Initial working version of lace

Signed-off-by: Malfurious <m@lfurio.us>

2 files changed, 149 insertions, 0 deletions

diff --git a/lace_x86.asm b/lace_x86.asm
new file mode 100644
index 0000000..f1076ea
--- /dev/null
+++ b/lace_x86.asm
@@ -0,0 +1,149 @@
+BITS 32
+
+    org     0x00010000      ; Memory load location
+
+    ;                         ELF HEADER CONTENT                                PROGRAM HEADER TBL ENTRY CONTENT
+    ; ------------------------------------------------------------------------------------------------------------------
+    db      0x7f, "ELF"     ; magic number: 7f454c46
+    db      0x01            ; class:        1 (32-bit)                          type:       1 (Loadable segment)
+    db      0x00            ; data:         0 (invalid)*                        |
+    db      0x00            ; version:      0 (invalid)*                        |
+    db      0x00            ; abi:          0 (System V)                        |
+    db      0x00            ; abi version:  0                                   offset:     0 (File offset)
+    db      0x00            ; padding                                           |
+    db      0x00            ; |                                                 |
+    db      0x00            ; |                                                 |
+    dd      $$              ; |                                                 vaddr:      $$ (File memory location)
+    db      0x02            ; type:         2 (Executable)                      paddr:      0x00030002 *
+    db      0x00            ; |                                                 |
+    db      0x03            ; machine:      3 (Intel i386 x86)                  |
+    db      0x00            ; |                                                 |
+    dd      _start          ; version:      _start (invalid)*                   filesz:     _start (too large)***
+    dd      _start          ; entry:        _start (Program entry point)        memsz:      _start ***
+    db      0x04            ; phoff:        4 (File offset)                     flags:      4 (READ) ***
+    db      0x00            ; |                                                 |
+    db      0x00            ; |                                                 |
+    db      0x00            ; |                                                 |
+    db      0x00            ; shoff:        0 (File offset)**                   align:      0 (No alignment constraints)
+    db      0x00            ; |                                                 |
+    db      0x00            ; |                                                 |
+    db      0x00            ; |                                                 |
+    db      0x00            ; flags:        0
+    db      0x00            ; |
+    db      0x00            ; |
+    db      0x00            ; |
+    db      0x34            ; ehsize:       52
+    db      0x00            ; |
+    db      0x20            ; phentsize:    32
+    db      0x00            ; |
+    db      0x01            ; phnum:        1 (.text)
+    db      0x00            ; |
+   ;db      0x00            ; shentsize:    0**         [ Cut these out to overlap with program code ]
+   ;db      0x00            ; |
+   ;db      0x00            ; shnum:        0**
+   ;db      0x00            ; |
+   ;db      0x00            ; shstrndx:     0**
+   ;db      0x00            ; |
+
+    ; For space savings, the above constructs the ELF metadata for this program
+    ; without invoking an external linker.  The ELF header and the program
+    ; header entry completely overlap each other.  Some concessions were made to
+    ; allow this to be possible.  See the asterisks above and explainations
+    ; below for details.
+    ;
+    ; *   Invalid values are present to leverage overloading fields that go
+    ;     unchecked by the loader at runtime.  Such values are likely being set
+    ;     to what is required by the other data structure.
+    ;
+    ; **  Section headers are not utilized by this program, so no relevant
+    ;     header fields are utilized.  As with (*) fields, these too go
+    ;     unchecked by the loader.
+    ;
+    ; *** phoff must be == 4 in this arrangement, therefore program header flags
+    ;     just match it.  This is fine, as apparently execute is implied in this
+    ;     case.  However, since the writable bit is not set, we can not set
+    ;     memsz larger than filesz (the loader is not able to 'write' the extra
+    ;     initializing zero bytes).  Therefore, both fields are set to the value
+    ;     of the program entry point, so that the entry point field from ELF
+    ;     (which coinsides) can be set properly.  The fact that filesz will be
+    ;     larger than that of the actual output file is of no consequence.
+
+_start:
+    mov     ebp, esp
+    sub     esp, 16     ; alloc struct sockaddr_in
+
+    xor     edx, edx    ; open(argv[1], 0, 0)
+    xor     ecx, ecx
+    mov     ebx, [ebp+8]
+    xor     eax, eax
+    mov      al, 5
+    int     0x80
+
+    cmp     eax, 0      ; if fail, exit(1)
+    mov      bl, 1
+    jle     exit
+
+    mov      dl, 16     ; read(fd, sockaddr_in, sizeof(sockaddr_in))
+    mov     ecx, esp
+    mov     ebx, eax
+    mov      al, 3
+    int     0x80
+
+    cmp     eax, 16     ; if fail, exit(2)
+    mov      bl, 2
+    jne     exit
+
+    push    0           ; socket(AF_INET, SOCK_STREAM, 0)
+    push    1
+    push    2
+    mov     ecx, esp
+    mov      bl, 1
+    mov      al, 0x66
+    int     0x80
+
+    push    16          ; connect(sock, sockaddr_in, sizeof(sockaddr_in))
+    lea     ecx, [esp+16]
+    push    ecx
+    push    eax
+    mov     ecx, esp
+    mov      bl, 3
+    mov      al, 0x66
+    int     0x80
+
+    cmp     eax, 0      ; if fail, exit(3)
+    mov      bl, 3
+    jne     exit
+
+    pop     edi         ; recover socket fd
+    sub     esp, 0xff   ; alloc data buffer
+
+    xor     esi, esi    ; pipe(sock, stdin)
+    call    pipe
+
+    xchg    edi, esi    ; pipe(stdin, sock)
+    call    pipe
+
+    xor     ebx, ebx    ; exit(0)
+    jmp     exit
+
+pipe:
+    mov      dl, 0xff   ; read(src, buff, sizeof(buff))
+    lea     ecx, [esp+4]
+    mov     ebx, esi
+    mov      al, 3
+    int     0x80
+
+    cmp     eax, 0      ; if finished, return
+    jg      pipe_cont
+    ret
+
+pipe_cont:
+    mov     edx, eax    ; write(dst, buff, nb)
+    mov     ebx, edi
+    mov      al, 4
+    int     0x80
+    jmp     pipe        ; loop
+
+exit:
+    mov      al, 1
+    int     0x80
diff --git a/sockaddr_127-0-0-1_1337.bin b/sockaddr_127-0-0-1_1337.bin
new file mode 100644
index 0000000..8078d06
--- /dev/null
+++ b/sockaddr_127-0-0-1_1337.bin