initial

3 files changed, 180 insertions, 0 deletions

diff --git a/other/prefix/prefix b/other/prefix/prefix
new file mode 100644
index 0000000..bebdddb
--- /dev/null
+++ b/other/prefix/prefix
diff --git a/other/prefix/prefix.asm b/other/prefix/prefix.asm
new file mode 100644
index 0000000..b77aade
--- /dev/null
+++ b/other/prefix/prefix.asm
@@ -0,0 +1,103 @@
+
+        BITS 32
+
+        org     0x08048000
+
+ehdr:                                   ; Elf32_Ehdr
+        db      0x7F, "ELF", 1, 1, 1    ;  e_ident
+        times 9 db      0
+        dw      2                       ;  e_type
+        dw      3                       ;  e_machine
+        dd      1                       ;  e_version
+        dd      _start                  ;  e_entry
+        dd      phdr - $$               ;  e_phoff
+        dd      0                       ;  e_shoff
+        dd      0                       ;  e_flags
+        dw      ehdrsize                ;  e_ehsize
+        dw      phdrsize                ;  e_phentsize
+        dw      1                       ;  e_phnum
+        dw      0                       ;  e_shentsize
+        dw      0                       ;  e_shnum
+        dw      0                       ;  e_shstrndx
+
+ehdrsize        equ     ($ - ehdr)
+
+phdr:                           ; Elf32_Phdr
+        dd      1               ;  p_type
+        dd      0               ;  p_offset
+        dd      $$              ;  p_vaddr
+        dd      $$              ;  p_paddr
+        dd      filesize        ;  p_filesz
+        dd      filesize        ;  p_memsz
+        dd      7               ;  p_flags
+        dd      0x1000          ;  p_align
+
+phdrsize        equ     ($ - phdr)
+
+prefixarr       db      0x2e, 0x36, 0x3e, 0x26, 0x64, 0x65, 0x67, 0xf2, 0xf3
+prefixlen       dd      9
+
+; fd 0 = random file
+; fd 1 = output file
+_start:
+
+        db      0x3e
+        db      0x26
+        db      0x64
+        db      0x65
+        db      0x67
+        db      0x36
+        db      0x2e
+        db      0xf3
+        db      0xf2
+        pushf
+
+; WORKS
+;       db      0x3e
+;       pushf
+
+; WORKS
+;       db      0x26
+;       pushf
+
+; WORKS
+;       db      0x64
+;       pushf
+
+; WORKS
+;       db      0x65
+;       pushf
+
+; WORKS, pulls lower 16 bits only
+;       db      0x66
+;       pushf
+
+; WORKS
+;       db      0x67
+;       pushf
+
+; WORKS
+;       db      0x36
+;       pushf
+
+; WORKS
+;       db      0x2e
+;       pushf
+
+; WORKS
+;       db      0xf3
+;       pushf
+
+; WORKS
+;       db      0xf2
+;       pushf
+
+; SIGILL
+;       db      0xf0
+;       popf
+
+        int3
+
+filesize        equ     ($ - $$)
+
+
diff --git a/other/prefix/prefix.c b/other/prefix/prefix.c
new file mode 100644
index 0000000..707aa45
--- /dev/null
+++ b/other/prefix/prefix.c
@@ -0,0 +1,77 @@
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/time.h>
+#include <time.h>
+
+
+int
+main (int argc, char *argv[])
+{
+        unsigned char   prefix_arr[] = {
+                0x2e,   /* cs segment override */
+                0x36,   /* ss segment override */
+                0x3e,   /* ds segment override */
+                0x26,   /* es segment override */
+                0x64,   /* fs segment override */
+                0x65,   /* gs segment override */
+                0x67,   /* adress size override */
+                0xf2,   /* repne/repnz prefix */
+                0xf3,   /* repe/repz prefix */
+        /*      0xf0,*/ /* lock prefix */
+        /*      0x66,*/ /* operand size override */
+        };
+
+        unsigned char   code[64];
+        int             n, i,
+                        clen,
+                        cwlk;
+        unsigned long   ef_should,
+                        ef_is;
+
+
+        srandom (time (NULL));
+
+        for (n = 0 ; n < 32 ; ++n) {
+                clen = random () % 14;
+                clen += 1;
+
+                memset (code, '\x00', sizeof (code));
+
+                for (cwlk = 0 ; clen > 0 ; --clen, ++cwlk) {
+                        code[cwlk] = prefix_arr[random () %
+                                (sizeof (prefix_arr) / sizeof (prefix_arr[0]))];
+                }
+                code[cwlk++] = 0x9c;    /* pushf */
+                code[cwlk++] = 0x5a;    /* popl %edx */
+                code[cwlk] = 0xc3;      /* ret */
+
+                printf ("%4d (%2d):", n, cwlk);
+                for (i = 0 ; i < cwlk ; ++i)
+                        printf (" %02x", code[i]);
+                printf ("\n");
+
+                printf ("\tef 0x%08lx  got 0x%08lx\n", ef_should, ef_is);
+
+                __asm__ __volatile__ ("
+                        pushf
+                        popl    %%eax
+                        pushl   $0x41414141
+                        call    *%%edx
+                        addl    $4, %%esp"
+                        : "=a" (ef_should), "=d" (ef_is)
+                        : "d" ((unsigned long) code)
+                );
+
+                if (ef_should != ef_is) {
+                        printf ("\tATTENTION: difference detected.\n");
+
+                        exit (EXIT_FAILURE);
+                }
+        }
+
+        exit (EXIT_SUCCESS);
+}
+
+