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module: move more elf validity checks to elf_validity_check()
The symbol and strings section validation currently happen in setup_load_info() but since they are also doing validity checks move this to elf_validity_check(). Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
This commit is contained in:
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c7ee8aebf6
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1bb49db991
1 changed files with 44 additions and 35 deletions
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@ -1658,6 +1658,8 @@ static int elf_validity_check(struct load_info *info)
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Elf_Shdr *shdr, *strhdr;
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Elf_Shdr *shdr, *strhdr;
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int err;
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int err;
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unsigned int num_mod_secs = 0, mod_idx;
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unsigned int num_mod_secs = 0, mod_idx;
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unsigned int num_info_secs = 0, info_idx;
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unsigned int num_sym_secs = 0, sym_idx;
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if (info->len < sizeof(*(info->hdr))) {
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if (info->len < sizeof(*(info->hdr))) {
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pr_err("Invalid ELF header len %lu\n", info->len);
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pr_err("Invalid ELF header len %lu\n", info->len);
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@ -1761,6 +1763,8 @@ static int elf_validity_check(struct load_info *info)
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info->hdr->e_shnum);
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info->hdr->e_shnum);
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goto no_exec;
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goto no_exec;
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}
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}
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num_sym_secs++;
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sym_idx = i;
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fallthrough;
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fallthrough;
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default:
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default:
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err = validate_section_offset(info, shdr);
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err = validate_section_offset(info, shdr);
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@ -1773,6 +1777,10 @@ static int elf_validity_check(struct load_info *info)
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".gnu.linkonce.this_module") == 0) {
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".gnu.linkonce.this_module") == 0) {
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num_mod_secs++;
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num_mod_secs++;
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mod_idx = i;
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mod_idx = i;
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} else if (strcmp(info->secstrings + shdr->sh_name,
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".modinfo") == 0) {
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num_info_secs++;
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info_idx = i;
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}
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}
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if (shdr->sh_flags & SHF_ALLOC) {
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if (shdr->sh_flags & SHF_ALLOC) {
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@ -1786,6 +1794,27 @@ static int elf_validity_check(struct load_info *info)
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}
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}
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}
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}
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if (num_info_secs > 1) {
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pr_err("Only one .modinfo section must exist.\n");
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goto no_exec;
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} else if (num_info_secs == 1) {
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/* Try to find a name early so we can log errors with a module name */
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info->index.info = info_idx;
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info->name = get_modinfo(info, "name");
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}
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if (num_sym_secs != 1) {
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pr_warn("%s: module has no symbols (stripped?)\n",
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info->name ?: "(missing .modinfo section or name field)");
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goto no_exec;
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}
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/* Sets internal symbols and strings. */
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info->index.sym = sym_idx;
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shdr = &info->sechdrs[sym_idx];
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info->index.str = shdr->sh_link;
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info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
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/*
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/*
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* The ".gnu.linkonce.this_module" ELF section is special. It is
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* The ".gnu.linkonce.this_module" ELF section is special. It is
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* what modpost uses to refer to __this_module and let's use rely
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* what modpost uses to refer to __this_module and let's use rely
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@ -1802,7 +1831,8 @@ static int elf_validity_check(struct load_info *info)
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* size
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* size
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*/
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*/
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if (num_mod_secs != 1) {
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if (num_mod_secs != 1) {
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pr_err("Only one .gnu.linkonce.this_module section must exist.\n");
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pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n",
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info->name ?: "(missing .modinfo section or name field)");
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goto no_exec;
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goto no_exec;
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}
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}
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@ -1813,17 +1843,20 @@ static int elf_validity_check(struct load_info *info)
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* pedantic about it.
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* pedantic about it.
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*/
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*/
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if (shdr->sh_type == SHT_NOBITS) {
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if (shdr->sh_type == SHT_NOBITS) {
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pr_err(".gnu.linkonce.this_module section must have a size set\n");
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pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n",
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info->name ?: "(missing .modinfo section or name field)");
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goto no_exec;
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goto no_exec;
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}
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}
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if (!(shdr->sh_flags & SHF_ALLOC)) {
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if (!(shdr->sh_flags & SHF_ALLOC)) {
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pr_err(".gnu.linkonce.this_module must occupy memory during process execution\n");
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pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n",
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info->name ?: "(missing .modinfo section or name field)");
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goto no_exec;
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goto no_exec;
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}
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}
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if (shdr->sh_size != sizeof(struct module)) {
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if (shdr->sh_size != sizeof(struct module)) {
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pr_err(".gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n");
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pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n",
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info->name ?: "(missing .modinfo section or name field)");
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goto no_exec;
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goto no_exec;
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}
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}
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@ -1832,6 +1865,13 @@ static int elf_validity_check(struct load_info *info)
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/* This is temporary: point mod into copy of data. */
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/* This is temporary: point mod into copy of data. */
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info->mod = (void *)info->hdr + shdr->sh_offset;
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info->mod = (void *)info->hdr + shdr->sh_offset;
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/*
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* If we didn't load the .modinfo 'name' field earlier, fall back to
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* on-disk struct mod 'name' field.
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*/
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if (!info->name)
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info->name = info->mod->name;
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return 0;
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return 0;
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no_exec:
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no_exec:
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@ -1954,37 +1994,6 @@ static int rewrite_section_headers(struct load_info *info, int flags)
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*/
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*/
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static int setup_load_info(struct load_info *info, int flags)
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static int setup_load_info(struct load_info *info, int flags)
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{
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{
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unsigned int i;
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/* Try to find a name early so we can log errors with a module name */
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info->index.info = find_sec(info, ".modinfo");
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if (info->index.info)
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info->name = get_modinfo(info, "name");
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/* Find internal symbols and strings. */
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for (i = 1; i < info->hdr->e_shnum; i++) {
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if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
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info->index.sym = i;
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info->index.str = info->sechdrs[i].sh_link;
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info->strtab = (char *)info->hdr
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+ info->sechdrs[info->index.str].sh_offset;
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break;
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}
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}
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if (info->index.sym == 0) {
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pr_warn("%s: module has no symbols (stripped?)\n",
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info->name ?: "(missing .modinfo section or name field)");
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return -ENOEXEC;
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}
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/*
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* If we didn't load the .modinfo 'name' field earlier, fall back to
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* on-disk struct mod 'name' field.
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*/
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if (!info->name)
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info->name = info->mod->name;
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if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
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if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
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info->index.vers = 0; /* Pretend no __versions section! */
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info->index.vers = 0; /* Pretend no __versions section! */
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else
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else
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