lkml.org 
[lkml]   [2021]   [Apr]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 54/66] net: tun: set tun->dev->addr_len during TUNSETLINK processing
    Date
    From: Phillip Potter <phil@philpotter.co.uk>

    commit cca8ea3b05c972ffb5295367e6c544369b45fbdd upstream.

    When changing type with TUNSETLINK ioctl command, set tun->dev->addr_len
    to match the appropriate type, using new tun_get_addr_len utility function
    which returns appropriate address length for given type. Fixes a
    KMSAN-found uninit-value bug reported by syzbot at:
    https://syzkaller.appspot.com/bug?id=0766d38c656abeace60621896d705743aeefed51

    Reported-by: syzbot+001516d86dbe88862cec@syzkaller.appspotmail.com
    Diagnosed-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
    Reviewed-by: Eric Dumazet <edumazet@google.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/net/tun.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
    1 file changed, 48 insertions(+)

    --- a/drivers/net/tun.c
    +++ b/drivers/net/tun.c
    @@ -77,6 +77,14 @@
    #include <linux/bpf.h>
    #include <linux/bpf_trace.h>
    #include <linux/mutex.h>
    +#include <linux/ieee802154.h>
    +#include <linux/if_ltalk.h>
    +#include <uapi/linux/if_fddi.h>
    +#include <uapi/linux/if_hippi.h>
    +#include <uapi/linux/if_fc.h>
    +#include <net/ax25.h>
    +#include <net/rose.h>
    +#include <net/6lowpan.h>

    #include <linux/uaccess.h>
    #include <linux/proc_fs.h>
    @@ -2864,6 +2872,45 @@ static int tun_set_ebpf(struct tun_struc
    return __tun_set_ebpf(tun, prog_p, prog);
    }

    +/* Return correct value for tun->dev->addr_len based on tun->dev->type. */
    +static unsigned char tun_get_addr_len(unsigned short type)
    +{
    + switch (type) {
    + case ARPHRD_IP6GRE:
    + case ARPHRD_TUNNEL6:
    + return sizeof(struct in6_addr);
    + case ARPHRD_IPGRE:
    + case ARPHRD_TUNNEL:
    + case ARPHRD_SIT:
    + return 4;
    + case ARPHRD_ETHER:
    + return ETH_ALEN;
    + case ARPHRD_IEEE802154:
    + case ARPHRD_IEEE802154_MONITOR:
    + return IEEE802154_EXTENDED_ADDR_LEN;
    + case ARPHRD_PHONET_PIPE:
    + case ARPHRD_PPP:
    + case ARPHRD_NONE:
    + return 0;
    + case ARPHRD_6LOWPAN:
    + return EUI64_ADDR_LEN;
    + case ARPHRD_FDDI:
    + return FDDI_K_ALEN;
    + case ARPHRD_HIPPI:
    + return HIPPI_ALEN;
    + case ARPHRD_IEEE802:
    + return FC_ALEN;
    + case ARPHRD_ROSE:
    + return ROSE_ADDR_LEN;
    + case ARPHRD_NETROM:
    + return AX25_ADDR_LEN;
    + case ARPHRD_LOCALTLK:
    + return LTALK_ALEN;
    + default:
    + return 0;
    + }
    +}
    +
    static long __tun_chr_ioctl(struct file *file, unsigned int cmd,
    unsigned long arg, int ifreq_len)
    {
    @@ -3018,6 +3065,7 @@ static long __tun_chr_ioctl(struct file
    ret = -EBUSY;
    } else {
    tun->dev->type = (int) arg;
    + tun->dev->addr_len = tun_get_addr_len(tun->dev->type);
    tun_debug(KERN_INFO, tun, "linktype set to %d\n",
    tun->dev->type);
    ret = 0;

    \
     
     \ /
      Last update: 2021-04-12 11:11    [W:4.577 / U:0.088 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site