Import Dev86-0.0.6.tar.gzv0.0.6

9 files changed, 204 insertions, 21 deletions

diff --git a/elksemu/Kernel_patch b/elksemu/Kernel_patch
index 451455f..cc4ca40 100644
--- a/elksemu/Kernel_patch
+++ b/elksemu/Kernel_patch
@@ -1,6 +1,8 @@
-
 This kernel patch allows you to run Linux-8086 executables transparently
-on a Linux-i386 system. It requires V0.0.2 of elksemu in "/lib/elksemu".
+on a Linux-i386 (1.2.13) system.
+It requires V0.0.2 or better of elksemu in the file "/lib/elksemu".
+
+If you are using kernel 1.3.* or later try the module: binfmt_elks.o
 
 --- orig-13/fs/exec.c	Sun Sep 24 13:22:37 1995
 +++ linux/fs/exec.c	Sun Feb 11 20:11:47 1996
diff --git a/elksemu/Makefile b/elksemu/Makefile
index cee13ac..92aa516 100644
--- a/elksemu/Makefile
+++ b/elksemu/Makefile
@@ -11,8 +11,8 @@ OBJ=elks.o elks_sys.o elks_signal.o
 elksemu:	$(OBJ)
 		$(CC) $(CFLAGS) -o elksemu $(OBJ)
 
-$(OBJ):		elks.h
 elks_sys.o:	call_tab.v
+$(OBJ):		elks.h
 
 call_tab.v:	dummy
 	-cp -p ../libc/syscall/call_tab.v . 2>/dev/null
@@ -20,10 +20,24 @@ call_tab.v:	dummy
 
 dummy:
 
-# The kernel patch _requires_ this location.
+# The kernel patch or module _requires_ this location.
 install: elksemu
-	install -s -m 755 elksemu /lib/elksemu
+	install -s -o root -g root -m 4111 elksemu /lib/elksemu
 	tar cvf V-files.tar call_tab.v defn_tab.v
 
 clean:
 	rm -f $(OBJ) elksemu call_tab.v defn_tab.v
+
+module: binfmt_elks.o
+
+# HOW to compile the module...
+
+# This matches my compile; yours may be different.
+binfmt_elks.o:	binfmt_elks.c
+	gcc -O -c -fomit-frame-pointer -DCPU=386 -D__KERNEL__ -DMODULE -DMODVERSIONS -include /usr/include/linux/modversions.h binfmt_elks.c
+
+# This is another option
+#	gcc -O -c -fomit-frame-pointer -DCPU=386 -D__KERNEL__ -DMODULE binfmt_elks.c
+# Or this ...
+#	gcc -O -c -fomit-frame-pointer -D__KERNEL__ -DMODULE -DCONFIG_MODVERSIONS binfmt_elks.c
+
diff --git a/elksemu/Security b/elksemu/Security
new file mode 100644
index 0000000..2fbef8b
--- /dev/null
+++ b/elksemu/Security
@@ -0,0 +1,20 @@
+The install scripts now install /lib/elksemu as a suid-root executable.
+This gives two additional facilities when running elks executables.
+
+1) It is now possible to run programs that are execute only, without
+   read permission, as the file is opened while we have superuser
+   access.
+
+2) If the ELKS executable has suid or sgid bits set these will be honoured.
+
+The user now needs execute access to run an executable, this is checked.
+
+If the executable does not have either suid/sgid bits set then all
+extra permissions will be dropped within the first few lines of the
+main() function. Because of this you need only check this tiny
+piece of code if you intend never to use suid.
+
+If you have any problem with elksemu being suid-root the program will
+run as before, with no complaints, if you remove the suid permission.
+
+Rob.
diff --git a/elksemu/V-files.tar b/elksemu/V-files.tar
index c5e6082..3e1227c 100644
--- a/elksemu/V-files.tar
+++ b/elksemu/V-files.tar
diff --git a/elksemu/Version b/elksemu/Version
index 38a680f..66a1fd7 100644
--- a/elksemu/Version
+++ b/elksemu/Version
@@ -1 +1 @@
-Version elksemu-0.0.4
+Version elksemu-0.0.6
diff --git a/elksemu/binfmt_elks.c b/elksemu/binfmt_elks.c
new file mode 100644
index 0000000..09e5a29
--- /dev/null
+++ b/elksemu/binfmt_elks.c
@@ -0,0 +1,118 @@
+/*
+ *  linux/fs/binfmt_elks.c
+ *
+ *  Copyright (C) 1996  Martin von Löwis
+ *  original #!-checking implemented by tytso.
+ *  ELKS hack added by Chad Page...
+ *  Cleaned up some more by Robert de Bath 
+ *                            I can't make it work with 1.2.13 tho! :-(
+ */
+
+#include <linux/module.h>
+#ifndef LINUX_VERSION_CODE
+#include <linux/version.h>
+#endif
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/malloc.h>
+#include <linux/binfmts.h>
+
+static int do_load_elksaout(struct linux_binprm *bprm,struct pt_regs *regs)
+{
+	char *cp, *interp, *i_name, *i_arg;
+	int retval;
+
+	/* What a horrible hack! :-) */
+	if ((bprm->buf[0] != 1)    || (bprm->buf[1] != 3) || 
+	    (bprm->buf[2] != 0x20) || (bprm->buf[3] != 4) ||
+	    bprm->sh_bang)
+		return -ENOEXEC;
+
+	bprm->sh_bang++;
+	iput(bprm->inode);
+#if LINUX_VERSION_CODE >= 0x010300
+	bprm->dont_iput=1;
+#endif
+
+	interp = "/lib/elksemu";
+	i_name = interp;
+	i_arg = 0;
+
+	for (cp=i_name; *cp && (*cp != ' ') && (*cp != '\t'); cp++) {
+ 		if (*cp == '/')
+			i_name = cp+1;
+	}
+
+	/*
+	 * OK, we've parsed out the interpreter name and
+	 * (optional) argument.
+	 * Splice in (1) the interpreter's name for argv[0]
+	 *           (2) (optional) argument to interpreter
+	 *           (3) filename of shell script (replace argv[0])
+	 *
+	 * This is done in reverse order, because of how the
+	 * user environment and arguments are stored.
+	 */
+	remove_arg_zero(bprm);
+	bprm->p = copy_strings(1, &bprm->filename, bprm->page, bprm->p, 2);
+	bprm->argc++;
+	if (i_arg) {
+		bprm->p = copy_strings(1, &i_arg, bprm->page, bprm->p, 2);
+		bprm->argc++;
+	}
+	bprm->p = copy_strings(1, &i_name, bprm->page, bprm->p, 2);
+	bprm->argc++;
+	if (!bprm->p) 
+		return -E2BIG;
+	/*
+	 * OK, now restart the process with the interpreter's inode.
+	 * Note that we use open_namei() as the name is now in kernel
+	 * space, and we don't need to copy it.
+	 */
+	retval = open_namei(interp, 0, 0, &bprm->inode, NULL);
+	if (retval)
+		return retval;
+#if LINUX_VERSION_CODE >= 0x010300
+	bprm->dont_iput=0;
+#endif
+	retval=prepare_binprm(bprm);
+	if(retval<0)
+		return retval;
+	return search_binary_handler(bprm,regs);
+}
+
+static int load_elksaout(struct linux_binprm *bprm,struct pt_regs *regs)
+{
+	int retval;
+	MOD_INC_USE_COUNT;
+	retval = do_load_elksaout(bprm,regs);
+	MOD_DEC_USE_COUNT;
+	return retval;
+}
+
+struct linux_binfmt elksaout_format = {
+#ifndef MODULE
+	NULL, 0, load_elksaout, NULL, NULL
+#else
+	NULL, &mod_use_count_, load_elksaout, NULL, NULL
+#endif
+};
+
+int init_elksaout_binfmt(void) {
+	return register_binfmt(&elksaout_format);
+}
+
+#ifdef MODULE
+#if LINUX_VERSION_CODE < 0x010300
+#include <linux/version.h>
+char kernel_version[] = UTS_RELEASE;
+#endif
+int init_module(void)
+{
+	return init_elksaout_binfmt();
+}
+
+void cleanup_module( void) {
+	unregister_binfmt(&elksaout_format);
+}
+#endif
diff --git a/elksemu/elks.c b/elksemu/elks.c
index f84c994..10d9d78 100644
--- a/elksemu/elks.c
+++ b/elksemu/elks.c
@@ -21,8 +21,11 @@
 volatile struct vm86_struct elks_cpu;
 unsigned char *elks_base;	/* Paragraph aligned */
 
+#ifdef DEBUG
 #define dbprintf(x) db_printf x
-/**/
+#else
+#define dbprintf(x) 
+#endif
 
 static void elks_init()
 {
@@ -195,12 +198,36 @@ void build_stack(char ** argv, char ** envp)
 void main(int argc, char *argv[], char *envp[])
 {
 	int fd;
-	dbprintf(("ELKSEMU 0.01 Alpha\n"));
-	if(argc==1)
+	struct stat st;
+	int ruid, euid, rgid, egid;
+
+	if(argc<=1)
 	{
 		fprintf(stderr,"elksemu cmd args.....\n");
 		exit(1);
 	}
+	/* This uses the _real_ user ID If the file is exec only that's */
+	/* ok cause the suid root will override.  */
+
+	if( access(argv[1], X_OK) < 0
+	  || stat(argv[1], &st) < 0
+	  || (fd=open(argv[1], O_RDONLY)) < 0)
+	{
+		perror(argv[1]);
+		exit(1);
+	}
+
+	/* Check the suid bits ... */
+	ruid = getuid(); rgid = getgid();
+	euid = ruid; egid = rgid;
+	if( st.st_mode & S_ISUID ) euid = st.st_uid;
+	if( st.st_mode & S_ISGID ) egid = st.st_gid;
+
+	/* Set the _real_ permissions, or revoke superuser priviliages */
+	setregid(rgid, egid);
+	setreuid(ruid, euid);
+
+	dbprintf(("ELKSEMU 0.0.6 Alpha\n"));
 	elks_init();
 
 	/* The Linux vm will deal with not allocating the unused pages */
@@ -219,12 +246,6 @@ void main(int argc, char *argv[], char *envp[])
 		fprintf(stderr, "Elks memory is at an illegal address\n");
 		exit(255);
 	}
-	fd=open(argv[1], O_RDONLY);
-	if(fd==-1)
-	{
-		perror(argv[1]);
-		exit(1);
-	}
 	
 	if(load_elks(fd) < 0)
 	{
@@ -240,6 +261,7 @@ void main(int argc, char *argv[], char *envp[])
 		run_elks();
 }
 
+#ifdef DEBUG
 void db_printf(const char * fmt, ...)
 {
 static FILE * db_fd = 0;
@@ -256,3 +278,4 @@ static FILE * db_fd = 0;
   rv = vfprintf(db_fd,fmt,ptr);
   va_end(ptr);
 }
+#endif
diff --git a/elksemu/elks_signal.c b/elksemu/elks_signal.c
index 2bf1e55..4b8e0c5 100644
--- a/elksemu/elks_signal.c
+++ b/elksemu/elks_signal.c
@@ -22,15 +22,17 @@ void sig_trap(int signo)
 
 int elks_signal(int bx,int cx,int dx,int di,int si)
 {
-   int rv;
+   void (*oldsig)(int) = 0;
    if( bx < 0 || bx >= NSIG ) { errno = EINVAL; return -1; }
-   if( cx == 0 )      rv = (signal(bx, SIG_DFL) == SIG_ERR);
-   else if( cx == 1 ) rv = (signal(bx, SIG_IGN) == SIG_ERR);
+   if( cx == 0 )      oldsig = signal(bx, SIG_DFL);
+   else if( cx == 1 ) oldsig = signal(bx, SIG_IGN);
    else 
    {
       elks_sigtrap = cx;
-      rv = (signal(bx, sig_trap) == SIG_ERR);
+      oldsig = signal(bx, sig_trap);
    }
-
-   return -rv;
+   if( oldsig == SIG_ERR) return -1;
+   if( oldsig == SIG_DFL) return 0;
+   if( oldsig == SIG_IGN) return 1;
+   return 2;
 }
diff --git a/elksemu/elks_sys.c b/elksemu/elks_sys.c
index 7ca946c..586ee9b 100644
--- a/elksemu/elks_sys.c
+++ b/elksemu/elks_sys.c
@@ -22,7 +22,11 @@
 #include <dirent.h>
 #include "elks.h" 
 
+#ifdef DEBUG
 #define dbprintf(x) db_printf x
+#else
+#define dbprintf(x)
+#endif
 
 #define sys_signal elks_signal
 extern int elks_signal(int bx,int cx,int dx,int di,int si);