72 lines
1.9 KiB
C
Executable file
72 lines
1.9 KiB
C
Executable file
// SPDX-License-Identifier: GPL-2.0
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#include <linux/moduleloader.h>
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#include <linux/elf.h>
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#include <linux/vmalloc.h>
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#include <linux/fs.h>
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#include <linux/string.h>
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#include <linux/kernel.h>
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int apply_relocate_add(Elf32_Shdr *sechdrs,
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const char *strtab,
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unsigned int symindex,
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unsigned int relsec,
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struct module *me)
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{
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unsigned int i;
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Elf32_Rela *rela = (void *)sechdrs[relsec].sh_addr;
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pr_debug("Applying relocate section %u to %u\n", relsec,
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sechdrs[relsec].sh_info);
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for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rela); i++) {
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/* This is where to make the change */
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uint32_t *loc =
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(uint32_t *)(sechdrs[sechdrs[relsec].sh_info].sh_addr
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+ rela[i].r_offset);
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/* This is the symbol it is referring to. Note that all
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undefined symbols have been resolved. */
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Elf32_Sym *sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
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+ ELF32_R_SYM(rela[i].r_info);
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uint32_t v = sym->st_value + rela[i].r_addend;
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switch (ELF32_R_TYPE(rela[i].r_info)) {
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case R_H8_DIR24R8:
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loc = (uint32_t *)((uint32_t)loc - 1);
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*loc = (*loc & 0xff000000) | ((*loc & 0xffffff) + v);
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break;
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case R_H8_DIR24A8:
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if (ELF32_R_SYM(rela[i].r_info))
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*loc += v;
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break;
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case R_H8_DIR32:
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case R_H8_DIR32A16:
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*loc += v;
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break;
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case R_H8_PCREL16:
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v -= (unsigned long)loc + 2;
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if ((Elf32_Sword)v > 0x7fff ||
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(Elf32_Sword)v < -(Elf32_Sword)0x8000)
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goto overflow;
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else
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*(unsigned short *)loc = v;
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break;
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case R_H8_PCREL8:
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v -= (unsigned long)loc + 1;
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if ((Elf32_Sword)v > 0x7f ||
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(Elf32_Sword)v < -(Elf32_Sword)0x80)
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goto overflow;
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else
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*(unsigned char *)loc = v;
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break;
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default:
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pr_err("module %s: Unknown relocation: %u\n",
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me->name, ELF32_R_TYPE(rela[i].r_info));
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return -ENOEXEC;
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}
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}
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return 0;
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overflow:
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pr_err("module %s: relocation offset overflow: %08x\n",
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me->name, rela[i].r_offset);
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return -ENOEXEC;
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}
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