Improve MZ binary format parsing

librz/bin/format/mz/mz.c

@@ -64,7 +64,7 @@ RzPVector /*<RzBinSection *>*/ *rz_bin_mz_get_segments(const struct rz_bin_mz_ob
 	void **iter;
 	RzBinSection *section;
 	MZ_image_relocation_entry *relocs;
-	int i, num_relocs, section_number;
+	int i, num_relocs;
 	ut16 ss;
 
 	if (!bin || !bin->dos_header) {
@@ -137,32 +137,65 @@ RzPVector /*<RzBinSection *>*/ *rz_bin_mz_get_segments(const struct rz_bin_mz_ob
 	}
 
 	/* Fixup sizes and addresses, set name, permissions and set add flag */
-	section_number = 0;
-	rz_pvector_foreach (seg_vec, iter) {
+	ut64 index = 0;
+	rz_pvector_enumerate (seg_vec, iter, index) {
 		section = *iter;
-		section->name = rz_str_newf("seg_%03d", section_number);
-		if (section_number) {
+		section->name = rz_str_newf("seg_%03" PFMT64u, index);
+		if (index) {
 			// calculate current index in loop by subtracting base ptr
-			ut32 ptr_gap = iter - (void **)seg_vec->v.a;
-			ut32 cur_index = ptr_gap / sizeof(void **);
 			RzBinSection *p_section = NULL;
-			if (cur_index == 0) {
-				p_section = rz_pvector_tail(seg_vec);
-			} else {
-				p_section = rz_pvector_at(seg_vec, cur_index - 1);
-			}
+			p_section = rz_pvector_at(seg_vec, index - 1);
 			p_section->size = section->vaddr - p_section->vaddr;
 			p_section->vsize = p_section->size;
 		}
 		section->vsize = section->size;
 		section->paddr = rz_bin_mz_la_to_pa(bin, section->vaddr);
-		section->perm = rz_str_rwx("rwx");
-		section_number++;
+		section->perm = RZ_PERM_RWX;
 	}
 	section = rz_pvector_tail(seg_vec);
 	section->size = bin->load_module_size - section->vaddr;
 	section->vsize = section->size;
 
+	/* Map extra data (used for bss and out-of-image stack) */
+	ut64 stack_laddr = rz_bin_mz_va_to_la(bin->dos_header->ss, bin->dos_header->sp) + sizeof(ut16);
+	ut64 stack_size_outside_image = stack_laddr > bin->load_module_size ? stack_laddr - bin->load_module_size : 0;
+	ut64 extra_data = RZ_MAX(bin->dos_header->min_extra_paragraphs * 16, stack_size_outside_image);
+
+	if (extra_data) {
+		if (!(section = rz_bin_mz_init_section(bin, section->vaddr + section->vsize))) {
+			goto err_out;
+		}
+		if (bin->load_module_size % 16) {
+			/* add extra bytes so the section get to de-facto start on a paragraph-aligned address */
+			extra_data += 16 - bin->load_module_size % 16;
+		}
+		if (extra_data % 16) {
+			/* align section size to paragraph size */
+			extra_data += 16 - extra_data % 16;
+		}
+		section->name = rz_str_dup("extra");
+		section->size = 0;
+		section->vsize = extra_data;
+		section->is_data = true;
+		section->perm = RZ_PERM_RW;
+		rz_pvector_push(seg_vec, section);
+	}
+
+	/* Map overlay as a separate section */
+	ut64 overlay_size = bin->size > bin->dos_file_size ? bin->size - bin->dos_file_size : 0;
+	if (overlay_size) {
+		ut64 start_laddr = RZ_MAX(section->vaddr + section->vsize, 0x100000); /* map at/after 1mb */
+		if (!(section = rz_bin_mz_init_section(bin, start_laddr))) {
+			goto err_out;
+		}
+		section->paddr = bin->size - overlay_size;
+		section->name = rz_str_dup("overlay");
+		section->size = overlay_size;
+		section->vsize = section->size;
+		section->perm = RZ_PERM_RWX;
+		rz_pvector_push(seg_vec, section);
+	}
+
 	return seg_vec;
 
 err_out:

test/db/formats/mz/cblp0

@@ -28,5 +28,6 @@ EXPECT=<<EOF
      paddr  size      vaddr vsize align perm name    type flags 
 ----------------------------------------------------------------
 0x00000200 0x200 0x00000000 0x200   0x0 -rwx seg_000      
+0x00000000   0x0 0x00000200  0x90   0x0 -rw- extra        
 EOF
 RUN

test/db/formats/mz/unzip

@@ -20,3 +20,21 @@ EXPECT=<<EOF
 mov bp, ax
 EOF
 RUN
+
+NAME=MZ: unzip-modified-ss-sp.exe - correct section sizes
+FILE=bins/mz/unzip-modified-ss-sp.exe
+CMDS=<<EOF
+iSt
+x 8 @ 0x100000
+EOF
+EXPECT=<<EOF
+     paddr    size      vaddr   vsize align perm name    type flags 
+--------------------------------------------------------------------
+0x00000200 0x15000 0x00000000 0x15000   0x0 -rwx seg_000      
+0x00015200   0xfce 0x00015000   0xfce   0x0 -rwx seg_001      
+0x00000000     0x0 0x00015fce  0xa1f0   0x0 -rw- extra        
+0x000161ce     0x5 0x00100000     0x5   0x0 -rwx overlay      
+- offset -  0 1  2 3  4 5  6 7  8 9  A B  C D  E F  0123456789ABCDEF
+0000:0000  6865 6c6c 6fff ffff                      hello...
+EOF
+RUN