diff options
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 157 |
1 files changed, 97 insertions, 60 deletions
diff --git a/kernel/module.c b/kernel/module.c index 5c26a76e800b..46a5c2ed1928 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -337,12 +337,12 @@ static inline void add_taint_module(struct module *mod, unsigned flag, * A thread that wants to hold a reference to a module only while it * is running can call this to safely exit. nfsd and lockd use this. */ -void __noreturn __module_put_and_exit(struct module *mod, long code) +void __noreturn __module_put_and_kthread_exit(struct module *mod, long code) { module_put(mod); - do_exit(code); + kthread_exit(code); } -EXPORT_SYMBOL(__module_put_and_exit); +EXPORT_SYMBOL(__module_put_and_kthread_exit); /* Find a module section: 0 means not found. */ static unsigned int find_sec(const struct load_info *info, const char *name) @@ -958,7 +958,6 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, } } - /* Stop the machine so refcounts can't move and disable module. */ ret = try_stop_module(mod, flags, &forced); if (ret != 0) goto out; @@ -2884,12 +2883,13 @@ static int module_sig_check(struct load_info *info, int flags) const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1; const char *reason; const void *mod = info->hdr; - + bool mangled_module = flags & (MODULE_INIT_IGNORE_MODVERSIONS | + MODULE_INIT_IGNORE_VERMAGIC); /* - * Require flags == 0, as a module with version information - * removed is no longer the module that was signed + * Do not allow mangled modules as a module with version information + * removed is no longer the module that was signed. */ - if (flags == 0 && + if (!mangled_module && info->len > markerlen && memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) { /* We truncate the module to discard the signature */ @@ -2942,7 +2942,11 @@ static int module_sig_check(struct load_info *info, int flags) static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr) { +#if defined(CONFIG_64BIT) + unsigned long long secend; +#else unsigned long secend; +#endif /* * Check for both overflow and offset/size being @@ -2967,14 +2971,29 @@ static int elf_validity_check(struct load_info *info) Elf_Shdr *shdr, *strhdr; int err; - if (info->len < sizeof(*(info->hdr))) - return -ENOEXEC; + if (info->len < sizeof(*(info->hdr))) { + pr_err("Invalid ELF header len %lu\n", info->len); + goto no_exec; + } - if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0 - || info->hdr->e_type != ET_REL - || !elf_check_arch(info->hdr) - || info->hdr->e_shentsize != sizeof(Elf_Shdr)) - return -ENOEXEC; + if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) { + pr_err("Invalid ELF header magic: != %s\n", ELFMAG); + goto no_exec; + } + if (info->hdr->e_type != ET_REL) { + pr_err("Invalid ELF header type: %u != %u\n", + info->hdr->e_type, ET_REL); + goto no_exec; + } + if (!elf_check_arch(info->hdr)) { + pr_err("Invalid architecture in ELF header: %u\n", + info->hdr->e_machine); + goto no_exec; + } + if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) { + pr_err("Invalid ELF section header size\n"); + goto no_exec; + } /* * e_shnum is 16 bits, and sizeof(Elf_Shdr) is @@ -2983,8 +3002,10 @@ static int elf_validity_check(struct load_info *info) */ if (info->hdr->e_shoff >= info->len || (info->hdr->e_shnum * sizeof(Elf_Shdr) > - info->len - info->hdr->e_shoff)) - return -ENOEXEC; + info->len - info->hdr->e_shoff)) { + pr_err("Invalid ELF section header overflow\n"); + goto no_exec; + } info->sechdrs = (void *)info->hdr + info->hdr->e_shoff; @@ -2992,13 +3013,19 @@ static int elf_validity_check(struct load_info *info) * Verify if the section name table index is valid. */ if (info->hdr->e_shstrndx == SHN_UNDEF - || info->hdr->e_shstrndx >= info->hdr->e_shnum) - return -ENOEXEC; + || info->hdr->e_shstrndx >= info->hdr->e_shnum) { + pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n", + info->hdr->e_shstrndx, info->hdr->e_shstrndx, + info->hdr->e_shnum); + goto no_exec; + } strhdr = &info->sechdrs[info->hdr->e_shstrndx]; err = validate_section_offset(info, strhdr); - if (err < 0) + if (err < 0) { + pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type); return err; + } /* * The section name table must be NUL-terminated, as required @@ -3006,8 +3033,10 @@ static int elf_validity_check(struct load_info *info) * strings in the section safe. */ info->secstrings = (void *)info->hdr + strhdr->sh_offset; - if (info->secstrings[strhdr->sh_size - 1] != '\0') - return -ENOEXEC; + if (info->secstrings[strhdr->sh_size - 1] != '\0') { + pr_err("ELF Spec violation: section name table isn't null terminated\n"); + goto no_exec; + } /* * The code assumes that section 0 has a length of zero and @@ -3015,8 +3044,11 @@ static int elf_validity_check(struct load_info *info) */ if (info->sechdrs[0].sh_type != SHT_NULL || info->sechdrs[0].sh_size != 0 - || info->sechdrs[0].sh_addr != 0) - return -ENOEXEC; + || info->sechdrs[0].sh_addr != 0) { + pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n", + info->sechdrs[0].sh_type); + goto no_exec; + } for (i = 1; i < info->hdr->e_shnum; i++) { shdr = &info->sechdrs[i]; @@ -3026,8 +3058,12 @@ static int elf_validity_check(struct load_info *info) continue; case SHT_SYMTAB: if (shdr->sh_link == SHN_UNDEF - || shdr->sh_link >= info->hdr->e_shnum) - return -ENOEXEC; + || shdr->sh_link >= info->hdr->e_shnum) { + pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n", + shdr->sh_link, shdr->sh_link, + info->hdr->e_shnum); + goto no_exec; + } fallthrough; default: err = validate_section_offset(info, shdr); @@ -3049,6 +3085,9 @@ static int elf_validity_check(struct load_info *info) } return 0; + +no_exec: + return -ENOEXEC; } #define COPY_CHUNK_SIZE (16*PAGE_SIZE) @@ -3135,9 +3174,12 @@ out: return err; } -static void free_copy(struct load_info *info) +static void free_copy(struct load_info *info, int flags) { - vfree(info->hdr); + if (flags & MODULE_INIT_COMPRESSED_FILE) + module_decompress_cleanup(info); + else + vfree(info->hdr); } static int rewrite_section_headers(struct load_info *info, int flags) @@ -3683,12 +3725,6 @@ static noinline int do_init_module(struct module *mod) } freeinit->module_init = mod->init_layout.base; - /* - * We want to find out whether @mod uses async during init. Clear - * PF_USED_ASYNC. async_schedule*() will set it. - */ - current->flags &= ~PF_USED_ASYNC; - do_mod_ctors(mod); /* Start the module */ if (mod->init != NULL) @@ -3714,22 +3750,13 @@ static noinline int do_init_module(struct module *mod) /* * We need to finish all async code before the module init sequence - * is done. This has potential to deadlock. For example, a newly - * detected block device can trigger request_module() of the - * default iosched from async probing task. Once userland helper - * reaches here, async_synchronize_full() will wait on the async - * task waiting on request_module() and deadlock. + * is done. This has potential to deadlock if synchronous module + * loading is requested from async (which is not allowed!). * - * This deadlock is avoided by perfomring async_synchronize_full() - * iff module init queued any async jobs. This isn't a full - * solution as it will deadlock the same if module loading from - * async jobs nests more than once; however, due to the various - * constraints, this hack seems to be the best option for now. - * Please refer to the following thread for details. - * - * http://thread.gmane.org/gmane.linux.kernel/1420814 + * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous + * request_module() from async workers") for more details. */ - if (!mod->async_probe_requested && (current->flags & PF_USED_ASYNC)) + if (!mod->async_probe_requested) async_synchronize_full(); ftrace_free_mem(mod, mod->init_layout.base, mod->init_layout.base + @@ -3940,10 +3967,8 @@ static int load_module(struct load_info *info, const char __user *uargs, * sections. */ err = elf_validity_check(info); - if (err) { - pr_err("Module has invalid ELF structures\n"); + if (err) goto free_copy; - } /* * Everything checks out, so set up the section info @@ -4088,7 +4113,7 @@ static int load_module(struct load_info *info, const char __user *uargs, } /* Get rid of temporary copy. */ - free_copy(info); + free_copy(info, flags); /* Done! */ trace_module_load(mod); @@ -4137,7 +4162,7 @@ static int load_module(struct load_info *info, const char __user *uargs, module_deallocate(mod, info); free_copy: - free_copy(info); + free_copy(info, flags); return err; } @@ -4164,7 +4189,8 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) { struct load_info info = { }; - void *hdr = NULL; + void *buf = NULL; + int len; int err; err = may_init_module(); @@ -4174,15 +4200,24 @@ SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags) pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags); if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS - |MODULE_INIT_IGNORE_VERMAGIC)) + |MODULE_INIT_IGNORE_VERMAGIC + |MODULE_INIT_COMPRESSED_FILE)) return -EINVAL; - err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL, + len = kernel_read_file_from_fd(fd, 0, &buf, INT_MAX, NULL, READING_MODULE); - if (err < 0) - return err; - info.hdr = hdr; - info.len = err; + if (len < 0) + return len; + + if (flags & MODULE_INIT_COMPRESSED_FILE) { + err = module_decompress(&info, buf, len); + vfree(buf); /* compressed data is no longer needed */ + if (err) + return err; + } else { + info.hdr = buf; + info.len = len; + } return load_module(&info, uargs, flags); } @@ -4462,6 +4497,8 @@ int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *, mod, kallsyms_symbol_value(sym)); if (ret != 0) goto out; + + cond_resched(); } } out: |