WebSVN – HelenOS-historic – Diff – /kernel/trunk/generic/src/lib/elf.c

 /*
  * Copyright (C) 2006 Sergey Bondari
  * All rights reserved.
+ *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
+ *
  * - Redistributions of source code must retain the above copyright
  *   notice, this list of conditions and the following disclaimer.
  * - Redistributions in binary form must reproduce the above copyright
  *   notice, this list of conditions and the following disclaimer in the
  *   documentation and/or other materials provided with the distribution.
  * - The name of the author may not be used to endorse or promote products
  *   derived from this software without specific prior written permission.
+ *
  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <elf.h>
 #include <debug.h>
 #include <arch/types.h>
 #include <typedefs.h>
 #include <mm/as.h>
 #include <mm/frame.h>
+#include <mm/slab.h>
 #include <print.h>
 #include <align.h>
+#include <memstr.h>
+#include <macros.h>
 static char *error_codes[] = {
     "no error",
     "invalid image",
     "address space error",
     "incompatible image",
     "unsupported image type",
     "irrecoverable error"
 };
-static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
+static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
+static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as);
-static int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as);
+static int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as);
 /** ELF loader
+ *
  * @param header Pointer to ELF header in memory
  * @param as Created and properly mapped address space
  * @return EE_OK on success
  */
 int elf_load(elf_header_t *header, as_t * as)
+{
     int i, rc;
     /* Identify ELF */
     if (header->e_ident[EI_MAG0] != ELFMAG0 || header->e_ident[EI_MAG1] != ELFMAG1 ||
         header->e_ident[EI_MAG2] != ELFMAG2 || header->e_ident[EI_MAG3] != ELFMAG3) {
         return EE_INVALID;
+    }
     /* Identify ELF compatibility */
     if (header->e_ident[EI_DATA] != ELF_DATA_ENCODING || header->e_machine != ELF_MACHINE ||
         header->e_ident[EI_VERSION] != EV_CURRENT || header->e_version != EV_CURRENT ||
         header->e_ident[EI_CLASS] != ELF_CLASS) {
         return EE_INCOMPATIBLE;
+    }
-    if (header->e_phentsize != sizeof(elf_ph_entry_t))
+    if (header->e_phentsize != sizeof(elf_segment_header_t))
+        return EE_INCOMPATIBLE;
+    if (header->e_shentsize != sizeof(elf_section_header_t))
         return EE_INCOMPATIBLE;
     /* Check if the object type is supported. */
     if (header->e_type != ET_EXEC)
         return EE_UNSUPPORTED;
-    /* Walk through all program header entries and process them. */
+    /* Walk through all segment headers and process them. */
     for (i = 0; i < header->e_phnum; i++) {
-        rc = program_header_entry(header, &((elf_ph_entry_t *)(((__u8 *) header) + header->e_phoff))[i], as);
+        rc = segment_header(&((elf_segment_header_t *)(((__u8 *) header) + header->e_phoff))[i], header, as);
+        if (rc != EE_OK)
+            return rc;
+    }
+    /* Inspect all section headers and proccess them. */
+    for (i = 0; i < header->e_shnum; i++) {
+        rc = section_header(&((elf_section_header_t *)(((__u8 *) header) + header->e_shoff))[i], header, as);
         if (rc != EE_OK)
             return rc;
+    }
     return EE_OK;
+}
 /** Print error message according to error code.
+ *
  * @param rc Return code returned by elf_load().
+ *
  * @return NULL terminated description of error.
  */
 char *elf_error(int rc)
+{
     ASSERT(rc < sizeof(error_codes)/sizeof(char *));
     return error_codes[rc];
+}
-/** Process program header entry.
+/** Process segment header.
+ *
- * @param entry Program header entry.
+ * @param entry Segment header.
+ * @param elf ELF header.
  * @param as Address space into wich the ELF is being loaded.
+ *
  * @return EE_OK on success, error code otherwise.
  */
-static int program_header_entry(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
+static int segment_header(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
+{
     switch (entry->p_type) {
         case PT_NULL:
         case PT_PHDR:
         break;
         case PT_LOAD:
-        return load_segment(header, entry, as);
+        return load_segment(entry, elf, as);
         break;
         case PT_DYNAMIC:
         case PT_INTERP:
         case PT_SHLIB:
         case PT_NOTE:
         case PT_LOPROC:
         case PT_HIPROC:
         default:
         return EE_UNSUPPORTED;
         break;
+    }
     return EE_OK;
+}
 /** Load segment described by program header entry.
+ *
  * @param entry Program header entry describing segment to be loaded.
+ * @param elf ELF header.
  * @parma as Address space into wich the ELF is being loaded.
+ *
  * @return EE_OK on success, error code otherwise.
  */
-int load_segment(elf_header_t *header, elf_ph_entry_t *entry, as_t *as)
+int load_segment(elf_segment_header_t *entry, elf_header_t *elf, as_t *as)
+{
     as_area_t *a;
     int i, type = 0;
+    size_t segment_size;
+    __u8 *segment;
     if (entry->p_align > 1) {
         if ((entry->p_offset % entry->p_align) != (entry->p_vaddr % entry->p_align)) {
             return EE_INVALID;
+        }
+    }
     /*
      * Check if the segment doesn't interfere with kernel address space.
      */
     if (entry->p_vaddr + ALIGN_UP(entry->p_memsz, PAGE_SIZE) >= USER_ADDRESS_SPACE_END)
         return EE_MEMORY;
     if (entry->p_flags & PF_X) {
         type = AS_AREA_TEXT;
     } else if (entry->p_flags & PF_W) {
         type = AS_AREA_DATA;
     } else {
         return EE_UNSUPPORTED;
+    }
+    /*
+     * Check if the virtual address starts on page boundary.
+     */
+    if (ALIGN_UP(entry->p_vaddr, PAGE_SIZE) != entry->p_vaddr)
+        return EE_UNSUPPORTED;
+    /*
+     * Copying the segment out is certainly necessary for segments with p_filesz < p_memsz
+     * because of the effect of .bss-like sections. For security reasons, it looks like a
+     * good idea to copy the segment anyway.
+     */
+    segment_size = ALIGN_UP(max(entry->p_filesz, entry->p_memsz), PAGE_SIZE);
+    segment = malloc(segment_size, 0);
+    if (entry->p_filesz < entry->p_memsz)
+        memsetb((__address) (segment + entry->p_filesz), segment_size - entry->p_filesz, 0);
+    memcpy(segment, (void *) (((__address) elf) + entry->p_offset), entry->p_filesz);
     a = as_area_create(as, AS_AREA_TEXT, SIZE2FRAMES(entry->p_memsz), entry->p_vaddr);
     if (!a)
         return EE_IRRECOVERABLE;
     for (i = 0; i < SIZE2FRAMES(entry->p_filesz); i++) {
-        as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) header) + entry->p_offset + i*PAGE_SIZE));
+        as_set_mapping(as, entry->p_vaddr + i*PAGE_SIZE, KA2PA(((__address) segment) + i*PAGE_SIZE));
+    }
+    return EE_OK;
+}
+/** Process section header.
+ *
+ * @param entry Segment header.
+ * @param elf ELF header.
+ * @param as Address space into wich the ELF is being loaded.
+ *
+ * @return EE_OK on success, error code otherwise.
+ */
+static int section_header(elf_section_header_t *entry, elf_header_t *elf, as_t *as)
+{
+    switch (entry->sh_type) {
+        default:
+        break;
+    }
     return EE_OK;
+}

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/generic/src/lib/elf.c – Rev 938 → 952