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* Re: [syzbot] KMSAN: uninit-value in bpf_prog_run_generic_xdp
@ 2023-12-21 11:22 xingwei lee
  0 siblings, 0 replies; 2+ messages in thread
From: xingwei lee @ 2023-12-21 11:22 UTC (permalink / raw)
  To: syzbot+0e6ddb1ef80986bdfe64
  Cc: ben-linux, bp, daniel.sneddon, dave.hansen, glider, hpa,
	linux-kernel, mingo, pbonzini, sathyanarayanan.kuppuswamy,
	syzkaller-bugs, Thomas Gleixner, x86

Hello I reprudced this bug and comfirme triggered in the latest
net/bpf/bpf-next tree.

kernel: bpf-next fc3a5534e2a8855427403113cbeb54af5837bbe0
kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=4a65fa9f077ead01
with KMSAN enabled
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

=* repro.c =*
#define _GNU_SOURCE

#include <arpa/inet.h>
#include <dirent.h>
#include <endian.h>
#include <errno.h>
#include <fcntl.h>
#include <linux/capability.h>
#include <linux/genetlink.h>
#include <linux/if_addr.h>
#include <linux/if_ether.h>
#include <linux/if_link.h>
#include <linux/if_tun.h>
#include <linux/in6.h>
#include <linux/ip.h>
#include <linux/neighbour.h>
#include <linux/net.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include <linux/tcp.h>
#include <linux/veth.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <netinet/in.h>
#include <sched.h>
#include <signal.h>
#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mount.h>
#include <sys/prctl.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#ifndef __NR_bpf
#define __NR_bpf 321
#endif

static void sleep_ms(uint64_t ms) { usleep(ms * 1000); }

static uint64_t current_time_ms(void) {
 struct timespec ts;
 if (clock_gettime(CLOCK_MONOTONIC, &ts)) exit(1);
 return (uint64_t)ts.tv_sec * 1000 + (uint64_t)ts.tv_nsec / 1000000;
}

static bool write_file(const char* file, const char* what, ...) {
 char buf[1024];
 va_list args;
 va_start(args, what);
 vsnprintf(buf, sizeof(buf), what, args);
 va_end(args);
 buf[sizeof(buf) - 1] = 0;
 int len = strlen(buf);
 int fd = open(file, O_WRONLY | O_CLOEXEC);
 if (fd == -1) return false;
 if (write(fd, buf, len) != len) {
   int err = errno;
   close(fd);
   errno = err;
   return false;
 }
 close(fd);
 return true;
}

struct nlmsg {
 char* pos;
 int nesting;
 struct nlattr* nested[8];
 char buf[4096];
};

static void netlink_init(struct nlmsg* nlmsg, int typ, int flags,
                        const void* data, int size) {
 memset(nlmsg, 0, sizeof(*nlmsg));
 struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
 hdr->nlmsg_type = typ;
 hdr->nlmsg_flags = NLM_F_REQUEST | NLM_F_ACK | flags;
 memcpy(hdr + 1, data, size);
 nlmsg->pos = (char*)(hdr + 1) + NLMSG_ALIGN(size);
}

static void netlink_attr(struct nlmsg* nlmsg, int typ, const void* data,
                        int size) {
 struct nlattr* attr = (struct nlattr*)nlmsg->pos;
 attr->nla_len = sizeof(*attr) + size;
 attr->nla_type = typ;
 if (size > 0) memcpy(attr + 1, data, size);
 nlmsg->pos += NLMSG_ALIGN(attr->nla_len);
}

static int netlink_send_ext(struct nlmsg* nlmsg, int sock, uint16_t reply_type,
                           int* reply_len, bool dofail) {
 if (nlmsg->pos > nlmsg->buf + sizeof(nlmsg->buf) || nlmsg->nesting) exit(1);
 struct nlmsghdr* hdr = (struct nlmsghdr*)nlmsg->buf;
 hdr->nlmsg_len = nlmsg->pos - nlmsg->buf;
 struct sockaddr_nl addr;
 memset(&addr, 0, sizeof(addr));
 addr.nl_family = AF_NETLINK;
 ssize_t n = sendto(sock, nlmsg->buf, hdr->nlmsg_len, 0,
                    (struct sockaddr*)&addr, sizeof(addr));
 if (n != (ssize_t)hdr->nlmsg_len) {
   if (dofail) exit(1);
   return -1;
 }
 n = recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
 if (reply_len) *reply_len = 0;
 if (n < 0) {
   if (dofail) exit(1);
   return -1;
 }
 if (n < (ssize_t)sizeof(struct nlmsghdr)) {
   errno = EINVAL;
   if (dofail) exit(1);
   return -1;
 }
 if (hdr->nlmsg_type == NLMSG_DONE) return 0;
 if (reply_len && hdr->nlmsg_type == reply_type) {
   *reply_len = n;
   return 0;
 }
 if (n < (ssize_t)(sizeof(struct nlmsghdr) + sizeof(struct nlmsgerr))) {
   errno = EINVAL;
   if (dofail) exit(1);
   return -1;
 }
 if (hdr->nlmsg_type != NLMSG_ERROR) {
   errno = EINVAL;
   if (dofail) exit(1);
   return -1;
 }
 errno = -((struct nlmsgerr*)(hdr + 1))->error;
 return -errno;
}

static int netlink_send(struct nlmsg* nlmsg, int sock) {
 return netlink_send_ext(nlmsg, sock, 0, NULL, true);
}

static int netlink_query_family_id(struct nlmsg* nlmsg, int sock,
                                  const char* family_name, bool dofail) {
 struct genlmsghdr genlhdr;
 memset(&genlhdr, 0, sizeof(genlhdr));
 genlhdr.cmd = CTRL_CMD_GETFAMILY;
 netlink_init(nlmsg, GENL_ID_CTRL, 0, &genlhdr, sizeof(genlhdr));
 netlink_attr(nlmsg, CTRL_ATTR_FAMILY_NAME, family_name,
              strnlen(family_name, GENL_NAMSIZ - 1) + 1);
 int n = 0;
 int err = netlink_send_ext(nlmsg, sock, GENL_ID_CTRL, &n, dofail);
 if (err < 0) {
   return -1;
 }
 uint16_t id = 0;
 struct nlattr* attr = (struct nlattr*)(nlmsg->buf + NLMSG_HDRLEN +
                                        NLMSG_ALIGN(sizeof(genlhdr)));
 for (; (char*)attr < nlmsg->buf + n;
      attr = (struct nlattr*)((char*)attr + NLMSG_ALIGN(attr->nla_len))) {
   if (attr->nla_type == CTRL_ATTR_FAMILY_ID) {
     id = *(uint16_t*)(attr + 1);
     break;
   }
 }
 if (!id) {
   errno = EINVAL;
   return -1;
 }
 recv(sock, nlmsg->buf, sizeof(nlmsg->buf), 0);
 return id;
}

static void netlink_device_change(struct nlmsg* nlmsg, int sock,
                                 const char* name, bool up, const char* master,
                                 const void* mac, int macsize,
                                 const char* new_name) {
 struct ifinfomsg hdr;
 memset(&hdr, 0, sizeof(hdr));
 if (up) hdr.ifi_flags = hdr.ifi_change = IFF_UP;
 hdr.ifi_index = if_nametoindex(name);
 netlink_init(nlmsg, RTM_NEWLINK, 0, &hdr, sizeof(hdr));
 if (new_name) netlink_attr(nlmsg, IFLA_IFNAME, new_name, strlen(new_name));
 if (master) {
   int ifindex = if_nametoindex(master);
   netlink_attr(nlmsg, IFLA_MASTER, &ifindex, sizeof(ifindex));
 }
 if (macsize) netlink_attr(nlmsg, IFLA_ADDRESS, mac, macsize);
 int err = netlink_send(nlmsg, sock);
 if (err < 0) {
 }
}

static int netlink_add_addr(struct nlmsg* nlmsg, int sock, const char* dev,
                           const void* addr, int addrsize) {
 struct ifaddrmsg hdr;
 memset(&hdr, 0, sizeof(hdr));
 hdr.ifa_family = addrsize == 4 ? AF_INET : AF_INET6;
 hdr.ifa_prefixlen = addrsize == 4 ? 24 : 120;
 hdr.ifa_scope = RT_SCOPE_UNIVERSE;
 hdr.ifa_index = if_nametoindex(dev);
 netlink_init(nlmsg, RTM_NEWADDR, NLM_F_CREATE | NLM_F_REPLACE, &hdr,
              sizeof(hdr));
 netlink_attr(nlmsg, IFA_LOCAL, addr, addrsize);
 netlink_attr(nlmsg, IFA_ADDRESS, addr, addrsize);
 return netlink_send(nlmsg, sock);
}

static void netlink_add_addr4(struct nlmsg* nlmsg, int sock, const char* dev,
                             const char* addr) {
 struct in_addr in_addr;
 inet_pton(AF_INET, addr, &in_addr);
 int err = netlink_add_addr(nlmsg, sock, dev, &in_addr, sizeof(in_addr));
 if (err < 0) {
 }
}

static void netlink_add_addr6(struct nlmsg* nlmsg, int sock, const char* dev,
                             const char* addr) {
 struct in6_addr in6_addr;
 inet_pton(AF_INET6, addr, &in6_addr);
 int err = netlink_add_addr(nlmsg, sock, dev, &in6_addr, sizeof(in6_addr));
 if (err < 0) {
 }
}

static void netlink_add_neigh(struct nlmsg* nlmsg, int sock, const char* name,
                             const void* addr, int addrsize, const void* mac,
                             int macsize) {
 struct ndmsg hdr;
 memset(&hdr, 0, sizeof(hdr));
 hdr.ndm_family = addrsize == 4 ? AF_INET : AF_INET6;
 hdr.ndm_ifindex = if_nametoindex(name);
 hdr.ndm_state = NUD_PERMANENT;
 netlink_init(nlmsg, RTM_NEWNEIGH, NLM_F_EXCL | NLM_F_CREATE, &hdr,
              sizeof(hdr));
 netlink_attr(nlmsg, NDA_DST, addr, addrsize);
 netlink_attr(nlmsg, NDA_LLADDR, mac, macsize);
 int err = netlink_send(nlmsg, sock);
 if (err < 0) {
 }
}

static struct nlmsg nlmsg;

static int tunfd = -1;

#define TUN_IFACE "syz_tun"
#define LOCAL_MAC 0xaaaaaaaaaaaa
#define REMOTE_MAC 0xaaaaaaaaaabb
#define LOCAL_IPV4 "172.20.20.170"
#define REMOTE_IPV4 "172.20.20.187"
#define LOCAL_IPV6 "fe80::aa"
#define REMOTE_IPV6 "fe80::bb"

#define IFF_NAPI 0x0010

static void initialize_tun(void) {
 tunfd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
 if (tunfd == -1) {
   printf("tun: can't open /dev/net/tun: please enable CONFIG_TUN=y\n");
   printf("otherwise fuzzing or reproducing might not work as intended\n");
   return;
 }
 const int kTunFd = 200;
 if (dup2(tunfd, kTunFd) < 0) exit(1);
 close(tunfd);
 tunfd = kTunFd;
 struct ifreq ifr;
 memset(&ifr, 0, sizeof(ifr));
 strncpy(ifr.ifr_name, TUN_IFACE, IFNAMSIZ);
 ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 if (ioctl(tunfd, TUNSETIFF, (void*)&ifr) < 0) {
   exit(1);
 }
 char sysctl[64];
 sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/accept_dad", TUN_IFACE);
 write_file(sysctl, "0");
 sprintf(sysctl, "/proc/sys/net/ipv6/conf/%s/router_solicitations", TUN_IFACE);
 write_file(sysctl, "0");
 int sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
 if (sock == -1) exit(1);
 netlink_add_addr4(&nlmsg, sock, TUN_IFACE, LOCAL_IPV4);
 netlink_add_addr6(&nlmsg, sock, TUN_IFACE, LOCAL_IPV6);
 uint64_t macaddr = REMOTE_MAC;
 struct in_addr in_addr;
 inet_pton(AF_INET, REMOTE_IPV4, &in_addr);
 netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in_addr, sizeof(in_addr),
                   &macaddr, ETH_ALEN);
 struct in6_addr in6_addr;
 inet_pton(AF_INET6, REMOTE_IPV6, &in6_addr);
 netlink_add_neigh(&nlmsg, sock, TUN_IFACE, &in6_addr, sizeof(in6_addr),
                   &macaddr, ETH_ALEN);
 macaddr = LOCAL_MAC;
 netlink_device_change(&nlmsg, sock, TUN_IFACE, true, 0, &macaddr, ETH_ALEN,
                       NULL);
 close(sock);
}

static int read_tun(char* data, int size) {
 if (tunfd < 0) return -1;
 int rv = read(tunfd, data, size);
 if (rv < 0) {
   if (errno == EAGAIN || errno == EBADFD) return -1;
   exit(1);
 }
 return rv;
}

static long syz_emit_ethernet(volatile long a0, volatile long a1,
                             volatile long a2) {
 if (tunfd < 0) return (uintptr_t)-1;
 uint32_t length = a0;
 char* data = (char*)a1;
 return write(tunfd, data, length);
}

static void flush_tun() {
 char data[1000];
 while (read_tun(&data[0], sizeof(data)) != -1) {
 }
}

#define MAX_FDS 30

static void setup_common() {
 if (mount(0, "/sys/fs/fuse/connections", "fusectl", 0, 0)) {
 }
}

static void setup_binderfs() {
 if (mkdir("/dev/binderfs", 0777)) {
 }
 if (mount("binder", "/dev/binderfs", "binder", 0, NULL)) {
 }
 if (symlink("/dev/binderfs", "./binderfs")) {
 }
}

static void loop();

static void sandbox_common() {
 prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
 setsid();
 struct rlimit rlim;
 rlim.rlim_cur = rlim.rlim_max = (200 << 20);
 setrlimit(RLIMIT_AS, &rlim);
 rlim.rlim_cur = rlim.rlim_max = 32 << 20;
 setrlimit(RLIMIT_MEMLOCK, &rlim);
 rlim.rlim_cur = rlim.rlim_max = 136 << 20;
 setrlimit(RLIMIT_FSIZE, &rlim);
 rlim.rlim_cur = rlim.rlim_max = 1 << 20;
 setrlimit(RLIMIT_STACK, &rlim);
 rlim.rlim_cur = rlim.rlim_max = 128 << 20;
 setrlimit(RLIMIT_CORE, &rlim);
 rlim.rlim_cur = rlim.rlim_max = 256;
 setrlimit(RLIMIT_NOFILE, &rlim);
 if (unshare(CLONE_NEWNS)) {
 }
 if (mount(NULL, "/", NULL, MS_REC | MS_PRIVATE, NULL)) {
 }
 if (unshare(CLONE_NEWIPC)) {
 }
 if (unshare(0x02000000)) {
 }
 if (unshare(CLONE_NEWUTS)) {
 }
 if (unshare(CLONE_SYSVSEM)) {
 }
 typedef struct {
   const char* name;
   const char* value;
 } sysctl_t;
 static const sysctl_t sysctls[] = {
     {"/proc/sys/kernel/shmmax", "16777216"},
     {"/proc/sys/kernel/shmall", "536870912"},
     {"/proc/sys/kernel/shmmni", "1024"},
     {"/proc/sys/kernel/msgmax", "8192"},
     {"/proc/sys/kernel/msgmni", "1024"},
     {"/proc/sys/kernel/msgmnb", "1024"},
     {"/proc/sys/kernel/sem", "1024 1048576 500 1024"},
 };
 unsigned i;
 for (i = 0; i < sizeof(sysctls) / sizeof(sysctls[0]); i++)
   write_file(sysctls[i].name, sysctls[i].value);
}

static int wait_for_loop(int pid) {
 if (pid < 0) exit(1);
 int status = 0;
 while (waitpid(-1, &status, __WALL) != pid) {
 }
 return WEXITSTATUS(status);
}

static void drop_caps(void) {
 struct __user_cap_header_struct cap_hdr = {};
 struct __user_cap_data_struct cap_data[2] = {};
 cap_hdr.version = _LINUX_CAPABILITY_VERSION_3;
 cap_hdr.pid = getpid();
 if (syscall(SYS_capget, &cap_hdr, &cap_data)) exit(1);
 const int drop = (1 << CAP_SYS_PTRACE) | (1 << CAP_SYS_NICE);
 cap_data[0].effective &= ~drop;
 cap_data[0].permitted &= ~drop;
 cap_data[0].inheritable &= ~drop;
 if (syscall(SYS_capset, &cap_hdr, &cap_data)) exit(1);
}

static int do_sandbox_none(void) {
 if (unshare(CLONE_NEWPID)) {
 }
 int pid = fork();
 if (pid != 0) return wait_for_loop(pid);
 setup_common();
 sandbox_common();
 drop_caps();
 if (unshare(CLONE_NEWNET)) {
 }
 write_file("/proc/sys/net/ipv4/ping_group_range", "0 65535");
 initialize_tun();
 setup_binderfs();
 loop();
 exit(1);
}

static void kill_and_wait(int pid, int* status) {
 kill(-pid, SIGKILL);
 kill(pid, SIGKILL);
 for (int i = 0; i < 100; i++) {
   if (waitpid(-1, status, WNOHANG | __WALL) == pid) return;
   usleep(1000);
 }
 DIR* dir = opendir("/sys/fs/fuse/connections");
 if (dir) {
   for (;;) {
     struct dirent* ent = readdir(dir);
     if (!ent) break;
     if (strcmp(ent->d_name, ".") == 0 || strcmp(ent->d_name, "..") == 0)
       continue;
     char abort[300];
     snprintf(abort, sizeof(abort), "/sys/fs/fuse/connections/%s/abort",
              ent->d_name);
     int fd = open(abort, O_WRONLY);
     if (fd == -1) {
       continue;
     }
     if (write(fd, abort, 1) < 0) {
     }
     close(fd);
   }
   closedir(dir);
 } else {
 }
 while (waitpid(-1, status, __WALL) != pid) {
 }
}

static void setup_test() {
 prctl(PR_SET_PDEATHSIG, SIGKILL, 0, 0, 0);
 setpgrp();
 write_file("/proc/self/oom_score_adj", "1000");
 flush_tun();
}

static void close_fds() {
 for (int fd = 3; fd < MAX_FDS; fd++) close(fd);
}

static void execute_one(void);

#define WAIT_FLAGS __WALL

static void loop(void) {
 int iter = 0;
 for (;; iter++) {
   int pid = fork();
   if (pid < 0) exit(1);
   if (pid == 0) {
     setup_test();
     execute_one();
     close_fds();
     exit(0);
   }
   int status = 0;
   uint64_t start = current_time_ms();
   for (;;) {
     if (waitpid(-1, &status, WNOHANG | WAIT_FLAGS) == pid) break;
     sleep_ms(1);
     if (current_time_ms() - start < 5000) continue;
     kill_and_wait(pid, &status);
     break;
   }
 }
}

uint64_t r[3] = {0xffffffffffffffff, 0xffffffffffffffff, 0x0};

void execute_one(void) {
 intptr_t res = 0;
 res = syscall(__NR_socket, /*domain=*/2ul, /*type=*/1ul, /*proto=*/0);
 if (res != -1) r[0] = res;
 *(uint32_t*)0x20000100 = 6;
 *(uint32_t*)0x20000104 = 4;
 *(uint64_t*)0x20000108 = 0x20000200;
 memcpy((void*)0x20000200,
        "\x18\x02\x00\x00\xfd\xff\xff\xff\x00\x00\x00\x00\x00\x00\x00\x00\x85"
        "\x00\x00\x00\x2c\x00\x00\x00\x95",
        25);
 *(uint64_t*)0x20000110 = 0x20000040;
 memcpy((void*)0x20000040, "GPL\000", 4);
 *(uint32_t*)0x20000118 = 0;
 *(uint32_t*)0x2000011c = 0;
 *(uint64_t*)0x20000120 = 0;
 *(uint32_t*)0x20000128 = 0;
 *(uint32_t*)0x2000012c = 0;
 memset((void*)0x20000130, 0, 16);
 *(uint32_t*)0x20000140 = 0;
 *(uint32_t*)0x20000144 = 0;
 *(uint32_t*)0x20000148 = -1;
 *(uint32_t*)0x2000014c = 8;
 *(uint64_t*)0x20000150 = 0;
 *(uint32_t*)0x20000158 = 0;
 *(uint32_t*)0x2000015c = 0x10;
 *(uint64_t*)0x20000160 = 0;
 *(uint32_t*)0x20000168 = 0;
 *(uint32_t*)0x2000016c = 0;
 *(uint32_t*)0x20000170 = 0;
 *(uint32_t*)0x20000174 = 0;
 *(uint64_t*)0x20000178 = 0;
 *(uint64_t*)0x20000180 = 0;
 *(uint32_t*)0x20000188 = 0x10;
 *(uint32_t*)0x2000018c = 0;
 res = syscall(__NR_bpf, /*cmd=*/5ul, /*arg=*/0x20000100ul, /*size=*/0x90ul);
 if (res != -1) r[1] = res;
 memcpy((void*)0x20000180, "syz_tun\000\000\000\000\000\000\000\000\000", 16);
 res = syscall(__NR_ioctl, /*fd=*/r[0], /*cmd=*/0x8933, /*arg=*/0x20000180ul);
 if (res != -1) r[2] = *(uint32_t*)0x20000190;
 *(uint32_t*)0x20000000 = r[1];
 *(uint32_t*)0x20000004 = r[2];
 *(uint32_t*)0x20000008 = 0x25;
 *(uint32_t*)0x2000000c = 0;
 *(uint32_t*)0x20000010 = 0;
 syscall(__NR_bpf, /*cmd=*/0x1cul, /*arg=*/0x20000000ul, /*size=*/0x10ul);
 memset((void*)0x20000f00, 170, 5);
 *(uint8_t*)0x20000f05 = 0xaa;
 memset((void*)0x20000f06, 0, 6);
 *(uint16_t*)0x20000f0c = htobe16(0);
 syz_emit_ethernet(/*len=*/0xfdef, /*packet=*/0x20000f00, /*frags=*/0);
}
int main(void) {
 syscall(__NR_mmap, /*addr=*/0x1ffff000ul, /*len=*/0x1000ul, /*prot=*/0ul,
         /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
 syscall(__NR_mmap, /*addr=*/0x20000000ul, /*len=*/0x1000000ul, /*prot=*/7ul,
         /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
 syscall(__NR_mmap, /*addr=*/0x21000000ul, /*len=*/0x1000ul, /*prot=*/0ul,
         /*flags=*/0x32ul, /*fd=*/-1, /*offset=*/0ul);
 do_sandbox_none();
 return 0;
}


=* repro.txt =*
r0 = socket$inet_tcp(0x2, 0x1, 0x0)
r1 = bpf$BPF_PROG_RAW_TRACEPOINT_LOAD(0x5, &(0x7f0000000100)={0x6,
0x4, &(0x7f0000000200)=ANY=[@ANYBLOB="18020000fdffffff0000000000000000850000002c00000095"],
&(0x7f0000000040)='GPL\x00'}, 0x90)
ioctl$sock_SIOCGIFINDEX(r0, 0x8933, &(0x7f0000000180)={'syz_tun\x00', <r2=>0x0})
bpf$BPF_LINK_CREATE_XDP(0x1c, &(0x7f0000000000)={r1, r2}, 0x10)
syz_emit_ethernet(0xfdef, &(0x7f0000000f00)={@local, @empty, @void}, 0x0)


See aslo https://gist.github.com/xrivendell7/c971ada013151e3b5a5f3f69f8f9ce63

I hope it helps.

Best regards.
xingwei Lee

^ permalink raw reply	[flat|nested] 2+ messages in thread

* [syzbot] KMSAN: uninit-value in bpf_prog_run_generic_xdp
@ 2022-11-18 11:39 syzbot
  0 siblings, 0 replies; 2+ messages in thread
From: syzbot @ 2022-11-18 11:39 UTC (permalink / raw)
  To: ben-linux, bp, daniel.sneddon, dave.hansen, glider, hpa,
	linux-kernel, mingo, pbonzini, sathyanarayanan.kuppuswamy,
	syzkaller-bugs, tglx, x86

Hello,

syzbot found the following issue on:

HEAD commit:    cb231e2f67ec fs: more fsdata fixes
git tree:       https://github.com/google/kmsan.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=14ef6401880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dc6d7125db95a828
dashboard link: https://syzkaller.appspot.com/bug?extid=0e6ddb1ef80986bdfe64
compiler:       clang version 15.0.0 (https://github.com/llvm/llvm-project.git 610139d2d9ce6746b3c617fb3e2f7886272d26ff), GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: i386

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/6eabbc575a06/disk-cb231e2f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/01e99c04e1d7/vmlinux-cb231e2f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/67893482166a/bzImage-cb231e2f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+0e6ddb1ef80986bdfe64@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x13ff/0x1a30 net/core/dev.c:4782
 bpf_prog_run_generic_xdp+0x13ff/0x1a30 net/core/dev.c:4782
 netif_receive_generic_xdp+0x639/0x910 net/core/dev.c:4845
 do_xdp_generic net/core/dev.c:4904 [inline]
 __netif_receive_skb_core+0x290f/0x6360 net/core/dev.c:5310
 __netif_receive_skb_one_core net/core/dev.c:5487 [inline]
 __netif_receive_skb+0xc8/0x5d0 net/core/dev.c:5603
 process_backlog+0x45a/0x890 net/core/dev.c:5931
 __napi_poll+0xe6/0x920 net/core/dev.c:6498
 napi_poll net/core/dev.c:6565 [inline]
 net_rx_action+0x9e8/0x1a20 net/core/dev.c:6676
 __do_softirq+0x1c5/0x7b9 kernel/softirq.c:571
 invoke_softirq+0x8f/0x100 kernel/softirq.c:445
 __irq_exit_rcu+0x5a/0x110 kernel/softirq.c:650
 irq_exit_rcu+0xe/0x10 kernel/softirq.c:662
 sysvec_apic_timer_interrupt+0x9a/0xc0 arch/x86/kernel/apic/apic.c:1107
 asm_sysvec_apic_timer_interrupt+0x1b/0x20 arch/x86/include/asm/idtentry.h:649
 kmsan_get_shadow_origin_ptr+0x34/0xa0 mm/kmsan/shadow.c:97
 get_shadow_origin_ptr mm/kmsan/instrumentation.c:36 [inline]
 __msan_metadata_ptr_for_load_8+0x20/0x30 mm/kmsan/instrumentation.c:78
 unwind_get_return_address_ptr+0x97/0xc0 arch/x86/kernel/unwind_frame.c:28
 update_stack_state+0x177/0x1e0 arch/x86/kernel/unwind_frame.c:251
 unwind_next_frame+0x119/0x360 arch/x86/kernel/unwind_frame.c:315
 arch_stack_walk+0x1b9/0x280 arch/x86/kernel/stacktrace.c:25
 stack_trace_save+0xb2/0x100 kernel/stacktrace.c:122
 kmsan_save_stack_with_flags mm/kmsan/core.c:75 [inline]
 kmsan_internal_poison_memory+0x45/0x90 mm/kmsan/core.c:60
 kmsan_slab_free+0xcd/0x130 mm/kmsan/hooks.c:90
 slab_free_hook mm/slub.c:1694 [inline]
 slab_free_freelist_hook mm/slub.c:1750 [inline]
 slab_free mm/slub.c:3661 [inline]
 kmem_cache_free+0x365/0xdb0 mm/slub.c:3683
 security_file_free+0x15d/0x1a0 security/security.c:1548
 file_free fs/file_table.c:56 [inline]
 __fput+0xbed/0xea0 fs/file_table.c:333
 ____fput+0x1a/0x20 fs/file_table.c:348
 task_work_run+0x229/0x2c0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x2a9/0x320 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x16e/0x220 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x23/0x40 kernel/entry/common.c:296
 __do_fast_syscall_32+0xb1/0x100 arch/x86/entry/common.c:181
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:742 [inline]
 slab_alloc_node mm/slub.c:3398 [inline]
 __kmem_cache_alloc_node+0x6ee/0xc90 mm/slub.c:3437
 __do_kmalloc_node mm/slab_common.c:954 [inline]
 __kmalloc_node_track_caller+0x117/0x3d0 mm/slab_common.c:975
 kmalloc_reserve net/core/skbuff.c:437 [inline]
 pskb_expand_head+0x23d/0x1970 net/core/skbuff.c:1832
 netif_receive_generic_xdp+0x4c6/0x910 net/core/dev.c:4837
 do_xdp_generic net/core/dev.c:4904 [inline]
 __netif_receive_skb_core+0x290f/0x6360 net/core/dev.c:5310
 __netif_receive_skb_one_core net/core/dev.c:5487 [inline]
 __netif_receive_skb+0xc8/0x5d0 net/core/dev.c:5603
 process_backlog+0x45a/0x890 net/core/dev.c:5931
 __napi_poll+0xe6/0x920 net/core/dev.c:6498
 napi_poll net/core/dev.c:6565 [inline]
 net_rx_action+0x9e8/0x1a20 net/core/dev.c:6676
 __do_softirq+0x1c5/0x7b9 kernel/softirq.c:571

CPU: 0 PID: 3506 Comm: syz-executor.2 Tainted: G        W          6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================


---
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end of thread, other threads:[~2023-12-21 11:22 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
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2023-12-21 11:22 [syzbot] KMSAN: uninit-value in bpf_prog_run_generic_xdp xingwei lee
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2022-11-18 11:39 syzbot

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