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libc cleanup

This commit is contained in:
'mr software' 2023-11-28 11:34:13 -08:00
parent 2bc387b2cf
commit 0e433c11a2
2 changed files with 29 additions and 91 deletions
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54
main.c
View File

@ -11,10 +11,8 @@
#define SYSCT_FBSD 588 #define SYSCT_FBSD 588
extern void trap(gregset_t);
extern void cat(int fd, long sz); extern void cat(int fd, long sz);
extern uint32_t trapsz; uint8_t sel = SYSCALL_DISPATCH_FILTER_ALLOW;
extern uint8_t sel;
uint16_t scmap[SYSCT_FBSD] = { uint16_t scmap[SYSCT_FBSD] = {
-1, // SYS_syscall needs args shifted -1, // SYS_syscall needs args shifted
@ -30,11 +28,31 @@ uint16_t scmap[SYSCT_FBSD] = {
SYS_unlink, SYS_unlink,
-1, // [obsolete] execv -1, // [obsolete] execv
SYS_chdir, SYS_chdir,
SYS_fchdir SYS_fchdir,
-1, // [freebsd11] mknod
SYS_chmod,
SYS_chown,
-1, // break (no manual)
-1, // [freebsd4] getfsstat
-1, // [old] lseek
SYS_getpid,
}; };
void ftrp(int n, siginfo_t* s, ucontext_t* c) { // TODO also create trampoline for freebsd native signals
void systrap(int n, siginfo_t* s, ucontext_t* c) {
sel = SYSCALL_DISPATCH_FILTER_ALLOW; sel = SYSCALL_DISPATCH_FILTER_ALLOW;
if(s->si_code != /* SYS_USER_DISPATCH - value from <asm-generic/siginfo.h> */ 2) {
// TODO chain old syscall handler
} else if(s->si_syscall > SYSCT_FBSD-1) {
// TODO fail - check how freebsd does this, esp. with nosys entries
} else if(scmap[s->si_syscall] == -1) {
switch(s->si_syscall) {
default:
abort();
break;
}
}
// TODO find max arg ct. and check stack if needed
c->uc_mcontext.gregs[13] = syscall( c->uc_mcontext.gregs[13] = syscall(
scmap[s->si_syscall], scmap[s->si_syscall],
c->uc_mcontext.gregs[8], c->uc_mcontext.gregs[8],
@ -42,9 +60,7 @@ void ftrp(int n, siginfo_t* s, ucontext_t* c) {
c->uc_mcontext.gregs[12] c->uc_mcontext.gregs[12]
); );
//for(int i = 0; i < 23; i++) printf("%i: %lX\n", i, c->uc_mcontext.gregs[i]); //for(int i = 0; i < 23; i++) printf("%i: %lX\n", i, c->uc_mcontext.gregs[i]);
//printf("%u\n", s->si_arch);
sel = SYSCALL_DISPATCH_FILTER_BLOCK; sel = SYSCALL_DISPATCH_FILTER_BLOCK;
//trap(c->uc_mcontext.gregs);
} }
typedef struct { typedef struct {
@ -134,12 +150,12 @@ int main(int argc, char** argv) {
struct sigaction a, oa; struct sigaction a, oa;
sigemptyset(&a.sa_mask); sigemptyset(&a.sa_mask);
a.sa_flags = SA_SIGINFO; a.sa_flags = SA_SIGINFO;
a.sa_sigaction = ftrp; a.sa_sigaction = (void(*)(int, siginfo_t*, void*))systrap;
sigaction(SIGSYS, &a, &oa);
sel = SYSCALL_DISPATCH_FILTER_ALLOW;
int nm; int nm;
char** smaps = getmaps(&nm); char** smaps = getmaps(&nm);
// TODO RW to only call stomap if strstr libc - saves memory and cycles
map maps[nm-1]; map maps[nm-1];
for(int i = 0; i < nm-1; i++) { for(int i = 0; i < nm-1; i++) {
stomap(smaps[i], maps + i); stomap(smaps[i], maps + i);
@ -160,29 +176,17 @@ int main(int argc, char** argv) {
".X"[(maps[i].rwx >> 0) & 1] ".X"[(maps[i].rwx >> 0) & 1]
); );
*/ */
if( ( if(strstr(maps[i].name, "libc") && (maps[i].rwx & 1)) prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, maps[i].start, maps[i].len, &sel);
strstr(maps[i].name, "libc")
//||strstr(maps[i].name, "ld-linux") ||
//strstr(maps[i].name, "fl") ||
//!strcmp(maps[i].name, "[vdso]") ||
//!strcmp(maps[i].name, "[vsyscall]")
) && (maps[i].rwx & 1)
) {
prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, maps[i].start, maps[i].len, &sel);
// printf("enable sud bypass\n");
}
//printf("\n");
} }
for(int i = 0; i < nm; i++) free(smaps[i]); for(int i = 0; i < nm; i++) free(smaps[i]);
free(smaps); free(smaps);
// END RW
if(argc < 2) return printf("no file provided\n"); if(argc < 2) return printf("no file provided\n");
int fd = open(argv[1], O_RDONLY); int fd = open(argv[1], O_RDONLY);
struct stat s; struct stat s;
fstat(fd, &s); fstat(fd, &s);
//printf("start cat() with freebsd syscalls\n"); sigaction(SIGSYS, &a, &oa);
//prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, trap, trapsz, &sel);
//write(1, "fghgfgfg\n", 9);
sel = SYSCALL_DISPATCH_FILTER_BLOCK; sel = SYSCALL_DISPATCH_FILTER_BLOCK;
cat(fd, s.st_size); cat(fd, s.st_size);
} }

66
th.s
View File

@ -1,79 +1,13 @@
bits 64 bits 64
default rel default rel
global trap
global trapsz
global cat global cat
global sel
extern scmap
section .data section .data
sel: db 1
trapsz: dd cat-trap;
buf: db 0 buf: db 0
section .text section .text
trap:
;mov rax, 60
;syscall
push r8
push r9
push r10
push r11
push r12
push r13
push r14
push r15
push rsi
push rbp
push rbx
push rdx
push rcx
mov r8, [rdi]
mov r9, [rdi+8]
mov r10, [rdi+16]
mov r11, [rdi+24]
mov r12, [rdi+32]
mov r13, [rdi+40]
mov r14, [rdi+48]
mov r15, [rdi+56]
mov rsi, [rdi+72]
mov rbp, [rdi+80]
mov rbx, [rdi+88]
mov rdx, [rdi+96]
mov rax, [rdi+104]
mov rcx, [rdi+112]
mov rdi, [rdi+64]
syscall
pop rcx
pop rdx
pop rbx
pop rbp
pop rsi
pop r15
pop r14
pop r13
pop r12
pop r11
pop r10
pop r9
pop r8
ret
push rbx
;mov ax, word [rel scmap + 2*eax]
lea rbx, [scmap]
lea rax, [rbx + 2*rax]
movzx eax, ax
pop rbx
ret
cat: cat:
push r12 push r12
push rbx push rbx