If the logger instance does not use log groups (i.e. pGroups in __libc_LogInit[Ex] is NULL which is perfectly legal), an attempt to write out anything into the log file will result in a truncated log header:
Opened log at 2021-08-19 17:16:13.48 (00d15a79 ms since boot)
Process ID: 0xbbb (3003) Parent PID: 0xbba (3002) Type: 2
Exe hmte : 0x50a (D:\CODING\LIBCX\MASTER-BUILD\STAGE\BIN\LIBCX-STATS.EXE)
Arg 0 : libcx-stats
Cur dir : C:\var\log\app
CRT Module: LIBCN0 hmod=0xb82 (C:\USR\LIB\LIBCN0.DLL)
__libc_logInit: addr 0x1e07f8a9 iObj=0 offObj=0x4f8a9
Origin : libcx
Enabled groups:
and a crash in LIBC:
Filename: C:\USR\LIB\LIBCN0.DLL (08/16/2021 23:44:02 1,225,146)
Address: 005B:1E08008E (0001:0005008E)
Cause: Attempted to read from 00000004
(not a valid address)
______________________________________________________________________
Failing Instruction
______________________________________________________________________
1E080080 MOV EAX, [EDI+0x4] (8b47 04)
1E080083 MOV [ESP], EAX (890424)
1E080086 CALL 0x1ffc5e28 (e8 9d5df401)
1E08008B MOV EAX, [EDI+0x8] (8b47 08)
1E08008E >MOV ECX, [EAX+0x4] (8b48 04)
1E080091 TEST ECX, ECX (85c9)
1E080093 JZ 0x1e080668 (0f84 cf050000)
1E080099 MOV DWORD [EBP-0x25c], 0x0 (c785 a4fdffff 00000000)
______________________________________________________________________
Registers
______________________________________________________________________
EAX : 00000000 EBX : 0012F3F0 ECX : 0012F638 EDX : 000001CB
ESI : 20034614 EDI : 20034600
ESP : 0012F3A0 EBP : 0012F878 EIP : 1E08008E EFLG : 00010293
CS : 005B CSLIM: FFFFFFFF SS : 0053 SSLIM: FFFFFFFF
EAX : not a valid address
EBX : read/write memory on this thread's stack
ECX : read/write memory on this thread's stack
EDX : not a valid address
ESI : read/write memory allocated by LIBCN0
EDI : read/write memory allocated by LIBCN0
...
EBP Address Module Obj:Offset Nearest Public Symbol
-------- --------- -------- ------------- -----------------------
Trap -> 1E08008E LIBCN0 0001:0005008E logstrict.c#742 ___libc_LogSNPrintf + B3D 0001:0004F551 (logstrict.obj)
0012F878 1E080959 LIBCN0 0001:00050959 logstrict.c#442 ___libc_LogInitEx + E1 0001:00050878 (logstrict.obj)
The crash happens because when LIBC writes enabled log groups to the header, it doesn't check if pGroups is NULL before accessing it and hence the crash.
This is a regression of a9eb83452cb2b814b77cdac82c985f46a1188fb3.
The problem is rather critical as it completely breaks LIBCx assertion logging and will even result into shadowing a proper EXCEPTQ report (related to the LIBCx assertion) with LIBC own (shown above), see https://github.com/bitwiseworks/libcx/issues/98. Needs an urgent fix.
If the logger instance does not use log groups (i.e.
pGroupsin__libc_LogInit[Ex]is NULL which is perfectly legal), an attempt to write out anything into the log file will result in a truncated log header:and a crash in LIBC:
The crash happens because when LIBC writes enabled log groups to the header, it doesn't check if
pGroupsis NULL before accessing it and hence the crash.This is a regression of a9eb83452cb2b814b77cdac82c985f46a1188fb3.
The problem is rather critical as it completely breaks LIBCx assertion logging and will even result into shadowing a proper EXCEPTQ report (related to the LIBCx assertion) with LIBC own (shown above), see https://github.com/bitwiseworks/libcx/issues/98. Needs an urgent fix.