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KMSAN: uninit-value in ipgre_xmit #20

Closed yshigeru closed 7 months ago

yshigeru commented 7 months ago 
=====================================================
BUG: KMSAN: uninit-value in __gre_xmit net/ipv4/ip_gre.c:469 [inline]
BUG: KMSAN: uninit-value in ipgre_xmit+0xdf4/0xe70 net/ipv4/ip_gre.c:662
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0xdf4/0xe70 net/ipv4/ip_gre.c:662
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3543 [inline]
 dev_hard_start_xmit+0x24a/0xa10 net/core/dev.c:3559
 __dev_queue_xmit+0x32f6/0x50e0 net/core/dev.c:4344
 dev_queue_xmit include/linux/netdevice.h:3112 [inline]
 packet_xmit+0x8f/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3087 [inline]
 packet_sendmsg+0x8c24/0x9aa0 net/packet/af_packet.c:3119
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x717/0xa00 net/socket.c:2194
 __do_sys_sendto net/socket.c:2206 [inline]
 __se_sys_sendto net/socket.c:2202 [inline]
 __x64_sys_sendto+0x130/0x200 net/socket.c:2202
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was stored to memory at:
 __gre_xmit net/ipv4/ip_gre.c:469 [inline]
 ipgre_xmit+0xded/0xe70 net/ipv4/ip_gre.c:662
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3543 [inline]
 dev_hard_start_xmit+0x24a/0xa10 net/core/dev.c:3559
 __dev_queue_xmit+0x32f6/0x50e0 net/core/dev.c:4344
 dev_queue_xmit include/linux/netdevice.h:3112 [inline]
 packet_xmit+0x8f/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3087 [inline]
 packet_sendmsg+0x8c24/0x9aa0 net/packet/af_packet.c:3119
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x717/0xa00 net/socket.c:2194
 __do_sys_sendto net/socket.c:2206 [inline]
 __se_sys_sendto net/socket.c:2202 [inline]
 __x64_sys_sendto+0x130/0x200 net/socket.c:2202
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 slab_post_alloc_hook+0x103/0x9e0 mm/slab.h:768
 slab_alloc_node mm/slub.c:3478 [inline]
 kmem_cache_alloc_node+0x5f7/0xb50 mm/slub.c:3523
 kmalloc_reserve+0x13c/0x4a0 net/core/skbuff.c:560
 pskb_expand_head+0x20b/0x19a0 net/core/skbuff.c:2098
 __skb_cow include/linux/skbuff.h:3586 [inline]
 skb_cow_head include/linux/skbuff.h:3620 [inline]
 ipgre_xmit+0x73c/0xe70 net/ipv4/ip_gre.c:638
 __netdev_start_xmit include/linux/netdevice.h:4918 [inline]
 netdev_start_xmit include/linux/netdevice.h:4932 [inline]
 xmit_one net/core/dev.c:3543 [inline]
 dev_hard_start_xmit+0x24a/0xa10 net/core/dev.c:3559
 __dev_queue_xmit+0x32f6/0x50e0 net/core/dev.c:4344
 dev_queue_xmit include/linux/netdevice.h:3112 [inline]
 packet_xmit+0x8f/0x6b0 net/packet/af_packet.c:276
 packet_snd net/packet/af_packet.c:3087 [inline]
 packet_sendmsg+0x8c24/0x9aa0 net/packet/af_packet.c:3119
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x717/0xa00 net/socket.c:2194
 __do_sys_sendto net/socket.c:2206 [inline]
 __se_sys_sendto net/socket.c:2202 [inline]
 __x64_sys_sendto+0x130/0x200 net/socket.c:2202
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 11318 Comm: syz-executor.7 Not tainted 6.6.0-14500-g1c41041124bd #10
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-1.fc38 04/01/2014
=====================================================
yshigeru commented 7 months ago

repro.c.gz

yshigeru commented 7 months ago

Simplified version of repro:

#include <linux/if_ether.h>
#include <sys/ioctl.h>
#include <netinet/ether.h>
#include <net/if.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <linux/if_packet.h>

int main(void)
{
    int s1, s2, data = 0;
    struct ifreq ifr;
    struct sockaddr_ll addr = { 0 };
    unsigned char mac_addr[] = {0x1, 0x2, 0x3, 0x4, 0x5, 0x6};

    s1 = socket(AF_PACKET, SOCK_RAW, 0);
    s2 = socket(AF_NETLINK, SOCK_RAW, 0);

    strcpy(ifr.ifr_name, "gre0");
    ioctl(s2, SIOCGIFINDEX, &ifr);

    addr.sll_family = AF_PACKET;
    addr.sll_ifindex = ifr.ifr_ifindex;
    addr.sll_protocol = htons(0);
    addr.sll_hatype = ARPHRD_ETHER;
    addr.sll_pkttype = PACKET_HOST;
    addr.sll_halen = ETH_ALEN;
    memcpy(addr.sll_addr, mac_addr, ETH_ALEN);

    sendto(s1, &data, 1, 0, (struct sockaddr *)&addr, sizeof(addr));

    return 0;
}
yshigeru commented 7 months ago

Sent a patch: https://lore.kernel.org/all/20231126151652.372783-1-syoshida@redhat.com/

yshigeru commented 7 months ago

Sent v2 patch: https://lore.kernel.org/all/20231202161441.221135-1-syoshida@redhat.com/

yshigeru commented 7 months ago

Merged on net tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=80d875cfc9d3