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>
diff --git a/kernel/module.c b/kernel/module.c
index 19ddcb0..d8faf35 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -1803,7 +1803,7 @@
return string;
}
-static char *get_modinfo(Elf_Shdr *sechdrs,
+static char *get_modinfo(const Elf_Shdr *sechdrs,
unsigned int info,
const char *tag)
{
@@ -2109,6 +2109,73 @@
}
#endif
+static int copy_and_check(Elf_Ehdr **hdrp,
+ const void __user *umod, unsigned long len)
+{
+ int err;
+ Elf_Ehdr *hdr;
+
+ if (len < sizeof(*hdr))
+ return -ENOEXEC;
+
+ /* Suck in entire file: we'll want most of it. */
+ /* vmalloc barfs on "unusual" numbers. Check here */
+ if (len > 64 * 1024 * 1024 || (hdr = *hdrp = vmalloc(len)) == NULL)
+ return -ENOMEM;
+
+ if (copy_from_user(hdr, umod, len) != 0) {
+ err = -EFAULT;
+ goto free_hdr;
+ }
+
+ /* Sanity checks against insmoding binaries or wrong arch,
+ weird elf version */
+ if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
+ || hdr->e_type != ET_REL
+ || !elf_check_arch(hdr)
+ || hdr->e_shentsize != sizeof(Elf_Shdr)) {
+ err = -ENOEXEC;
+ goto free_hdr;
+ }
+
+ if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr)) {
+ err = -ENOEXEC;
+ goto free_hdr;
+ }
+ return 0;
+
+free_hdr:
+ vfree(hdr);
+ return err;
+}
+
+static int check_modinfo(struct module *mod,
+ const Elf_Shdr *sechdrs,
+ unsigned int infoindex, unsigned int versindex)
+{
+ const char *modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
+ int err;
+
+ /* This is allowed: modprobe --force will invalidate it. */
+ if (!modmagic) {
+ err = try_to_force_load(mod, "bad vermagic");
+ if (err)
+ return err;
+ } else if (!same_magic(modmagic, vermagic, versindex)) {
+ printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
+ mod->name, modmagic, vermagic);
+ return -ENOEXEC;
+ }
+
+ if (get_modinfo(sechdrs, infoindex, "staging")) {
+ add_taint_module(mod, TAINT_CRAP);
+ printk(KERN_WARNING "%s: module is from the staging directory,"
+ " the quality is unknown, you have been warned.\n",
+ mod->name);
+ }
+ return 0;
+}
+
static void find_module_sections(struct module *mod, Elf_Ehdr *hdr,
Elf_Shdr *sechdrs, const char *secstrings)
{
@@ -2246,14 +2313,13 @@
{
Elf_Ehdr *hdr;
Elf_Shdr *sechdrs;
- char *secstrings, *args, *modmagic, *strtab = NULL;
- char *staging;
+ char *secstrings, *args, *strtab = NULL;
unsigned int i;
unsigned int symindex = 0;
unsigned int strindex = 0;
unsigned int modindex, versindex, infoindex, pcpuindex;
struct module *mod;
- long err = 0;
+ long err;
unsigned long symoffs, stroffs, *strmap;
void __percpu *percpu;
struct _ddebug *debug = NULL;
@@ -2263,31 +2329,10 @@
DEBUGP("load_module: umod=%p, len=%lu, uargs=%p\n",
umod, len, uargs);
- if (len < sizeof(*hdr))
- return ERR_PTR(-ENOEXEC);
- /* Suck in entire file: we'll want most of it. */
- /* vmalloc barfs on "unusual" numbers. Check here */
- if (len > 64 * 1024 * 1024 || (hdr = vmalloc(len)) == NULL)
- return ERR_PTR(-ENOMEM);
-
- if (copy_from_user(hdr, umod, len) != 0) {
- err = -EFAULT;
- goto free_hdr;
- }
-
- /* Sanity checks against insmoding binaries or wrong arch,
- weird elf version */
- if (memcmp(hdr->e_ident, ELFMAG, SELFMAG) != 0
- || hdr->e_type != ET_REL
- || !elf_check_arch(hdr)
- || hdr->e_shentsize != sizeof(*sechdrs)) {
- err = -ENOEXEC;
- goto free_hdr;
- }
-
- if (len < hdr->e_shoff + hdr->e_shnum * sizeof(Elf_Shdr))
- goto truncated;
+ err = copy_and_check(&hdr, umod, len);
+ if (err)
+ return ERR_PTR(err);
/* Convenience variables */
sechdrs = (void *)hdr + hdr->e_shoff;
@@ -2347,26 +2392,9 @@
goto free_hdr;
}
- modmagic = get_modinfo(sechdrs, infoindex, "vermagic");
- /* This is allowed: modprobe --force will invalidate it. */
- if (!modmagic) {
- err = try_to_force_load(mod, "bad vermagic");
- if (err)
- goto free_hdr;
- } else if (!same_magic(modmagic, vermagic, versindex)) {
- printk(KERN_ERR "%s: version magic '%s' should be '%s'\n",
- mod->name, modmagic, vermagic);
- err = -ENOEXEC;
+ err = check_modinfo(mod, sechdrs, infoindex, versindex);
+ if (err)
goto free_hdr;
- }
-
- staging = get_modinfo(sechdrs, infoindex, "staging");
- if (staging) {
- add_taint_module(mod, TAINT_CRAP);
- printk(KERN_WARNING "%s: module is from the staging directory,"
- " the quality is unknown, you have been warned.\n",
- mod->name);
- }
/* Now copy in args */
args = strndup_user(uargs, ~0UL >> 1);