bugfixes

1 files changed, 787 insertions, 0 deletions

diff --git a/kernel/redir_hack.c b/kernel/redir_hack.c
new file mode 100644
index 0000000..4c91a4f
--- /dev/null
+++ b/kernel/redir_hack.c
@@ -0,0 +1,787 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/unistd.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/smp_lock.h>
+#include <asm/uaccess.h>
+#include <linux/coda_psdev.h>
+#include <linux/version.h>
+
+#if 0
+#define DEB(X) printk X
+#else
+#define DEB(X)
+#endif
+
+#define REDIR_VERSION "0.3"
+
+extern void *sys_call_table[];
+
+typedef asmlinkage int (*chdir_func)    (const char *);
+typedef asmlinkage int (*stat_func)     (const char *, struct stat *);
+typedef asmlinkage int (*access_func)   (const char *, int);
+typedef asmlinkage int (*open_func)     (const char *, int, int);
+typedef asmlinkage int (*readlink_func) (const char *, char *, int);
+typedef asmlinkage int (*getcwd_func)   (char *, unsigned long);
+
+static chdir_func    orig_chdir;
+static stat_func     orig_stat;
+static stat_func     orig_lstat;
+static access_func   orig_access;
+static open_func     orig_open;
+static readlink_func orig_readlink;
+static getcwd_func   orig_getcwd;
+
+typedef asmlinkage long (*stat64_func)   (const char *, struct stat64 *, long);
+
+static stat64_func   orig_stat64;
+static stat64_func   orig_lstat64;
+
+#ifdef __i386__
+typedef asmlinkage int (*execve_func) (struct pt_regs);
+
+static execve_func orig_execve;
+#endif
+
+#define AVFS_MAGIC_CHAR '#'
+
+#define PF_AVFS 0x00008000
+
+#define OVERLAY_BASE "/mnt/tmp"
+
+#define path_ok(pwd) (pwd->d_parent == pwd || !list_empty(&pwd->d_hash))
+
+static char *path_pwd(char *page)
+{
+        return d_path(current->fs->pwd, current->fs->pwdmnt, page, PAGE_SIZE);
+}
+
+static int a_path_walk(const char *pathname, int flags, struct nameidata *nd)
+{
+        int error;
+
+        error = 0;
+        if (path_init(pathname, flags, nd))
+                error = path_walk(pathname, nd);
+
+        return error;
+}
+
+static void a_path_release(struct nameidata *nd)
+{
+        dput(nd->dentry);
+        mntput(nd->mnt);
+}
+
+static char *resolv_virt(const char *pathname, int must_exist, int flags)
+{
+        struct nameidata root;
+	struct nameidata nd;
+        struct dentry *origroot;
+        struct vfsmount *origrootmnt;
+	char *newpathname = NULL;
+	char *page = NULL;
+	char *path = NULL;
+	int pathlen = 0;
+        int error;
+        int newflags;
+        char overlay_dir[128];
+        unsigned overlay_dir_len;
+        
+        sprintf(overlay_dir, "%s/%u", OVERLAY_BASE, current->fsuid);
+        overlay_dir_len = strlen(overlay_dir);
+        
+	lock_kernel();
+
+	DEB((KERN_INFO "resolve_virt pathname: '%s'\n", 
+	       pathname ? pathname : "(null)"));
+
+        error = a_path_walk(overlay_dir, LOOKUP_POSITIVE|LOOKUP_FOLLOW, &root);
+        if(error)
+            goto out;
+
+	origroot = current->fs->root;
+        origrootmnt = current->fs->rootmnt;
+
+	current->fs->root = root.dentry;
+        current->fs->rootmnt = root.mnt;
+	
+        newflags = flags;
+        if(must_exist)
+                newflags |= LOOKUP_POSITIVE;
+
+        error  = a_path_walk(pathname, newflags, &nd);
+	if(!error) {
+		if(path_ok(nd.dentry)) {
+			page = (char *) __get_free_page(GFP_USER);
+			if(page) {
+				path = d_path(nd.dentry, nd.mnt, page,
+                                              PAGE_SIZE);
+				DEB((KERN_INFO "resolve_virt path = '%s'\n",
+				     path));
+				pathlen = (unsigned int) page + PAGE_SIZE - 
+					(unsigned int) path;
+			}
+		}
+                a_path_release(&nd);
+	}
+
+	current->fs->root = origroot;
+        current->fs->rootmnt = origrootmnt;
+
+        a_path_release(&root);
+
+	if(path) {
+		int isvirtual;
+
+                error  = a_path_walk(path, flags, &nd);
+		if(!error) {
+			if(nd.dentry->d_inode)
+				isvirtual = 0;
+			else if(must_exist)
+				isvirtual = 1;
+			else if(strchr(path, AVFS_MAGIC_CHAR))
+				isvirtual = 1;
+			else 
+				isvirtual = 0;
+
+                        a_path_release(&nd);
+		}
+		else {
+			isvirtual = 1;
+		}
+
+		if(!isvirtual) {
+			newpathname = kmalloc(pathlen + 1, GFP_USER);
+			if(newpathname)
+				strncpy(newpathname, path, pathlen);
+		}
+		else {
+			newpathname = kmalloc(overlay_dir_len + pathlen + 1,
+					      GFP_USER);
+
+			if(newpathname) {
+				strcpy(newpathname, overlay_dir);
+				strncat(newpathname, path, pathlen);
+			}
+		}
+	}
+
+	if(page)
+		free_page((unsigned long) page);
+
+
+	DEB((KERN_INFO "resolve_virt newpathname: '%s'\n", 
+	     newpathname ? newpathname : "(null)"));
+
+  out:
+	unlock_kernel();
+	return newpathname;
+}
+
+
+#define FUSE_SUPER_MAGIC 0x65735546
+
+#define cwd_virtual() \
+	(current->fs->pwd->d_sb->s_magic == FUSE_SUPER_MAGIC)
+
+static char *get_abs_path(const char *filename)
+{
+	char *cwd;
+	int cwdlen, fnamelen;
+	char *abspath, *s;
+	char *page;
+        char overlay_dir[128];
+        unsigned overlay_dir_len;
+        
+        sprintf(overlay_dir, "/mnt/avfs/%010u", current->fsuid);
+        overlay_dir_len = strlen(overlay_dir);
+
+        if(!path_ok(current->fs->pwd))
+                return NULL;
+
+        page = (char *) __get_free_page(GFP_USER);
+	if(!page)
+		return NULL;
+
+        cwd = path_pwd(page);
+	cwdlen = (unsigned int) page + PAGE_SIZE - (unsigned int) cwd - 1;
+	if(cwd_virtual() && cwdlen > overlay_dir_len) {
+		cwd += overlay_dir_len;
+		cwdlen -= overlay_dir_len;
+	}
+		
+
+	fnamelen = strlen(filename);
+
+	abspath = kmalloc(cwdlen + 1 + fnamelen + 1, GFP_USER);
+	if(abspath) {
+		s = abspath;
+		strncpy(s, cwd, cwdlen);
+		s += cwdlen;
+		*s++ = '/';
+		strncpy(s, filename, fnamelen + 1);
+	}
+	free_page((unsigned long) page);
+	
+	return abspath;
+}
+
+static char *resolve_name(const char *kfilename, int must_exist, int flags)
+{
+	char *tmp;
+	char *newfilename;		
+
+	tmp = getname(kfilename);
+	if(IS_ERR(tmp))
+		return tmp;
+
+
+	if((tmp[0] != '/' && cwd_virtual()) || strchr(tmp, AVFS_MAGIC_CHAR)) {
+		DEB((KERN_INFO "resolve_name: %s (%i/%s)\n", tmp, 
+		     current->pid,
+		     (current->flags & PF_AVFS) ? "on" : "off"));
+
+		if(strcmp(tmp, "/#avfs-on") == 0) {
+			printk(KERN_INFO "AVFS ON  (pid: %i)\n",
+			       current->pid);
+			current->flags |= PF_AVFS;
+			newfilename = ERR_PTR(-EEXIST);
+		}
+		else if(!(current->flags & PF_AVFS))
+			newfilename = NULL;
+		else if(strcmp(tmp, "/#avfs-off") == 0) {
+			printk(KERN_INFO "AVFS OFF (pid: %i)\n",
+			       current->pid);
+			current->flags &= ~PF_AVFS;
+			newfilename = ERR_PTR(-EEXIST);
+		}
+		else {
+			if(tmp[0] == '/') {
+				newfilename = resolv_virt(tmp, must_exist, flags);
+			}
+			else {
+				char *abspath;
+
+				abspath = get_abs_path(tmp);
+				if(abspath) {
+					newfilename = resolv_virt(abspath, must_exist, flags);
+					kfree(abspath);
+				}
+				else
+					newfilename = NULL;
+			}
+		}
+	}
+	else 
+		newfilename = NULL;
+	
+	putname(tmp);
+	
+	return newfilename;
+}
+
+asmlinkage int virt_chdir(const char *filename)
+{
+	int ret;
+	mm_segment_t old_fs;
+	char *newfilename;
+	
+	if(!cwd_virtual()) {
+		ret = (*orig_chdir)(filename);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_chdir)(filename);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+
+	DEB((KERN_INFO "CHDIR: trying '%s'\n", newfilename));
+		
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret =  (*orig_chdir)(newfilename);
+	set_fs(old_fs);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "CHDIR: result %i\n", ret));
+	
+	return ret;
+}
+
+static int do_orig_stat(stat_func sfunc, const char *filename,
+			struct stat *statbuf)
+{
+	int ret;
+	mm_segment_t old_fs;
+	struct stat locbuf;
+
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret =  (*sfunc)(filename, &locbuf);
+	set_fs(old_fs);
+
+	if(ret == 0)
+		ret = (copy_to_user(statbuf, &locbuf, sizeof(locbuf)) ? 
+		       -EFAULT : 0);
+
+	return ret;
+}
+
+asmlinkage int virt_stat(const char *filename, struct stat *statbuf)
+{
+	int ret;
+	char *newfilename;
+
+	if(!cwd_virtual()) {
+		ret = (*orig_stat)(filename, statbuf);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_stat)(filename, statbuf);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "STAT: trying '%s'\n", newfilename));
+
+	ret = do_orig_stat(orig_stat, newfilename, statbuf);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "STAT: result %i\n", ret));
+
+	return ret;
+}
+
+asmlinkage int virt_lstat(const char *filename, struct stat *statbuf)
+{
+	int ret;
+	char *newfilename;
+
+	if(!cwd_virtual()) {
+		ret = (*orig_lstat)(filename, statbuf);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 0);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_lstat)(filename, statbuf);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "LSTAT: trying '%s'\n", newfilename));
+
+	ret = do_orig_stat(orig_lstat, newfilename, statbuf);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "LSTAT: result %i\n", ret));
+
+	return ret;
+}
+
+
+asmlinkage int virt_access(const char *filename, int mode)
+{
+	int ret;
+	mm_segment_t old_fs;
+	char *newfilename;
+	
+	if(!cwd_virtual()) {
+		ret = (*orig_access)(filename, mode);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_access)(filename, mode);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "ACCESS: trying '%s'\n", newfilename));
+		
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret = (*orig_access)(newfilename, mode);
+	set_fs(old_fs);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "ACCESS: result %i\n", ret));
+	
+	return ret;
+}
+
+asmlinkage int virt_open(const char *filename, int flags, int mode)
+{
+	int ret;
+	mm_segment_t old_fs;
+	char *newfilename;
+	
+	if(!cwd_virtual()) {
+		ret = (*orig_open)(filename, flags, mode);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_open)(filename, flags, mode);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "OPEN: trying '%s'\n", newfilename));
+		
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret = (*orig_open)(newfilename, flags, mode);
+	set_fs(old_fs);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "OPEN: result %i\n", ret));
+	
+	return ret;
+}
+
+asmlinkage int virt_readlink(const char *filename, char *buf, int bufsiz)
+{
+	int ret;
+	mm_segment_t old_fs;
+	char *newfilename;
+	char *locbuf;
+	int len;
+	
+	if(!cwd_virtual()) {
+		ret = (*orig_readlink)(filename, buf, bufsiz);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 0);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_readlink)(filename, buf, bufsiz);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "READLINK: trying '%s'\n", newfilename));
+
+	/* bufsiz is legal (already checked by sys_readlink) */
+	len = bufsiz;
+	if(bufsiz > PAGE_SIZE)
+		len = PAGE_SIZE;
+			
+	locbuf = (char *) __get_free_page(GFP_USER);
+			
+	ret = -ENOMEM;
+	if(locbuf) {
+		old_fs = get_fs();
+		set_fs(get_ds());
+		ret =  (*orig_readlink)(newfilename, locbuf, len);
+		set_fs(old_fs);
+
+		if(ret >= 0)
+			if(copy_to_user(buf, locbuf, len))
+				ret = -EFAULT;
+		free_page((unsigned long) locbuf);
+	}
+	kfree(newfilename);
+
+	DEB((KERN_INFO "READLINK: result %i\n", ret));
+	
+	return ret;
+}
+
+asmlinkage int virt_getcwd(char *buf, unsigned long size)
+{
+	int ret;
+	char *cwd;
+	unsigned long cwdlen;
+	char *page;
+	char *newcwd;
+	unsigned long newlen;
+        char overlay_dir[128];
+        unsigned overlay_dir_len;
+        	
+	ret = (*orig_getcwd)(buf, size);
+
+	if(!cwd_virtual() || ret < 0)
+		return ret;
+		
+	if(!path_ok(current->fs->pwd))
+		return -ENOENT;
+	
+	page = (char *) __get_free_page(GFP_USER);
+	if(!page)
+		return -ENOMEM;
+	
+        cwd = path_pwd(page);
+	cwdlen = PAGE_SIZE + (page - cwd) - 1;
+	
+        sprintf(overlay_dir, "/mnt/avfs/%010u", current->fsuid);
+        overlay_dir_len = strlen(overlay_dir);
+
+	if(cwdlen >= overlay_dir_len && 
+	   strncmp(cwd, overlay_dir, overlay_dir_len) == 0) {
+		if(cwdlen == overlay_dir_len) {
+			newcwd = "/";
+			newlen = 1;
+		}
+		else {
+			newcwd = cwd + overlay_dir_len;
+			newlen = cwdlen - overlay_dir_len;
+		}
+
+		ret = -ERANGE;
+		if(newlen + 1 <= size) {
+			ret = newlen + 1;
+			if(copy_to_user(buf, newcwd, newlen + 1))
+				ret = -EFAULT;
+		}
+	}
+	free_page((unsigned long) page);
+
+	return ret;
+}
+
+
+static long do_orig_stat64(stat64_func sfunc, const char *filename,
+			  struct stat64 * statbuf, long flags)
+{
+	long ret;
+	mm_segment_t old_fs;
+	struct stat64 locbuf;
+
+	old_fs = get_fs();
+	set_fs(get_ds());
+	ret =  (*sfunc)(filename, &locbuf, flags);
+	set_fs(old_fs);
+
+	if(ret == 0)
+		ret = (copy_to_user(statbuf, &locbuf, sizeof(locbuf)) ? 
+		       -EFAULT : 0);
+
+	return ret;
+}
+
+asmlinkage long virt_stat64(char * filename, struct stat64 * statbuf, long flags)
+{
+	long ret;
+	char *newfilename;
+
+	if(!cwd_virtual()) {
+		ret = (*orig_stat64)(filename, statbuf, flags);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_stat64)(filename, statbuf, flags);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "STAT64: trying '%s'\n", newfilename));
+
+	ret = do_orig_stat64(orig_stat64, newfilename, statbuf, flags);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "STAT64: result %li\n", ret));
+
+	return ret;
+}
+
+asmlinkage long virt_lstat64(char * filename, struct stat64 * statbuf, long flags)
+{
+	long ret;
+	char *newfilename;
+
+	if(!cwd_virtual()) {
+		ret = (*orig_lstat64)(filename, statbuf, flags);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 0);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return (*orig_lstat64)(filename, statbuf, flags);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "LSTAT64: trying '%s'\n", newfilename));
+
+	ret = do_orig_stat64(orig_lstat64, newfilename, statbuf, flags);
+	kfree(newfilename);
+
+	DEB((KERN_INFO "LSTAT64: result %li\n", ret));
+
+	return ret;
+}
+
+#ifdef __i386__
+
+asmlinkage int real_execve(struct pt_regs *regs)
+{
+	int error;
+	char * filename;
+
+	filename = getname((char *) regs->ebx);
+	error = PTR_ERR(filename);
+	if (IS_ERR(filename))
+		goto out;
+	error = do_execve(filename, (char **) regs->ecx, (char **) regs->edx, regs);
+	if (error == 0)
+		current->ptrace &= ~PT_DTRACE;
+	putname(filename);
+
+out:
+	return error;
+}
+
+asmlinkage int virt_execve(struct pt_regs regs)
+{
+	int ret;
+	char *newfilename;
+	char *filename = (char *) regs.ebx;
+
+	if(!cwd_virtual()) {
+		ret = real_execve(&regs);
+		if(ret != -ENOENT) 
+			return ret;
+	}
+	else 
+		ret = 0;
+
+	newfilename = resolve_name(filename, 1, 1);
+	if(!newfilename) {
+		if(ret)
+			return ret;
+		else
+			return real_execve(&regs);
+	}
+	if(IS_ERR(newfilename))
+			return PTR_ERR(newfilename);
+
+	DEB((KERN_INFO "EXECVE: trying '%s'\n", newfilename));
+
+	ret = do_execve(newfilename, (char **) regs.ecx, (char **) regs.edx,
+			&regs);
+	if (ret == 0)
+		current->ptrace &= ~PT_DTRACE;
+	kfree(newfilename);
+
+	DEB((KERN_INFO "EXECVE: result %i\n", ret));
+
+	return ret;
+}
+#endif /* __i386__ */
+
+void *replace_syscall(int index, void *new_syscall)
+{
+	void *orig_syscall = sys_call_table[index];
+
+	printk(KERN_INFO "replacing syscall nr. %3i [%p] with [%p]\n", 
+	       index, orig_syscall, new_syscall);
+	sys_call_table[index] = new_syscall;
+	
+	return orig_syscall;
+}
+
+int init_module(void)
+{
+    printk(KERN_INFO "redir init (version %s)\n", REDIR_VERSION);
+
+    orig_chdir    = replace_syscall(__NR_chdir,    virt_chdir);
+    orig_stat     = replace_syscall(__NR_stat,     virt_stat);
+    orig_lstat    = replace_syscall(__NR_lstat,    virt_lstat);
+    orig_access   = replace_syscall(__NR_access,   virt_access);
+    orig_open     = replace_syscall(__NR_open,     virt_open);
+    orig_readlink = replace_syscall(__NR_readlink, virt_readlink);
+    orig_getcwd   = replace_syscall(__NR_getcwd,   virt_getcwd);
+
+    orig_stat64   = replace_syscall(__NR_stat64,   virt_stat64);
+    orig_lstat64  = replace_syscall(__NR_lstat64,  virt_lstat64);
+
+#ifdef __i386__
+    orig_execve   = replace_syscall(__NR_execve,   virt_execve);
+#endif
+
+    return 0;
+}
+
+
+void cleanup_module(void)
+{
+    printk(KERN_INFO "redir cleanup\n");
+   
+    replace_syscall(__NR_chdir,    orig_chdir);
+    replace_syscall(__NR_stat,     orig_stat);
+    replace_syscall(__NR_lstat,    orig_lstat);
+    replace_syscall(__NR_access,   orig_access);
+    replace_syscall(__NR_open,     orig_open);
+    replace_syscall(__NR_readlink, orig_readlink);
+    replace_syscall(__NR_getcwd,   orig_getcwd);
+
+    replace_syscall(__NR_stat64,   orig_stat64);
+    replace_syscall(__NR_lstat64,  orig_lstat64);
+
+#ifdef __i386__
+    replace_syscall(__NR_execve,   orig_execve);
+#endif
+
+}