unfilter for arm-linux.kernel

src/p_vmlinx.cpp

@@ -397,25 +397,17 @@ void PackVmlinuxARM::buildLoader(const Filter *ft)
 {
     // prepare loader
     initLoader(stub_arm_linux_kernel_vmlinux, sizeof(stub_arm_linux_kernel_vmlinux));
-    addLoader("LINUX000",
-              (0x40==(0xf0 & ft->id)) ? "LXCKLLT1" : (ft->id ? "LXCALLT1" : ""),
-              "LXMOVEUP",
-              getDecompressorSections(),
-              NULL
-             );
+    addLoader("LINUX000", NULL);
     if (ft->id) {
         assert(ft->calls > 0);
-        if (0x40==(0xf0 & ft->id)) {
-            addLoader("LXCKLLT9", NULL);
-        }
-        else {
-            addLoader("LXCALLT9", NULL);
-        }
+        addLoader("LINUX010", NULL);
+    }
+    addLoader("LINUX020", NULL);
+    if (ft->id) {
         addFilter32(ft->id);
     }
-    addLoader("LINUX990",
-              ph.first_offset_found == 1 ? "LINUX991" : "",
-              "LINUX992,IDENTSTR,UPX1HEAD", NULL);
+    addLoader("LINUX030", getDecompressorSections(),
+              "IDENTSTR,UPX1HEAD", NULL);
 }
 
 
@@ -427,10 +419,16 @@ static bool defineFilterSymbols(Linker *linker, const Filter *ft)
     }
     assert(ft->calls > 0);
 
-    linker->defineSymbol("filter_cto", ft->cto);
-    linker->defineSymbol("filter_length",
-                         (ft->id & 0xf) % 3 == 0 ? ft->calls :
-                         ft->lastcall - ft->calls * 4);
+    if (0x50==(0xF0 & ft->id)) {
+        linker->defineSymbol("FID", ft->id);
+        linker->defineSymbol("CTO", ft->cto);
+    }
+    else {
+        linker->defineSymbol("filter_cto", ft->cto);
+        linker->defineSymbol("filter_length",
+                            (ft->id & 0xf) % 3 == 0 ? ft->calls :
+                            ft->lastcall - ft->calls * 4);
+    }
     return true;
 }
 

src/packer_f.cpp

@@ -71,7 +71,13 @@ void Packer::addFilter32(int filter_id)
     assert(isValidFilter(filter_id));
 
     if (filter_id < 0x80) {
-        if ((filter_id & 0xf) % 3 == 0) {
+        if (0x50==(0xF0 & filter_id)) {
+            addLoader("CKLLTR00",
+                ((0x50==filter_id) ? "CKLLTR50" :
+                 (0x51==filter_id) ? "CKLLTR51" : ""),
+                "CKLLTR10", NULL);
+        }
+        else if ((filter_id & 0xf) % 3 == 0) {
             if (filter_id < 0x40) {
                 addLoader("CALLTR00",
                         (filter_id > 0x20) ? "CTCLEVE1" : "",

src/stub/src/arm-linux.kernel.vmlinux.S

@@ -54,26 +54,84 @@ decompress_kernel:  # (char *out, char *tmp, char *tmp_end, int arch_id)
 
 // Value stored from r1 to memory will be overwritten by outsize.
         stmdb r1!,{r0,r1,r2,r3,sp}  // &indata, space, &outdata, arch_id, sp_in
-        ldr r3,2*4+.L10  // method
+        loadcon8 3,METHOD  // mov r3,#METHOD
         mov sp,r1  // switch stacks to tmp_end area (64KB)
-        ldr r1,0*4+.L10  // insize
+        ldr r1,1f  // insize
         str r3,[sp,#-4]!  // method
-        ldr r3,1*4+.L10  // outsize
+        ldr r3,2f  // outsize
         str r3,[sp,#2*4]  // outsize
         add r3,sp, #2*4  // &outsize
-        bl .L20  // (&indata, insize, &outdata, &outsize, method)
+        bl decompressor  // (&indata, insize, &outdata, &outsize, method)
+        b 3f
+1:
+        .long   COMPRESSED_LENGTH
+2:
+        .long UNCOMPRESSED_LENGTH
+3:
 spin:
         cmp r0,#0  // check for success
         bne spin
 
+section         LINUX010
+        ldr r0,[sp,#3*4]  // &outdata
+        ldr r1,[sp,#2*4]  // outsize
+        loadcon8 2,CTO  // mov r2,#CTO
+        loadcon8 3,FID  // mov r3,#FID
+        bl unfilter  // unfilter(&outdata, outsize, cto, fid)
+
+section         LINUX020
         ldmia sp,{r0,r1,r2,r3,ip,sp,lr}  // method, &indata, outsize, &outdata, arch_id, sp_in, retaddr
         add r0,r2,r3  // rv= &outdata[outsize]
         mov pc,lr  // return
-.L10:
-        .long   COMPRESSED_LENGTH
-        .long UNCOMPRESSED_LENGTH
-        .long METHOD
-.L20:
+
+// =============
+// ============= UNFILTER
+// =============
+section         CKLLTR00
+//f_unfilter:  @ (char *ptr, uint len, uint cto, uint fid)
+        ptr  .req r0
+        len  .req r1
+        cto  .req r2  @ unused
+        fid  .req r3
+
+        t1   .req r2
+        t2   .req r3
+unfilter:
+        and fid,fid,#0xff
+section         CKLLTR50
+        cmp fid,#0x50  @ last use of fid
+section         CKLLTR51
+        cmp fid,#0x51  @ last use of fid
+
+section         CKLLTR10
+        movne pc,lr  @ no-op if not filter 0x50
+
+        movs  len,len,lsr #2  @ word count
+        cmpne ptr,#0
+        moveq pc,lr  @ no-op if either len or ptr is 0
+
+top_unf:
+        sub len,len,#1
+        ldr t1,[ptr,len,lsl #2]
+        and t2,t1,#0x0f<<24
+        cmp t2,   #0x0b<<24; bne tst_unf  @ not 'bl' subroutine call
+        and t2,t1,#0xff<<24  @ all the non-displacement bits
+        sub t1,t1,len  @ convert to word-relative displacement
+        bic t1,t1,#0xff<<24  @ restrict to displacement field
+        orr t1,t1,t2  @ re-combine
+        str t1,[ptr,len,lsl #2]
+tst_unf:
+        cmp len,#0
+        bne top_unf
+        mov pc,lr
+
+        .unreq ptr
+        .unreq len
+        .unreq cto
+        .unreq fid
+
+section         LINUX030
+decompressor:
 /*
   r0= inptr
   r1= insize
@@ -82,17 +140,6 @@ spin:
   sp/ method
 */
 
-section         LXCALLT1
-        mvn ip,#1
-        bkpt
-section         LXCKLLT1
-        mvn ip,#2
-        bkpt
-        .long filter_cto,filter_length
-section         LXMOVEUP
-        mvn ip,#3
-        bkpt
-
 // =============
 // ============= DECOMPRESSION
 // =============
@@ -108,10 +155,6 @@ section NRV2E
 
 #include "arch/arm/v5a/lzma_d.S"
 
-// =============
-// ============= UNFILTER
-// =============
-
 #if 0  /*{ remind me about parameters for unfilter? */
 section         LXCKLLT9
                 pop     ecx     // MATCH05  len