mirror of https://gitee.com/openkylin/linux.git
module: refactor load_module part 3
Extract out the allocation and copying in from userspace, and the first set of modinfo checks. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell
parent
65b8a9b4d5
commit
40dd2560ec
122
kernel/module.c
122
kernel/module.c
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@ -1803,7 +1803,7 @@ static char *next_string(char *string, unsigned long *secsize)
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return string;
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}
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static char *get_modinfo(Elf_Shdr *sechdrs,
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static char *get_modinfo(const Elf_Shdr *sechdrs,
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unsigned int info,
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const char *tag)
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{
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@ -2109,6 +2109,73 @@ static inline void kmemleak_load_module(struct module *mod, Elf_Ehdr *hdr,
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}
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#endif
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static int copy_and_check(Elf_Ehdr **hdrp,
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const void __user *umod, unsigned long len)
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{
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int err;
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Elf_Ehdr *hdr;
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if (len < sizeof(*hdr))
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return -ENOEXEC;
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/* Suck in entire file: we'll want most of it. */
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/* vmalloc barfs on "unusual" numbers. Check here */
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if (len > 64 * 1024 * 1024 || (hdr = *hdrp = vmalloc(len)) == NULL)
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return -ENOMEM;
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if (copy_from_user(hdr, umod, len) != 0) {
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err = -EFAULT;
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goto free_hdr;
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}
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/* Sanity checks against insmoding binaries or wrong arch,
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weird elf version */
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if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
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|| hdr->e_type != ET_REL
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|| !elf_check_arch(hdr)
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|| hdr->e_shentsize != sizeof(Elf_Shdr)) {
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err = -ENOEXEC;
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goto free_hdr;
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}
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if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
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err = -ENOEXEC;
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goto free_hdr;
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}
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return 0;
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free_hdr:
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vfree(hdr);
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return err;
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}
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static int check_modinfo(struct module *mod,
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const Elf_Shdr *sechdrs,
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unsigned int infoindex, unsigned int versindex)
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{
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const char *modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
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int err;
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/* This is allowed: modprobe --force will invalidate it. */
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if (!modmagic) {
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err = try_to_force_load(mod, "bad vermagic");
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if (err)
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return err;
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} else if (!same_magic(modmagic, vermagic, versindex)) {
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printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
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mod->name, modmagic, vermagic);
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return -ENOEXEC;
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}
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if (get_modinfo(sechdrs, infoindex, "staging")) {
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add_taint_module(mod, TAINT_CRAP);
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printk(KERN_WARNING "%s: module is from the staging directory,"
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" the quality is unknown, you have been warned.\n",
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mod->name);
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}
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return 0;
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}
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static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,
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Elf_Shdr *sechdrs, const char *secstrings)
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{
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@ -2246,14 +2313,13 @@ static noinline struct module *load_module(void __user *umod,
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{
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Elf_Ehdr *hdr;
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Elf_Shdr *sechdrs;
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char *secstrings, *args, *modmagic, *strtab = NULL;
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char *staging;
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char *secstrings, *args, *strtab = NULL;
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unsigned int i;
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unsigned int symindex = 0;
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unsigned int strindex = 0;
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unsigned int modindex, versindex, infoindex, pcpuindex;
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struct module *mod;
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long err = 0;
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long err;
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unsigned long symoffs, stroffs, *strmap;
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void __percpu *percpu;
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struct _ddebug *debug = NULL;
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@ -2263,31 +2329,10 @@ static noinline struct module *load_module(void __user *umod,
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DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
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umod, len, uargs);
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if (len < sizeof(*hdr))
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return ERR_PTR(-ENOEXEC);
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/* Suck in entire file: we'll want most of it. */
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/* vmalloc barfs on "unusual" numbers. Check here */
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if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
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return ERR_PTR(-ENOMEM);
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if (copy_from_user(hdr, umod, len) != 0) {
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err = -EFAULT;
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goto free_hdr;
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}
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/* Sanity checks against insmoding binaries or wrong arch,
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weird elf version */
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if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
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|| hdr->e_type != ET_REL
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|| !elf_check_arch(hdr)
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|| hdr->e_shentsize != sizeof(*sechdrs)) {
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err = -ENOEXEC;
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goto free_hdr;
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}
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if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
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goto truncated;
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err = copy_and_check(&hdr, umod, len);
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if (err)
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return ERR_PTR(err);
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/* Convenience variables */
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sechdrs = (void *)hdr + hdr->e_shoff;
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@ -2347,26 +2392,9 @@ static noinline struct module *load_module(void __user *umod,
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goto free_hdr;
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}
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modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
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/* This is allowed: modprobe --force will invalidate it. */
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if (!modmagic) {
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err = try_to_force_load(mod, "bad vermagic");
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if (err)
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goto free_hdr;
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} else if (!same_magic(modmagic, vermagic, versindex)) {
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printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
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mod->name, modmagic, vermagic);
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err = -ENOEXEC;
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err = check_modinfo(mod, sechdrs, infoindex, versindex);
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if (err)
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goto free_hdr;
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}
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staging = get_modinfo(sechdrs, infoindex, "staging");
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if (staging) {
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add_taint_module(mod, TAINT_CRAP);
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printk(KERN_WARNING "%s: module is from the staging directory,"
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" the quality is unknown, you have been warned.\n",
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mod->name);
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}
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/* Now copy in args */
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args = strndup_user(uargs, ~0UL >> 1);
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