls

[Laurent Vivier]

Le 29/09/2020 à 03:48, Shu-Chun Weng via a écrit :
> The three options handling `struct sock_fprog` (TUNATTACHFILTER,
> TUNDETACHFILTER, and TUNGETFILTER) are not implemented. Linux kernel
> keeps a user space pointer in them which we cannot correctly handle.
> 
> Signed-off-by: Josh Kunz <jkz@google.com>
> Signed-off-by: Shu-Chun Weng <scw@google.com>
> ---
> v2->v3:
>   IOCTL_SPECIAL(TUNSETTXFILTER) type changed to MK_PTR(TYPE_PTRVOID) for 
> strace
>   to display the raw pointer.
> 
>   Updated do_ioctl_TUNSETTXFILTER for correct usages of unlock_user() and
>   offsetof().
> 
> v3->v4:
>   IOCTL_SPECIAL(TUNSETTXFILTER) corrected to TYPE_PTRVOID.
> 
>  linux-user/ioctls.h       | 46 +++++++++++++++++++++++++++++++++++++++
>  linux-user/syscall.c      | 38 ++++++++++++++++++++++++++++++++
>  linux-user/syscall_defs.h | 32 +++++++++++++++++++++++++++
>  3 files changed, 116 insertions(+)
> 
> diff --git a/linux-user/ioctls.h b/linux-user/ioctls.h
> index 0713ae1311..c6e5926eb4 100644
> --- a/linux-user/ioctls.h
> +++ b/linux-user/ioctls.h
> @@ -593,3 +593,49 @@
>    IOCTL(KCOV_DISABLE, 0, TYPE_NULL)
>    IOCTL(KCOV_INIT_TRACE, IOC_R, TYPE_ULONG)
>  #endif
> +
> +  IOCTL(TUNSETDEBUG,     IOC_W, TYPE_INT)
> +  IOCTL(TUNSETIFF,       IOC_RW, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
> +  IOCTL(TUNSETPERSIST,   IOC_W, TYPE_INT)
> +  IOCTL(TUNSETOWNER,     IOC_W, TYPE_INT)
> +  IOCTL(TUNSETLINK,      IOC_W, TYPE_INT)
> +  IOCTL(TUNSETGROUP,     IOC_W, TYPE_INT)
> +  IOCTL(TUNGETFEATURES,  IOC_R, MK_PTR(TYPE_INT))
> +  IOCTL(TUNSETOFFLOAD,   IOC_W, TYPE_LONG)
> +  IOCTL_SPECIAL(TUNSETTXFILTER, IOC_W, do_ioctl_TUNSETTXFILTER,
> +                /*
> +                 * We can't represent `struct tun_filter` in thunk so leaving
> +                 * it uninterpreted. do_ioctl_TUNSETTXFILTER will do the
> +                 * conversion.
> +                 */
> +                TYPE_PTRVOID)
> +  IOCTL(TUNGETIFF,       IOC_R, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
> +  IOCTL(TUNGETSNDBUF,    IOC_R, MK_PTR(TYPE_INT))
> +  IOCTL(TUNSETSNDBUF,    IOC_W, MK_PTR(TYPE_INT))
> +  /*
> +   * TUNATTACHFILTER and TUNDETACHFILTER are not supported. Linux kernel 
> keeps a
> +   * user pointer in TUNATTACHFILTER, which we are not able to correctly 
> handle.
> +   */
> +  IOCTL(TUNGETVNETHDRSZ, IOC_R, MK_PTR(TYPE_INT))
> +  IOCTL(TUNSETVNETHDRSZ, IOC_W, MK_PTR(TYPE_INT))
> +  IOCTL(TUNSETQUEUE,     IOC_W, MK_PTR(MK_STRUCT(STRUCT_short_ifreq)))
> +  IOCTL(TUNSETIFINDEX ,  IOC_W, MK_PTR(TYPE_INT))
> +  /* TUNGETFILTER is not supported: see TUNATTACHFILTER. */
> +  IOCTL(TUNSETVNETLE,    IOC_W, MK_PTR(TYPE_INT))
> +  IOCTL(TUNGETVNETLE,    IOC_R, MK_PTR(TYPE_INT))
> +#ifdef TUNSETVNETBE
> +  IOCTL(TUNSETVNETBE,    IOC_W, MK_PTR(TYPE_INT))
> +  IOCTL(TUNGETVNETBE,    IOC_R, MK_PTR(TYPE_INT))
> +#endif
> +#ifdef TUNSETSTEERINGEBPF
> +  IOCTL(TUNSETSTEERINGEBPF, IOC_W, MK_PTR(TYPE_INT))
> +#endif
> +#ifdef TUNSETFILTEREBPF
> +  IOCTL(TUNSETFILTEREBPF, IOC_W, MK_PTR(TYPE_INT))
> +#endif
> +#ifdef TUNSETCARRIER
> +  IOCTL(TUNSETCARRIER,   IOC_W, MK_PTR(TYPE_INT))
> +#endif
> +#ifdef TUNGETDEVNETNS
> +  IOCTL(TUNGETDEVNETNS,  IOC_R, TYPE_NULL)
> +#endif
> diff --git a/linux-user/syscall.c b/linux-user/syscall.c
> index 945fc25279..1c955bc675 100644
> --- a/linux-user/syscall.c
> +++ b/linux-user/syscall.c
> @@ -56,6 +56,7 @@
>  #include <linux/wireless.h>
>  #include <linux/icmp.h>
>  #include <linux/icmpv6.h>
> +#include <linux/if_tun.h>
>  #include <linux/errqueue.h>
>  #include <linux/random.h>
>  #ifdef CONFIG_TIMERFD
> @@ -5415,6 +5416,43 @@ static abi_long do_ioctl_drm(const IOCTLEntry *ie, 
> uint8_t *buf_temp,
>  
>  #endif
>  
> +static abi_long do_ioctl_TUNSETTXFILTER(const IOCTLEntry *ie, uint8_t 
> *buf_temp,
> +                                        int fd, int cmd, abi_long arg)
> +{
> +    struct tun_filter *filter = (struct tun_filter *)buf_temp;
> +    struct tun_filter *target_filter;
> +    char *target_addr;
> +
> +    assert(ie->access == IOC_W);
> +
> +    target_filter = lock_user(VERIFY_READ, arg, sizeof(*target_filter), 1);
> +    if (!target_filter) {
> +        return -TARGET_EFAULT;
> +    }
> +    filter->flags = tswap16(target_filter->flags);
> +    filter->count = tswap16(target_filter->count);
> +    unlock_user(target_filter, arg, 0);
> +
> +    if (filter->count) {
> +        if (offsetof(struct tun_filter, addr) + filter->count * ETH_ALEN >
> +            MAX_STRUCT_SIZE) {
> +            return -TARGET_EFAULT;
> +        }
> +
> +        target_addr = lock_user(VERIFY_READ,
> +                                arg + offsetof(struct tun_filter, addr),
> +                                filter->count * ETH_ALEN, 1);
> +        if (!target_addr) {
> +            return -TARGET_EFAULT;
> +        }
> +        memcpy(filter->addr, target_addr, filter->count * ETH_ALEN);
> +        unlock_user(target_addr, arg + offsetof(struct tun_filter, addr),
> +                    filter->count * ETH_ALEN);
> +    }
> +
> +    return get_errno(safe_ioctl(fd, ie->host_cmd, filter));
> +}
> +
>  IOCTLEntry ioctl_entries[] = {
>  #define IOCTL(cmd, access, ...) \
>      { TARGET_ ## cmd, cmd, #cmd, access, 0, {  __VA_ARGS__ } },
> diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
> index 3c261cff0e..7ef0ff0328 100644
> --- a/linux-user/syscall_defs.h
> +++ b/linux-user/syscall_defs.h
> @@ -891,6 +891,38 @@ struct target_rtc_pll_info {
>  
>  #define TARGET_SIOCGIWNAME     0x8B01          /* get name == wireless 
> protocol */
>  
> +/* From <linux/if_tun.h> */
> +
> +#define TARGET_TUNSETDEBUG        TARGET_IOW('T', 201, int)
> +#define TARGET_TUNSETIFF          TARGET_IOW('T', 202, int)
> +#define TARGET_TUNSETPERSIST      TARGET_IOW('T', 203, int)
> +#define TARGET_TUNSETOWNER        TARGET_IOW('T', 204, int)
> +#define TARGET_TUNSETLINK         TARGET_IOW('T', 205, int)
> +#define TARGET_TUNSETGROUP        TARGET_IOW('T', 206, int)
> +#define TARGET_TUNGETFEATURES     TARGET_IOR('T', 207, unsigned int)
> +#define TARGET_TUNSETOFFLOAD      TARGET_IOW('T', 208, unsigned int)
> +#define TARGET_TUNSETTXFILTER     TARGET_IOW('T', 209, unsigned int)
> +#define TARGET_TUNGETIFF          TARGET_IOR('T', 210, unsigned int)
> +#define TARGET_TUNGETSNDBUF       TARGET_IOR('T', 211, int)
> +#define TARGET_TUNSETSNDBUF       TARGET_IOW('T', 212, int)
> +/*
> + * TUNATTACHFILTER and TUNDETACHFILTER are not supported. Linux kernel keeps 
> a
> + * user pointer in TUNATTACHFILTER, which we are not able to correctly 
> handle.
> + */
> +#define TARGET_TUNGETVNETHDRSZ    TARGET_IOR('T', 215, int)
> +#define TARGET_TUNSETVNETHDRSZ    TARGET_IOW('T', 216, int)
> +#define TARGET_TUNSETQUEUE        TARGET_IOW('T', 217, int)
> +#define TARGET_TUNSETIFINDEX      TARGET_IOW('T', 218, unsigned int)
> +/* TUNGETFILTER is not supported: see TUNATTACHFILTER. */
> +#define TARGET_TUNSETVNETLE       TARGET_IOW('T', 220, int)
> +#define TARGET_TUNGETVNETLE       TARGET_IOR('T', 221, int)
> +#define TARGET_TUNSETVNETBE       TARGET_IOW('T', 222, int)
> +#define TARGET_TUNGETVNETBE       TARGET_IOR('T', 223, int)
> +#define TARGET_TUNSETSTEERINGEBPF TARGET_IOR('T', 224, int)
> +#define TARGET_TUNSETFILTEREBPF   TARGET_IOR('T', 225, int)
> +#define TARGET_TUNSETCARRIER      TARGET_IOW('T', 226, int)
> +#define TARGET_TUNGETDEVNETNS     TARGET_IO('T', 227)
> +
>  /* From <linux/random.h> */
>  
>  #define TARGET_RNDGETENTCNT    TARGET_IOR('R', 0x00, int)
> 

Applied to my linux-user-for-6.0 branch

Thanks,
Laurent