module: be more picky about allowing missing module versions

We allow missing __versions sections, because modprobe --force strips
it.  It makes less sense to allow sections where there's no version
for a specific symbol the module uses, so disallow that.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 2 deletions

diff --git a/kernel/module.c b/kernel/module.c
index 8e4528c9909..2584c0e2762 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -917,6 +917,10 @@ static int check_version(Elf_Shdr *sechdrs,
         if (!crc)
                 return 1;
 
+        /* No versions at all?  modprobe --force does this. */
+        if (versindex == 0)
+                return try_to_force_load(mod, symname) == 0;
+
         versions = (void *) sechdrs[versindex].sh_addr;
         num_versions = sechdrs[versindex].sh_size
                 / sizeof(struct modversion_info);
@@ -932,8 +936,9 @@ static int check_version(Elf_Shdr *sechdrs,
                 goto bad_version;
         }
 
-        if (!try_to_force_load(mod, symname))
-                return 1;
+        printk(KERN_WARNING "%s: no symbol version for %s\n",
+               mod->name, symname);
+        return 0;
 
 bad_version:
         printk("%s: disagrees about version of symbol %s\n",