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Merged
oriansj merged 2 commits into from
Dec 14, 2023
Merged

Add syscalls needed for a simple sandbox #47

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661cdb3
Add syscalls needed for a simple sandbox
MaxHearnden Nov 30, 2023
6f8fda3
ulong -> unsigned long
MaxHearnden Nov 30, 2023
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7 changes: 7 additions & 0 deletions aarch64/aarch64_defs.M1
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Original file line number Diff line number Diff line change
Expand Up @@ -117,6 +117,8 @@ DEFINE SUB_X0_X0_X1 000001cb
DEFINE SUB_X0_8 002000d1
DEFINE SUB_X0_16 004000d1
DEFINE SUB_X0_24 006000d1
DEFINE SUB_X0_32 008000d1
DEFINE SUB_X0_40 00A000d1
DEFINE MSUB_X0_X0_X2_X1 0084029b

DEFINE MUL_X0_X1_X0 207c009b
Expand Down Expand Up @@ -160,4 +162,9 @@ DEFINE SET_X8_TO_SYS_WAIT4 882080d2
DEFINE SET_X8_TO_SYS_WRITE 080880d2
DEFINE SET_X8_TO_SYS_UNLINK 488080d2
DEFINE SET_X8_TO_SYS_UMASK c81480d2
DEFINE SET_X8_TO_SYS_UNSHARE 280c80d2
DEFINE SET_X8_TO_SYS_GETEUID e81580d2
DEFINE SET_X8_TO_SYS_GETEGID 081680d2
DEFINE SET_X8_TO_SYS_CHROOT 680680d2
DEFINE SET_X8_TO_SYS_MOUNT 080580d2
DEFINE SYSCALL 010000d4
47 changes: 47 additions & 0 deletions aarch64/linux/unistd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -197,4 +197,51 @@ int uname(struct utsname* unameData)
"SYSCALL");
}

int unshare(int flags) {
asm (
"SET_X0_FROM_BP" "SUB_X0_8" "DEREF_X0"
"SET_X8_TO_SYS_UNSHARE"
"SYSCALL"
);
}

int geteuid() {
asm (
"SET_X8_TO_SYS_GETEUID"
"SYSCALL"
);
}

int getegid() {
asm (
"SET_X8_TO_SYS_GETEGID"
"SYSCALL"
);
}

int chroot(char const *path) {
asm (
"SET_X0_FROM_BP" "SUB_X0_8" "DEREF_X0"
"SET_X8_TO_SYS_CHROOT"
"SYSCALL"
);
}

int mount(char const *source, char const *target, char const *filesystemtype,
ulong mountflags, void const *data) {
asm (
"SET_X0_FROM_BP" "SUB_X0_40" "DEREF_X0"
"SET_X4_FROM_X0"
"SET_X0_FROM_BP" "SUB_X0_32" "DEREF_X0"
"SET_X3_FROM_X0"
"SET_X0_FROM_BP" "SUB_X0_24" "DEREF_X0"
"SET_X2_FROM_X0"
"SET_X0_FROM_BP" "SUB_X0_16" "DEREF_X0"
"SET_X1_FROM_X0"
"SET_X0_FROM_BP" "SUB_X0_8" "DEREF_X0"
"SET_X8_TO_SYS_MOUNT"
"SYSCALL"
);
}

#endif
3 changes: 3 additions & 0 deletions amd64/amd64_defs.M1
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,9 @@ DEFINE lea_rdx,[rsp+DWORD] 488D9424
DEFINE lea_rdx,[rbp+DWORD] 488D95
DEFINE lea_rsi,[rsp+DWORD] 488DB424
DEFINE lea_r8,[rbp+DWORD] 4C8D85
DEFINE lea_r8,[rsp+DWORD] 4C8D8424
DEFINE lea_r9,[rbp+DWORD] 4C8D8D
DEFINE lea_r10,[rsp+DWORD] 4C8D9424
DEFINE mov_rax, 48C7C0
DEFINE mov_rbx, 48C7C3
DEFINE mov_rdi, 48C7C7
Expand Down Expand Up @@ -81,6 +83,7 @@ DEFINE mov_rbp,[rip+DWORD] 488B2D
DEFINE mov_rsp,[rip+DWORD] 488B25
DEFINE mov_r8,[r8] 4D8B00
DEFINE mov_r9,[r9] 4D8B09
DEFINE mov_r10,[r10] 4D8B12
DEFINE movzx_rax,al 480FB6C0
DEFINE movsxd_rax,eax 4863C0
DEFINE movsx_rax,BYTE_PTR_[rax] 480FBE00
Expand Down
53 changes: 53 additions & 0 deletions amd64/linux/unistd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -199,4 +199,57 @@ int uname(struct utsname* unameData)
"mov_rax, %63"
"syscall");
}

int unshare(int flags) {
asm (
"lea_rdi,[rsp+DWORD] %8"
"mov_rdi,[rdi]"
"mov_rax, %272"
"syscall"
);
}

int geteuid() {
asm (
"mov_rax, %107"
"syscall"
);
}

int getegid() {
asm (
"mov_rax, %108"
"syscall"
);
}

int mount(
char *source, char *target, char *filesystemtype,
ulong mountflags, void *data
) {
asm (
"lea_rdi,[rsp+DWORD] %40"
"mov_rdi,[rdi]"
"lea_rsi,[rsp+DWORD] %32"
"mov_rsi,[rsi]"
"lea_rdx,[rsp+DWORD] %24"
"mov_rdx,[rdx]"
"lea_r10,[rsp+DWORD] %16"
"mov_r10,[r10]"
"lea_r8,[rsp+DWORD] %8"
"mov_r8,[r8]"
"mov_rax, %165"
"syscall"
);
}

int chroot(char *path) {
asm (
"lea_rdi,[rsp+DWORD] %8"
"mov_rdi,[rdi]"
"mov_rax, %161"
"syscall"
);
}

#endif
48 changes: 48 additions & 0 deletions armv7l/linux/unistd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -191,4 +191,52 @@ int uname(struct utsname* unameData)
"!0 R0 LOAD32 R0 MEMORY"
"SYSCALL_ALWAYS");
}

int unshare(int flags) {
asm("!4 R0 SUB R12 ARITH_ALWAYS"
"!0 R0 LOAD32 R0 MEMORY"
"!337 R7 LOADI8_ALWAYS"
"SYSCALL_ALWAYS");
}

int geteuid() {
asm(
"!201 R7 LOADI8_ALWAYS"
"SYSCALL_ALWAYS"
);
}

int getegid() {
asm (
"!202 R7 LOADI8_ALWAYS"
"SYSCALL_ALWAYS"
);
}

int chroot(char const *path) {
asm (
"!4 R0 SUB R12 ARITH_ALWAYS"
"!61 R7 LOADI8_ALWAYS"
"SYSCALL_ALWAYS"
);
}

int mount(char const *source, char const *target, char const *filesystemtype,
ulong mountflags, void const *data) {
asm (
"!4 R0 SUB R12 ARITH_ALWAYS"
"!0 R0 LOAD32 R0 MEMORY"
"!8 R1 SUB R12 ARITH_ALWAYS"
"!0 R1 LOAD32 R1 MEMORY"
"!12 R2 SUB R12 ARITH_ALWAYS"
"!0 R2 LOAD32 R2 MEMORY"
"!16 R3 SUB R12 ARITH_ALWAYS"
"!0 R3 LOAD32 R3 MEMORY"
"!20 R4 SUB R12 ARITH_ALWAYS"
"!0 R4 LOAD32 R4 MEMORY"
"!31 R7 LOADI8_ALWAYS"
"SYSCALL_ALWAYS"
);
}

#endif
45 changes: 45 additions & 0 deletions riscv32/linux/unistd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -235,4 +235,49 @@ int uname(struct utsname* unameData)
"ecall");
}

int unshare(int flags) {
asm (
"rd_a0 rs1_fp !-4 lw"
"rd_a7 !97 addi"
"ecall"
);
}

int geteuid() {
asm (
"rd_a7 !175 addi"
"ecall"
);
}

int getegid() {
asm (
"rd_a7 !177 addi"
"ecall"
);
}

int mount (
char *source, char *target, char *filesystemtype,
ulong mountflags, void *data
) {
asm (
"rd_a0 rs1_fp !-4 lw"
"rd_a1 rs1_fp !-8 lw"
"rd_a2 rs1_fp !-12 lw"
"rd_a3 rs1_fp !-16 lw"
"rd_a4 rs1_fp !-20 lw"
"rd_a7 !40 addi"
"ecall"
);
}

int chroot(char *path) {
asm (
"rd_a0 rs1_fp !-4 lw"
"rd_a7 !51 addi"
"ecall"
);
}

#endif
45 changes: 45 additions & 0 deletions riscv64/linux/unistd.c
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Original file line number Diff line number Diff line change
Expand Up @@ -179,4 +179,49 @@ int uname(struct utsname* unameData)
"ecall");
}

int unshare(int flags) {
asm (
"rd_a0 rs1_fp !-8 ld"
"rd_a7 !97 addi"
"ecall"
);
}

int geteuid() {
asm (
"rd_a7 !175 addi"
"ecall"
);
}

int getegid() {
asm (
"rd_a7 !177 addi"
"ecall"
);
}

int mount (
char *source, char *target, char *filesystemtype,
ulong mountflags, void *data
) {
asm (
"rd_a0 rs1_fp !-8 ld"
"rd_a1 rs1_fp !-16 ld"
"rd_a2 rs1_fp !-24 ld"
"rd_a3 rs1_fp !-32 ld"
"rd_a4 rs1_fp !-40 ld"
"rd_a7 !40 addi"
"ecall"
);
}

int chroot(char *path) {
asm (
"rd_a0 rs1_fp !-8 ld"
"rd_a7 !51 addi"
"ecall"
);
}

#endif
29 changes: 27 additions & 2 deletions uefi/uefi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -59,6 +59,7 @@ char** _argv;
char** _envp;

char* _cwd;
char* _root;

struct efi_simple_text_output_protocol
{
Expand Down Expand Up @@ -491,8 +492,12 @@ char* _relative_path_to_absolute(char* narrow_string)
char* absolute_path = calloc(__PATH_MAX, 1);
if(narrow_string[0] != '/' && narrow_string[0] != '\\')
{
strcpy(absolute_path, _cwd);
strcat(absolute_path, _cwd);
}
else
{
strcat(absolute_path, _root);
}
strcat(absolute_path, narrow_string);

return absolute_path;
Expand Down Expand Up @@ -704,6 +709,7 @@ char* strchr(char const* str, int ch);
void _setup_current_working_directory(char** envp)
{
_cwd = calloc(__PATH_MAX, 1);
_root = calloc(__PATH_MAX, 1);

unsigned i = 0;
unsigned j;
Expand All @@ -719,7 +725,26 @@ void _setup_current_working_directory(char** envp)
j += 1;
}
envp[i][j] = 0;
if(strcmp(envp[i], "cwd") == 0)
if(strcmp(envp[i], "root") == 0)
{
value = envp[i] + j + 1;
match = strchr(value, ':'); /* strip uefi device, e.g. fs0: */
if(match != NULL)
{
value = match + 1;
}
strcpy(_root, value);
k = 0;
while(_root[k] != '\0')
{
if(_root[k] == '\\')
{
_root[k] = '/';
}
k += 1;
}
}
else if(strcmp(envp[i], "cwd") == 0)
{
value = envp[i] + j + 1;
match = strchr(value, ':'); /* strip uefi device, e.g. fs0: */
Expand Down
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