[bug report] memory corruption panic caused by SG_IO ioctl()

[Wanlong Gao]

Hi Martin and all folks,

Recently we find a kernel panic with memory corruption caused by SG_IO ioctl(), and it can be easily reproduced by running following reproducer about minutes,  any idea?

 

Thanks,

Wanlong

C reproducer:

// autogenerated by syzkaller (http://github.com/google/syzkaller)

 

#define _GNU_SOURCE

#include <endian.h>

#include <sys/syscall.h>

#include <unistd.h>

#include <fcntl.h>

#include <stdio.h>

#include <string.h>

#include <sys/stat.h>

#include <stdint.h>

#include <string.h>

 

static uintptr_t syz_open_dev(uintptr_t a0, uintptr_t a1, uintptr_t a2)

{

if (a0 == 0xc || a0 == 0xb) {

char buf[128];

sprintf(buf, "/dev/%s/%d:%d", a0 == 0xc ? "char" : "block", (uint8_t)a1, (uint8_t)a2);

return open(buf, O_RDWR, 0);

} else {

char buf[1024];

char* hash;

strncpy(buf, (char*)a0, sizeof(buf) - 1);

buf[sizeof(buf) - 1] = 0;

while ((hash = strchr(buf, '#'))) {

*hash = '0' + (char)(a1 % 10);

a1 /= 10;

}

return open(buf, a2, 0);

}

}

 

static void execute_one();

extern unsigned long long procid;

 

void loop()

{

while (1) {

execute_one();

}

}

 

uint64_t r[1] = {0xffffffffffffffff};

void execute_one()

{

long res = 0;

memcpy((void*)0x20000040, "/dev/sg#", 9);

res = syz_open_dev(0x20000040, 0, 0);

if (res != -1)

r[0] = res;

*(uint32_t*)0x200002c0 = 0x53;

*(uint32_t*)0x200002c4 = 0;

*(uint8_t*)0x200002c8 = 0xd;

*(uint8_t*)0x200002c9 = 0;

*(uint16_t*)0x200002ca = 0;

*(uint32_t*)0x200002cc = 0x95;

*(uint64_t*)0x200002d0 = 0x20000080;

*(uint64_t*)0x200002d8 = 0x20000000;

memcpy((void*)0x20000000, "\x08\xf0\xa8\x77\xd3\xbe\x87\x5d\xda\x65\x79\x3f\xc7", 13);

*(uint64_t*)0x200002e0 = 0x20000180;

*(uint32_t*)0x200002e8 = 0x8001;

*(uint32_t*)0x200002ec = 0x10024;

*(uint32_t*)0x200002f0 = -1;

*(uint64_t*)0x200002f4 = 0x20000280;

*(uint8_t*)0x200002fc = 0;

*(uint8_t*)0x200002fd = 0;

*(uint8_t*)0x200002fe = 0;

*(uint8_t*)0x200002ff = 0;

*(uint16_t*)0x20000300 = 0;

*(uint16_t*)0x20000302 = 0;

*(uint32_t*)0x20000304 = 0;

*(uint32_t*)0x20000308 = 0;

*(uint32_t*)0x2000030c = 0;

syscall(__NR_ioctl, r[0], 0x2285, 0x200002c0);

}

 

int main()

{

syscall(__NR_mmap, 0x20000000, 0x1000000, 3, 0x32, -1, 0);

for (;;) {

loop();

}

}