[reversing] Go 바이너리 분석

ctftime.org에서 Go 바이너리를 발견해 Go 공부를 시작했다.
C언어로 개발하던 짬이 있어선지 언어 습득은 2시간 정도 걸렸고, 그렇게 습득한 언어로 여러가지 코드를 짜보며 어셈으론 어떻게 나오는지 확인해봤다.

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1. 함수 호출

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함수를 호출할 때 인자를 어떻게 전달하는지 알아보기 위해 인자를 10개로 갖는 함수를 하나 선언하고, 어셈블리어로 확인해봤다.

C언어에서는 rdi, rsi, rdx, rcx ... 순으로 인자가 전달됐는데, Go에서는 인자가 rax, rbx, rcx, rdi, rsi, r8, r9, r10, r11 .... 이런 식으로 전달된다.

가변 인자는 C언어와 비슷하게 스택에 쌓고 가변 인자의 시작 주소와 개수를 전달한다.
가변 인자와 관련해 발견한 특징 중 하나는 인자 하나당 16바이트를 사용한다는 것이고, 앞의 8바이트는 8, 16 등.. 특정한 값을 가리키는 포인터(인자의 크기로 추정된다.)가 오고, 뒤의 8바이트는 인자를 가리키는 포인터를 전달한다.

이렇게 함수가 호출돼서 다른 함수로 넘어가면, 함수 프롤로그에선 rsp값을 검사한다.
아마 스택을 쌓을 공간이 더 있는지 확인하는듯 하다.

이렇게 rsp 검사가 끝나면 rsp와 rbp값을 바꿔 현재 함수의 스택프레임을 만들어야 한다.
과정은 다음과 같다.

rsp에서 필요한 크기를 빼고, rbp를 새로운 스택프레임의 바닥에 저장한 뒤, 새로운 스택프레임의 바닥으로 정한다.
(C언어와 크게 다르지 않은 것 같다.)

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2. main_main 찾기

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(디버깅은 IDA Remote Debugging을 기준으로 설명)

Go 바이너리가 strip 되어 있으면 main_main을 찾아야 하는데, 생각처럼 간단한 일이 아닐 수 있다.
내가 main_main을 찾는 방법은 F9를 눌러 SIGURG가 발생할 때를 찾고 이후에 F8을 한 번씩 눌러보며 메인 루틴이 발생하는 곳까지 디버깅해보는 것이다.
왜 그런지는 모르겠지만 main_main 함수를 호출하기 전에 여러 번의 SIGURG가 발생한다.

다음은 read syscall이 발생할 때까지의 strace 결과값이고, read syscall이 발생하기 바로 전에 SIGURG가 발생하는 걸 볼 수 있다.

execve("./prob", ["./prob"], 0x7ffcd8ec6a50 /* 26 vars */) = 0
arch_prctl(ARCH_SET_FS, 0x5403d0)       = 0
sched_getaffinity(0, 8192, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19]) = 32
openat(AT_FDCWD, "/sys/kernel/mm/transparent_hugepage/hpage_pmd_size", O_RDONLY) = 3
read(3, "2097152\n", 20)                = 8
close(3)                                = 0
mmap(NULL, 262144, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee73b79000
mmap(NULL, 131072, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee73b59000
mmap(NULL, 1048576, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee73a59000
mmap(NULL, 8388608, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee73259000
mmap(NULL, 67108864, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee6f259000
mmap(NULL, 536870912, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4f259000
mmap(0xc000000000, 67108864, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc000000000
mmap(NULL, 33554432, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4d259000
mmap(NULL, 2165776, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4d048000
mmap(0xc000000000, 4194304, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xc000000000
mmap(0x7fee73b59000, 131072, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fee73b59000
mmap(0x7fee73ad9000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fee73ad9000
mmap(0x7fee7365f000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fee7365f000
mmap(0x7fee71289000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fee71289000
mmap(0x7fee5f3d9000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fee5f3d9000
mmap(NULL, 1048576, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4cf48000
mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4cf38000
mmap(NULL, 65536, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fee4cf28000
rt_sigprocmask(SIG_SETMASK, NULL, [], 8) = 0
sigaltstack(NULL, {ss_sp=NULL, ss_flags=SS_DISABLE, ss_size=0}) = 0
sigaltstack({ss_sp=0xc000004000, ss_flags=0, ss_size=32768}, NULL) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
gettid()                                = 23466
rt_sigaction(SIGHUP, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGHUP, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGINT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGINT, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGQUIT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGQUIT, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGILL, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGILL, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGTRAP, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTRAP, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGABRT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGABRT, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGBUS, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGBUS, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGFPE, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGFPE, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGUSR1, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGUSR1, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGSEGV, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGSEGV, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGUSR2, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGUSR2, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGPIPE, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGPIPE, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGALRM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGALRM, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGTERM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGTERM, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGSTKFLT, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGSTKFLT, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGCHLD, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGCHLD, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGURG, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGURG, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGXCPU, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGXCPU, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGXFSZ, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGXFSZ, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGVTALRM, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGVTALRM, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGPROF, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGPROF, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGWINCH, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGWINCH, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGIO, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGIO, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGPWR, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGPWR, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGSYS, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGSYS, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRTMIN, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_1, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_1, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_2, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_3, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_3, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_4, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_4, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_5, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_5, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_6, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_6, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_7, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_7, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_8, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_8, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_9, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_9, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_10, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_10, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_11, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_11, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_12, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_12, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_13, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_13, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_14, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_14, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_15, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_15, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_16, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_16, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_17, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_17, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_18, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_18, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_19, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_19, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_20, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_20, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_21, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_21, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_22, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_22, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_23, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_23, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_24, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_24, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_25, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_25, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_26, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_26, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_27, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_27, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_28, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_28, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_29, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_29, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_30, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_30, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_31, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_31, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigaction(SIGRT_32, NULL, {sa_handler=SIG_DFL, sa_mask=[], sa_flags=0}, 8) = 0
rt_sigaction(SIGRT_32, {sa_handler=0x45cb60, sa_mask=~[], sa_flags=SA_RESTORER|SA_ONSTACK|SA_RESTART|SA_SIGINFO, sa_restorer=0x45cca0}, NULL, 8) = 0
rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0
clone(child_stack=0xc000074000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS, tls=0xc000064090) = 23467
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0
clone(child_stack=0xc000076000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS, tls=0xc000064490) = 23468
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
--- SIGURG {si_signo=SIGURG, si_code=SI_TKILL, si_pid=23466, si_uid=1000} ---
rt_sigreturn({mask=[]})                 = 0
--- SIGURG {si_signo=SIGURG, si_code=SI_TKILL, si_pid=23466, si_uid=1000} ---
rt_sigreturn({mask=[]})                 = 5209644
futex(0xc000064548, FUTEX_WAKE_PRIVATE, 1) = 1
rt_sigprocmask(SIG_SETMASK, ~[], [], 8) = 0
clone(child_stack=0xc000070000, flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS, tls=0xc000064890) = 23470
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
fcntl(0, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
futex(0xc000064948, FUTEX_WAKE_PRIVATE, 1) = 1
fcntl(1, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
fcntl(2, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
write(1, "input : ", 8input : )                 = 8
read(0,

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3. 동적 할당

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makeslice : 배열 할당

growslice : 배열에 요소 추가

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나머지는 대부분 그냥 어셈블리어 분석이기 때문에 흐름을 잘 따라가다 보면 분석할 수 있다.