[PARISC] Fix fs/binfmt_som.c

Fix compilation (missing include of a.out.h)
Fix security hole (need to call unshare_files)
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>

fs/binfmt_som.c

@@ -29,6 +29,7 @@
 #include <linux/personality.h>
 #include <linux/init.h>
 
+#include <asm/a.out.h>
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 
@@ -194,6 +195,7 @@ load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 	unsigned long som_entry;
 	struct som_hdr *som_ex;
 	struct som_exec_auxhdr *hpuxhdr;
+	struct files_struct *files;
 
 	/* Get the exec-header */
 	som_ex = (struct som_hdr *) bprm->buf;
@@ -208,15 +210,27 @@ load_som_binary(struct linux_binprm * bprm, struct pt_regs * regs)
 	size = som_ex->aux_header_size;
 	if (size > SOM_PAGESIZE)
 		goto out;
-	hpuxhdr = (struct som_exec_auxhdr *) kmalloc(size, GFP_KERNEL);
+	hpuxhdr = kmalloc(size, GFP_KERNEL);
 	if (!hpuxhdr)
 		goto out;
 
 	retval = kernel_read(bprm->file, som_ex->aux_header_location,
 			(char *) hpuxhdr, size);
+	if (retval != size) {
+		if (retval >= 0)
+			retval = -EIO;
+		goto out_free;
+	}
+
+	files = current->files; /* Refcounted so ok */
+	retval = unshare_files();
 	if (retval < 0)
 		goto out_free;
-#error "Fix security hole before enabling me"
+	if (files == current->files) {
+		put_files_struct(files);
+		files = NULL;
+	}
+
 	retval = get_unused_fd();
 	if (retval < 0)
 		goto out_free;