segmentfault

[yangboyd]

kernel: traps: ls[6598] general protection ip:7fc701007c85 sp:7ffc7f0f5248 error:0 in libc-2.17.so[7fc700f1a000+1b6000]

(gdb) bt
#0 0x00007f7b40633c85 in tcgetattr () from /lib64/libc.so.6
#1 0x00007f7b406301fc in isatty () from /lib64/libc.so.6
#2 0x0000000000402a8f in ?? ()
#3 0x00007f7b4118a8f0 in __frame_dummy_init_array_entry () from ./libzpoline.so
#4 0x00007f7b40f680fe in asm_syscall_hook () from ./libzpoline.so
#5 0x0000000000000000 in ?? ()
(gdb) f 3
#3 0x00007f7b4118a8f0 in __frame_dummy_init_array_entry () from ./libzpoline.so
(gdb) disas
Dump of assembler code for function __frame_dummy_init_array_entry:
0x00007f7b4118a8e8: (bad)
0x00007f7b4118a8e9: jg 0x7f7b4118a8e1
0x00007f7b4118a8eb: rex jnp 0x7f7b4118a96d <rexes.11457+77>
0x00007f7b4118a8ee: add %al,(%rax)
=> 0x00007f7b4118a8f0: mov $0x7b,%al
0x00007f7b4118a8f2: testb $0x7f,0x7b(%rax)
0x00007f7b4118a8f6: add %al,(%rax)
End of assembler dump.
(gdb) f 4
#4 0x00007f7b40f680fe in asm_syscall_hook () from ./libzpoline.so
(gdb) disas
Dump of assembler code for function asm_syscall_hook:
0x00007f7b40f680da <+0>: pop %rax
0x00007f7b40f680db <+1>: cmp $0xf,%rax
0x00007f7b40f680df <+5>: je 0x7f7b40f68110 <do_rt_sigreturn>
0x00007f7b40f680e1 <+7>: push %rbp
0x00007f7b40f680e2 <+8>: mov %rsp,%rbp
0x00007f7b40f680e5 <+11>: and $0xfffffffffffffff0,%rsp
0x00007f7b40f680e9 <+15>: push %r11
0x00007f7b40f680eb <+17>: push %r9
0x00007f7b40f680ed <+19>: push %r8
0x00007f7b40f680ef <+21>: push %rdi
0x00007f7b40f680f0 <+22>: push %rsi
0x00007f7b40f680f1 <+23>: push %rdx
0x00007f7b40f680f2 <+24>: push %rcx
0x00007f7b40f680f3 <+25>: pushq 0x8(%rbp)
0x00007f7b40f680f6 <+28>: push %rax
0x00007f7b40f680f7 <+29>: push %r10
0x00007f7b40f680f9 <+31>: callq 0x7f7b40f67620 syscall_hook@plt
=> 0x00007f7b40f680fe <+36>: pop %r10
0x00007f7b40f68100 <+38>: add $0x10,%rsp
0x00007f7b40f68104 <+42>: pop %rcx
0x00007f7b40f68105 <+43>: pop %rdx
0x00007f7b40f68106 <+44>: pop %rsi
0x00007f7b40f68107 <+45>: pop %rdi
0x00007f7b40f68108 <+46>: pop %r8
0x00007f7b40f6810a <+48>: pop %r9
0x00007f7b40f6810c <+50>: pop %r11
0x00007f7b40f6810e <+52>: leaveq
0x00007f7b40f6810f <+53>: retq
End of assembler dump.
(gdb) info registers
rax 0x0 0
rbx 0x0 0
rcx 0x8a3b 35387
rdx 0x500 1280
rsi 0x10004157f1c03 281492517231619
rdi 0x500000500 21474837760
rbp 0x2 0x2
rsp 0x7ffd658780e0 0x7ffd658780e0
r8 0x8a3b000000bf 151986007703743
r9 0x10004157f1c0300 72062084411294464
r10 0x0 0
r11 0x170f12001a131100 1661566579169759488
r12 0x7ffd65878248 140726306832968
r13 0x7ffd65878240 140726306832960
r14 0x0 0
r15 0x0 0
rip 0x7f7b40f680fe 0x7f7b40f680fe <asm_syscall_hook+36>
eflags 0x10246 [ PF ZF IF RF ]
cs 0x33 51
ss 0x2b 43
ds 0x0 0
es 0x0 0
fs 0x0 0
gs 0x0 0

[yasukata]

Thank you for your report.

Could you give me a bit more information so that I can reproduce this error?

Particularly, the following information will be helpful.

• the command, you executed
• OS distribution (e.g., Ubuntu 22.04)
• CPU (e.g., Intel Xeon E5-2640)

[yangboyd]

LIBZPHOOK=./apps/basic/libzphook_basic.so LD_PRELOAD=./libzpoline.so ls
CentOS 7
x86_64 vm
On centos7 the code cannot be compiled, so I use /opt/rh/devtoolset-8/root/usr/bin/gcc to compile, install via yum install devtoolset-8-binutils-devel

LIBZPHOOK=./apps/basic/libzphook_basic.so LD_PRELOAD=./libzpoline.so /opt/rh/devtoolset-8/root/usr/bin/gcc
Initializing zpoline ...
-- Setting up trampoline code
-- Rewriting the code
Loading hook library ...
-- load ./apps/basic/libzphook_basic.so
-- call hook init
output from __hook_init: we can do some init work here
output from hook_function: syscall number 1
Start main program
output from hook_function: syscall number 12
output from hook_function: syscall number 12
output from hook_function: syscall number 12
output from hook_function: syscall number 2
output from hook_function: syscall number 5
output from hook_function: syscall number 9
output from hook_function: syscall number 3
output from hook_function: syscall number 2
output from hook_function: syscall number 5
output from hook_function: syscall number 9
output from hook_function: syscall number 0
output from hook_function: syscall number 0
output from hook_function: syscall number 3
output from hook_function: syscall number 11
output from hook_function: syscall number 2
output from hook_function: syscall number 2
output from hook_function: syscall number 2
output from hook_function: syscall number 2
output from hook_function: syscall number 2
output from hook_function: syscall number 2
output from hook_function: syscall number 21
output from hook_function: syscall number 16
Segmentation fault
[]# uname -a
Linux 3.10.0-1062.12.1.el7.x86_64 #1 SMP Tue Feb 4 23:02:59 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

[yasukata]

I could reproduce the error.

I will look into this, and get back to you once I figure out the problem.

Thank you for reporting the issue.