We report a bug in linux-4.19.13: "UBSAN: Undefined behaviour in net/can/bcm.c" kernel config: https://kt0755.github.io/etc/config_4.19.13 repro: https://kt0755.github.io/etc/repro.296b5.c An integer overflow arose in bcm_timeval_to_ktime() when tv.tv_usec * NSEC_PER_USEC is larger than its boundary of the destination (i.e., long). To fix, an appropriate boundary check should be placed right before the usage. ========================================= UBSAN: Undefined behaviour in net/can/bcm.c:140:41 signed integer overflow: 60870466536963773 * 1000 cannot be represented in type 'long int' CPU: 0 PID: 7063 Comm: syz-executor3 Not tainted 4.19.13 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xd2/0x148 lib/dump_stack.c:113 ubsan_epilogue+0x12/0x94 lib/ubsan.c:159 handle_overflow+0x1cf/0x21a lib/ubsan.c:190 __ubsan_handle_mul_overflow+0x2a/0x35 lib/ubsan.c:214 bcm_timeval_to_ktime net/can/bcm.c:140 [inline] bcm_rx_setup net/can/bcm.c:1190 [inline] bcm_sendmsg+0x3807/0x3fd0 net/can/bcm.c:1355 sock_sendmsg_nosec net/socket.c:621 [inline] sock_sendmsg+0xdd/0x130 net/socket.c:631 sock_write_iter+0x24b/0x3d0 net/socket.c:900 call_write_iter include/linux/fs.h:1811 [inline] new_sync_write fs/read_write.c:474 [inline] __vfs_write+0x538/0x6e0 fs/read_write.c:487 vfs_write+0x1b3/0x520 fs/read_write.c:549 ksys_write+0xde/0x1c0 fs/read_write.c:598 __do_sys_write fs/read_write.c:610 [inline] __se_sys_write fs/read_write.c:607 [inline] __x64_sys_write+0x7e/0xc0 fs/read_write.c:607 do_syscall_64+0xc4/0x510 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4497b9 Code: e8 8c 9f 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 9b 6b fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fc2e6feac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fc2e6feb6cc RCX: 00000000004497b9 RDX: 0000000000000048 RSI: 00000000200000c0 RDI: 0000000000000013 RBP: 000000000071bea0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 000000000000ba60 R14: 00000000006f4b00 R15: 00007fc2e6feb700 ========================================= Thanks, Kyungtae Kim
