Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934063AbXJRP6e (ORCPT ); Thu, 18 Oct 2007 11:58:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1765436AbXJRP43 (ORCPT ); Thu, 18 Oct 2007 11:56:29 -0400 Received: from services.sin.cvut.cz ([147.32.110.2]:60461 "EHLO services.sin.cvut.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763519AbXJRP4R (ORCPT ); Thu, 18 Oct 2007 11:56:17 -0400 From: Jaroslav Sykora Reply-To: jaroslav.sykora@gmail.com To: linux-kernel@vger.kernel.org Subject: [RFC PATCH 2/5] Shadow directories: core Date: Thu, 18 Oct 2007 17:23:59 +0200 User-Agent: KMail/1.9.7 References: <200710181721.09201.jara@sin.cvut.cz> In-Reply-To: <200710181721.09201.jara@sin.cvut.cz> X-Face: >I|[{8s3:Ic!^A\YY'ktAfvq]K.-@B=!>(:.VX7_KNlZ@`l)vxL}2g~)k(#@=?utf-8?q?BN=24U+3MgB2=0A=097yR=5D=26tZ8PTc=3D=60?=ZZB_o Cc: linux-fsdevel@vger.kernel.org MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200710181723.59193.jara@sin.cvut.cz> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 23370 Lines: 896 Implements two stage lookup with escape character filtering and system calls for i386. Changes lookup path, namely do_path_lookup. This function is split into path_lookup_norm(), which performs standard name lookup, and path_lookup_shdw(), which performs name lookup in an associated shadow directory. Signed-off-by: Jaroslav Sykora arch/i386/kernel/syscall_table.S | 6 fs/exec.c | 4 fs/file_table.c | 19 fs/namei.c | 610 ++++++++++++++++++++++++++++- fs/namespace.c | 13 include/linux/syscalls.h | 6 kernel/exit.c | 8 kernel/fork.c | 20 8 files changed, 672 insertions(+), 14 deletions(-) --- orig/fs/namei.c 2007-10-07 19:00:19.000000000 +0200 +++ new/fs/namei.c 2007-10-18 15:35:54.000000000 +0200 @@ -31,6 +31,7 @@ #include #include #include +#include #include #include @@ -515,6 +516,25 @@ static struct dentry * real_lookup(struc return result; } +static inline int use_shadow(struct fs_struct *fs, struct nameidata *nd) +{ + /* assert: fs->lock held */ + return (fs->flags & SHDW_ENABLED) && (nd->flags & LOOKUP_INSHDW); +} + +static inline struct dentry *fs_root(struct fs_struct *fs, struct nameidata *nd) +{ + /* assert: current->fs->lock held */ + return (use_shadow(fs, nd)) ? fs->shdwroot : fs->root; +} + +static inline struct vfsmount *fs_rootmnt(struct fs_struct *fs, + struct nameidata *nd) +{ + /* assert: current->fs->lock held */ + return (use_shadow(fs, nd)) ? fs->shdwrootmnt : fs->rootmnt; +} + static int __emul_lookup_dentry(const char *, struct nameidata *); /* SMP-safe */ @@ -532,8 +552,8 @@ walk_init_root(const char *name, struct return 0; read_lock(&fs->lock); } - nd->mnt = mntget(fs->rootmnt); - nd->dentry = dget(fs->root); + nd->mnt = mntget(fs_rootmnt(fs, nd)); + nd->dentry = dget(fs_root(fs, nd)); read_unlock(&fs->lock); return 1; } @@ -730,9 +750,9 @@ static __always_inline void follow_dotdo struct vfsmount *parent; struct dentry *old = nd->dentry; - read_lock(&fs->lock); - if (nd->dentry == fs->root && - nd->mnt == fs->rootmnt) { + read_lock(&fs->lock); + if (nd->dentry == fs_root(fs, nd) && + nd->mnt == fs_rootmnt(fs, nd)) { read_unlock(&fs->lock); break; } @@ -842,6 +862,11 @@ static fastcall int __link_path_walk(con hash = init_name_hash(); do { + if (unlikely((nd->flags & LOOKUP_FINDCHAR) && + (c == nd->find_char))) { + /* shadow control char found */ + nd->flags |= LOOKUP_CHARFOUND; + } name++; hash = partial_name_hash(c, hash); c = *(const unsigned char *)name; @@ -1100,8 +1125,8 @@ set_it: } } -/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ -static int fastcall do_path_lookup(int dfd, const char *name, +/* Lookup @name, starting at @dfd, use normal (non-shadow) root and pwd */ +static int fastcall path_lookup_norm(int dfd, const char *name, unsigned int flags, struct nameidata *nd) { int retval = 0; @@ -1168,6 +1193,313 @@ fput_fail: goto out_fail; } +/* + * Set @filp->f_shdw, @filp->f_shdwmnt to @mnt,@dentry. + * Takes @filp->f_owner->lock. + * Note: if @dentry == NULL then @mnt may be ERR_PTR(-EINVAL). + */ +static void set_fileshdw(struct file *filp, struct vfsmount *mnt, + struct dentry *dentry) +{ + struct dentry *old_dentry; + struct vfsmount *old_mnt; + + BUG_ON(dentry != NULL && mnt == NULL); + write_lock(&filp->f_owner.lock); + old_dentry = filp->f_shdw; + old_mnt = filp->f_shdwmnt; + filp->f_shdw = dget(dentry); + if (dentry) + filp->f_shdwmnt = mntget(mnt); + else + /* mnt is ERR_PTR */ + filp->f_shdwmnt = mnt; + write_unlock(&filp->f_owner.lock); + + if (old_dentry) { + dput(old_dentry); + mntput(old_mnt); + } +} + +/* + * Determine @filp->f_shdw,f_shdwmnt from @filp->dentry,mnt + * and current->fs->shdwroot. + * Also check whether it's a directory and we have permisson. + * Called only from get_file_shdwdir(). + */ +static int validate_shdwfile(struct file *filp) +{ + struct nameidata nd; + char *buf, *name; + int res = -ENOMEM; + + buf = (char *)__get_free_page(GFP_KERNEL); + if (!buf) + goto fail; + + /* doesn't need a lock for reading f_dentry, f_vfsmnt */ + name = d_path(filp->f_dentry, filp->f_vfsmnt, buf, PAGE_SIZE); + res = PTR_ERR(name); + if (IS_ERR(name)) + goto fail_free; + + BUG_ON(*name != '/'); + res = path_lookup_shdw(AT_FDCWD, name, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); + if (res) + goto fail_free; + + res = permission(nd.dentry->d_inode, MAY_EXEC, NULL); + if (res) + goto fail_put; + + /* ok -> valid */ + set_fileshdw(filp, nd.mnt, nd.dentry); + path_release(&nd); + free_page((unsigned long)buf); +out: + /* current->fs->lock is not held on exit */ + return res; + +fail_put: + path_release(&nd); +fail_free: + free_page((unsigned long)buf); +fail: + /* error -> invalid */ + set_fileshdw(filp, ERR_PTR(-EINVAL), NULL); + goto out; +} + +/* + * Set *@dentry,*@mnt to @file->f_shdw,f_shdwmnt, try to validate + * them if needed. + */ +int get_file_shdwdir(struct file *file, struct dentry **dentry, + struct vfsmount **mnt) +{ + int retval = -ENOENT; + + read_lock(&file->f_owner.lock); + while (!file->f_shdw) { + if (!file->f_shdwmnt) { + /* delayed, try to validate */ + read_unlock(&file->f_owner.lock); + if (validate_shdwfile(file)) + goto out; + /* ok but continue loop to avoid races */ + read_lock(&file->f_owner.lock); + } else + /* invalid */ + goto out_unlock; + /* continue loop to avoid races */ + } + /* get the shadow dir */ + *dentry = dget(file->f_shdw); + *mnt = mntget(file->f_shdwmnt); + retval = 0; +out_unlock: + read_unlock(&file->f_owner.lock); +out: + return retval; +} + +/* + * Determine current->fs->shdwpwd,shdwpwdmnt from current->fs->pwd,pwdmnt. + * Also check whether it's a directory and we have permisson. + */ +static int validate_shdwpwd(void) +{ + /* called with current->fs->lock held */ + struct dentry *pwd = dget(current->fs->pwd); + struct vfsmount *mnt = mntget(current->fs->pwdmnt); + struct nameidata nd; + char *buf, *name; + int res = -ENOMEM; + + read_unlock(¤t->fs->lock); + buf = (char *)__get_free_page(GFP_KERNEL); + if (!buf) + goto fail; + + name = d_path(pwd, mnt, buf, PAGE_SIZE); + res = PTR_ERR(name); + if (IS_ERR(name)) + goto fail_free; + + BUG_ON(*name != '/'); + /* won't recurse here because @name starts with '/' */ + res = path_lookup_shdw(AT_FDCWD, name, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); + if (res) + goto fail_free; + + res = permission(nd.dentry->d_inode, MAY_EXEC, NULL); + if (res) + goto fail_put; + + /* ok -> valid */ + set_fs_shdwpwd(current->fs, nd.mnt, nd.dentry); + path_release(&nd); + free_page((unsigned long)buf); +out: + dput(pwd); + mntput(mnt); + /* current->fs->lock is NOT held on exit */ + return res; + +fail_put: + path_release(&nd); +fail_free: + free_page((unsigned long)buf); +fail: + /* error -> invalidate */ + set_fs_shdwpwd(current->fs, ERR_PTR(-EINVAL), NULL); + goto out; +} + +/* + * Set *@dentry,*@mnt to current->fs->shdwpwd,shdwpwdmnt, try to validate + * them if needed. + */ +static int get_shdwpwd(struct dentry **dentry, struct vfsmount **mnt) +{ + int retval = -ENOENT; + /* assert: current->fs->lock is held */ + while (!current->fs->shdwpwd) { + if (current->fs->shdwpwdmnt) + /* ERR_PTR - invalid */ + goto out_unlock; + + /* it's delayed -> validate */ + if (validate_shdwpwd()) + /* (current->fs->lock is unlocked + * in validate_shdwpwd()) */ + goto out; + + read_lock(¤t->fs->lock); + /* continue loop to avoid races */ + } + + *mnt = mntget(current->fs->shdwpwdmnt); + *dentry = dget(current->fs->shdwpwd); + retval = 0; +out_unlock: + read_unlock(¤t->fs->lock); +out: + /* current->fs->lock is NOT held on exit */ + return retval; +} + +/* + * Lookup @name, starting at @dfd, use shadow root and pwd. + * Try to validate current->fs->shdwpwd/filp->f_shdwmnt if needed. + */ +int fastcall path_lookup_shdw(int dfd, const char *name, + unsigned int flags, struct nameidata *nd) +{ + int retval = -ENOENT; + + nd->last_type = LAST_ROOT; /* if there are only slashes... */ + nd->flags = flags | LOOKUP_INSHDW | LOOKUP_NOALT; + nd->depth = 0; + + read_lock(¤t->fs->lock); + if (!(current->fs->flags & SHDW_ENABLED)) + goto unlock_fail; + + if (*name == '/') { + /* start at the shadow root */ + if (!current->fs->shdwroot) + goto unlock_fail; + nd->mnt = mntget(current->fs->shdwrootmnt); + nd->dentry = dget(current->fs->shdwroot); + read_unlock(¤t->fs->lock); + } else if (dfd == AT_FDCWD) { + /* start at the shadow pwd */ + retval = get_shdwpwd(&nd->dentry, &nd->mnt); + /* current->fs->lock is not held here */ + if (retval) + goto out_fail; + } else { + int fput_needed; + struct file *file; + + read_unlock(¤t->fs->lock); + /* start at file's shadow dir */ + file = fget_light(dfd, &fput_needed); + retval = -EBADF; + if (!file) + goto out_fail; + + retval = get_file_shdwdir(file, &nd->dentry, &nd->mnt); + fput_light(file, fput_needed); + + if (retval) + goto out_fail; + } + + current->total_link_count = 0; + retval = link_path_walk(name, nd); + + if (likely(retval == 0)) { + if (unlikely(!audit_dummy_context() && nd && nd->dentry && + nd->dentry->d_inode)) + audit_inode(name, nd->dentry->d_inode); + } + +out_fail: + return retval; + +unlock_fail: + read_unlock(¤t->fs->lock); + goto out_fail; +} + +/* + * Perform full lookup of @name starting at @dfd. + * 1. do a normal lookup + * 2. if it fails try to lookup in shadow dir + * Returns 0 and nd will be valid on success; Retuns error, otherwise. + */ +static int fastcall do_path_lookup(int dfd, const char *name, + unsigned int flags, struct nameidata *nd) +{ + int retval; + + if (!(flags & LOOKUP_NOSHDW)) { + /* shadow dir isn't disabled in the current lookup session */ + read_lock(¤t->fs->lock); + if (current->fs->flags & SHDW_ENABLED) { + /* shadow is enabled */ + if (current->fs->flags & SHDW_USE_ESC) { + flags |= LOOKUP_FINDCHAR; + nd->find_char = current->fs->shdw_escch; + } + } else + /* shadow is disabled - disable it in lookup session */ + flags |= LOOKUP_NOSHDW; + read_unlock(¤t->fs->lock); + } + + retval = path_lookup_norm(dfd, name, flags, nd); + + /* + * Do another lookup in the shadow dir iff: + * normal lookup failed + * && shadow is enabled + * && the last lookup was not already going within shadows + * && user asked for the escape character and we found it + */ + if (unlikely(retval && !(nd->flags & (LOOKUP_NOSHDW|LOOKUP_INSHDW)) + && !((nd->flags & LOOKUP_FINDCHAR) + && !(nd->flags & LOOKUP_CHARFOUND)))) + retval = path_lookup_shdw(dfd, name, flags, nd); + + return retval; +} + int fastcall path_lookup(const char *name, unsigned int flags, struct nameidata *nd) { @@ -1225,6 +1557,16 @@ static int __path_lookup_intent_open(int } } else if (err != 0) release_open_intent(nd); + else if (!(nd->flags & LOOKUP_NOSHDW) && + S_ISDIR(nd->dentry->d_inode->i_mode)) { + /* setup file's shadow dir */ + /* default: filp->f_shdw = filp->f_shdwmnt = NULL */ + if (nd->flags & LOOKUP_INSHDW) { + filp->f_shdw = dget(nd->dentry); + filp->f_shdwmnt = mntget(nd->mnt); + } + } + return err; } @@ -2792,6 +3134,260 @@ const struct inode_operations page_symli .put_link = page_put_link, }; + +/* + * Find task by @pid, check permissions. + * @pid == 0 -> current. + */ +static struct task_struct *tsk_by_pid(pid_t pid) +{ + struct task_struct *tsk = current; + + if (pid) { + read_lock(&tasklist_lock); + tsk = find_task_by_pid(pid); + if (tsk) + get_task_struct(tsk); + read_unlock(&tasklist_lock); + if (!tsk) + tsk = ERR_PTR(-ESRCH); + else if (!ptrace_may_attach(tsk)) { + put_task_struct(tsk); + tsk = ERR_PTR(-EPERM); + } + } + return tsk; +} + +asmlinkage long sys_getshdwinfo(pid_t pid, int func, int __user *data) +{ + struct task_struct *tsk = tsk_by_pid(pid); + long ret = PTR_ERR(tsk); + + if (IS_ERR(tsk)) + goto out_noput; + ret = -EINVAL; + + switch (func) { + case FSI_SHDW_ENABLE: + read_lock(&tsk->fs->lock); + ret = (tsk->fs->flags & SHDW_ENABLED) ? 1 : 0; + read_unlock(&tsk->fs->lock); + ret = put_user(ret, data); + break; + + case FSI_SHDW_ESC_EN: + read_lock(&tsk->fs->lock); + ret = (tsk->fs->flags & SHDW_USE_ESC) ? 1 : 0; + read_unlock(&tsk->fs->lock); + ret = put_user(ret, data); + break; + + case FSI_SHDW_ESC_CHAR: + read_lock(&tsk->fs->lock); + ret = tsk->fs->shdw_escch; + read_unlock(&tsk->fs->lock); + ret = put_user((char)ret, (char __user *)data); + break; + } + + if (pid) + put_task_struct(tsk); +out_noput: + /* avoid REGPARM breakage on x86: */ + prevent_tail_call(ret); + return ret; +} + +/* + * Set fs->shdwpwd,shdwpwdmnt according to @pathname. + * @pathname is NOT looked up in shadow dir. + */ +static int do_setshdwpwd(struct fs_struct *fs, const char __user *pathname) +{ + struct nameidata nd; + int error = __user_walk(pathname, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOSHDW, &nd); + if (error) + goto out; + + error = vfs_permission(&nd, MAY_EXEC); + if (error) + goto dput_and_out; + + set_fs_shdwpwd(fs, nd.mnt, nd.dentry); + +dput_and_out: + path_release(&nd); +out: + return error; +} + +/* + * Set fs->shdwroot,shdwrootmnt according to @pathname. + * @pathname is NOT looked up in shadow dir. + * If @pathname == NULL then disable shadow dir. + */ +static int do_setshdwroot(struct fs_struct *fs, const char __user *pathname) +{ + struct dentry *old_dentry; + struct vfsmount *old_mnt; + struct nameidata nd; + int error = 0; + + if (pathname) { + error = __user_walk(pathname, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOSHDW, &nd); + if (error) + goto out; + + error = vfs_permission(&nd, MAY_EXEC); + if (error) + goto dput_and_out; + } else { + /* remove shadow root */ + nd.dentry = NULL; + nd.mnt = NULL; + } + + write_lock(&fs->lock); + old_dentry = fs->shdwroot; + old_mnt = fs->shdwrootmnt; + fs->shdwroot = dget(nd.dentry); + fs->shdwrootmnt = mntget(nd.mnt); + if (!nd.dentry) + /* disable shadow dir */ + fs->flags &= ~SHDW_ENABLED; + write_unlock(&fs->lock); + + dput(old_dentry); + mntput(old_mnt); + +dput_and_out: + path_release(&nd); +out: + return error; +} + +/* + * Set file->f_shdw,f_shdwmnt according to @pathname. + * @pathname is NOT looked up in shadow dir. + * If @pathname == NULL then set file->f_shdw,f_shdwmnt as delayed. + */ +static int do_setshdwfd(struct task_struct *tsk, int fd, + const char __user *pathname) +{ + struct nameidata nd; + struct file *filp = __fget(tsk->files, fd); + int error = 0; + + if (!filp) + return -EBADF; + + if (pathname) { + error = __user_walk(pathname, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_NOSHDW, &nd); + if (error) + goto out; + + error = vfs_permission(&nd, MAY_EXEC); + if (!error) { + set_fileshdw(filp, nd.mnt, nd.dentry); + path_release(&nd); + } + } else { + /* set delayed */ + set_fileshdw(filp, NULL, NULL); + } +out: + fput(filp); + return error; +} + +asmlinkage long sys_setshdwpath(pid_t pid, int fd, const char __user *path) +{ + struct task_struct *tsk = tsk_by_pid(pid); + long ret = PTR_ERR(tsk); + + if (IS_ERR(tsk)) + goto out_noput; + + ret = -EINVAL; + + if (fd >= 0) + /* a normal file's shadow */ + ret = do_setshdwfd(tsk, fd, path); + else if (fd == SHDW_FD_ROOT) + /* root shadow */ + ret = do_setshdwroot(tsk->fs, path); + else if (fd == SHDW_FD_PWD) { + /* pwd shadow */ + if (path) + ret = do_setshdwpwd(tsk->fs, path); + else { + /* set delayed */ + set_fs_shdwpwd(tsk->fs, NULL, NULL); + ret = 0; + } + } + + if (pid) + put_task_struct(tsk); +out_noput: + /* avoid REGPARM breakage on x86: */ + prevent_tail_call(ret); + return ret; +} + +asmlinkage long sys_setshdwinfo(pid_t pid, int func, int data) +{ + struct task_struct *tsk = tsk_by_pid(pid); + long ret = PTR_ERR(tsk); + + if (IS_ERR(tsk)) + goto out_noput; + + ret = -EINVAL; + switch (func) { + case FSI_SHDW_ENABLE: + ret = 0; + write_lock(&tsk->fs->lock); + tsk->fs->flags &= ~SHDW_ENABLED; + if (data) { + /* may enable shadow? */ + if (tsk->fs->shdwroot && tsk->fs->shdwrootmnt) + tsk->fs->flags |= SHDW_ENABLED; + else + ret = -EPERM; + } + write_unlock(&tsk->fs->lock); + break; + + case FSI_SHDW_ESC_EN: + ret = 0; + write_lock(&tsk->fs->lock); + tsk->fs->flags &= ~SHDW_USE_ESC; + if (data) + tsk->fs->flags |= SHDW_USE_ESC; + write_unlock(&tsk->fs->lock); + break; + + case FSI_SHDW_ESC_CHAR: + ret = 0; + write_lock(&tsk->fs->lock); + tsk->fs->shdw_escch = (unsigned char)data; + write_unlock(&tsk->fs->lock); + break; + } + + if (pid) + put_task_struct(tsk); +out_noput: + /* avoid REGPARM breakage on x86: */ + prevent_tail_call(ret); + return ret; +} + EXPORT_SYMBOL(__user_walk); EXPORT_SYMBOL(__user_walk_fd); EXPORT_SYMBOL(follow_down); --- orig/fs/exec.c 2007-10-07 19:00:18.000000000 +0200 +++ new/fs/exec.c 2007-10-07 19:53:16.000000000 +0200 @@ -1076,11 +1076,15 @@ int flush_old_exec(struct linux_binprm * if (bprm->e_uid != current->euid || bprm->e_gid != current->egid) { suid_keys(current); set_dumpable(current->mm, suid_dumpable); + /* switch off the shadow directories for a suid exec */ + current->fs->flags &= ~SHDW_ENABLED; current->pdeath_signal = 0; } else if (file_permission(bprm->file, MAY_READ) || (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) { suid_keys(current); set_dumpable(current->mm, suid_dumpable); + /* switch off the shadow directories for a suid exec */ + current->fs->flags &= ~SHDW_ENABLED; } /* An exec changes our domain. We are no longer part of the thread --- orig/fs/namespace.c 2007-10-07 19:00:19.000000000 +0200 +++ new/fs/namespace.c 2007-10-07 13:39:08.000000000 +0200 @@ -1448,6 +1448,7 @@ static struct mnt_namespace *dup_mnt_ns( { struct mnt_namespace *new_ns; struct vfsmount *rootmnt = NULL, *pwdmnt = NULL, *altrootmnt = NULL; + struct vfsmount *shdwrootmnt = NULL, *shdwpwdmnt = NULL; struct vfsmount *p, *q; new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL); @@ -1494,6 +1495,14 @@ static struct mnt_namespace *dup_mnt_ns( altrootmnt = p; fs->altrootmnt = mntget(q); } + if (p == fs->shdwrootmnt) { + shdwrootmnt = p; + fs->shdwrootmnt = mntget(q); + } + if (p == fs->shdwpwdmnt) { + shdwpwdmnt = p; + fs->shdwpwdmnt = mntget(q); + } } p = next_mnt(p, mnt_ns->root); q = next_mnt(q, new_ns->root); @@ -1506,6 +1515,10 @@ static struct mnt_namespace *dup_mnt_ns( mntput(pwdmnt); if (altrootmnt) mntput(altrootmnt); + if (shdwrootmnt) + mntput(shdwrootmnt); + if (shdwpwdmnt) + mntput(shdwpwdmnt); return new_ns; } --- orig/fs/file_table.c 2007-07-09 01:32:17.000000000 +0200 +++ new/fs/file_table.c 2007-10-07 13:39:08.000000000 +0200 @@ -151,8 +151,8 @@ EXPORT_SYMBOL(fput); */ void fastcall __fput(struct file *file) { - struct dentry *dentry = file->f_path.dentry; - struct vfsmount *mnt = file->f_path.mnt; + struct dentry *dentry = file->f_path.dentry, *s_dentry = file->f_shdw; + struct vfsmount *mnt = file->f_path.mnt, *s_mnt = file->f_shdwmnt; struct inode *inode = dentry->d_inode; might_sleep(); @@ -177,15 +177,21 @@ void fastcall __fput(struct file *file) file_kill(file); file->f_path.dentry = NULL; file->f_path.mnt = NULL; + file->f_shdw = NULL; + file->f_shdwmnt = NULL; file_free(file); dput(dentry); mntput(mnt); + if (s_dentry) { + /* NOTE: if s_dentry == NULL then s_mnt may be ERR_PTR */ + dput(s_dentry); + mntput(s_mnt); + } } -struct file fastcall *fget(unsigned int fd) +struct file fastcall *__fget(struct files_struct *files, unsigned int fd) { struct file *file; - struct files_struct *files = current->files; rcu_read_lock(); file = fcheck_files(files, fd); @@ -201,6 +207,11 @@ struct file fastcall *fget(unsigned int return file; } +struct file fastcall *fget(unsigned int fd) +{ + return __fget(current->files, fd); +} + EXPORT_SYMBOL(fget); /* --- orig/kernel/exit.c 2007-10-07 19:00:26.000000000 +0200 +++ new/kernel/exit.c 2007-10-07 13:39:08.000000000 +0200 @@ -522,6 +522,14 @@ static inline void __put_fs_struct(struc dput(fs->altroot); mntput(fs->altrootmnt); } + if (fs->shdwroot) { + dput(fs->shdwroot); + mntput(fs->shdwrootmnt); + } + if (fs->shdwpwd) { + dput(fs->shdwpwd); + mntput(fs->shdwpwdmnt); + } kmem_cache_free(fs_cachep, fs); } } --- orig/kernel/fork.c 2007-10-07 19:00:26.000000000 +0200 +++ new/kernel/fork.c 2007-10-07 13:39:08.000000000 +0200 @@ -586,6 +586,9 @@ static inline struct fs_struct *__copy_f fs->root = dget(old->root); fs->pwdmnt = mntget(old->pwdmnt); fs->pwd = dget(old->pwd); + fs->flags = old->flags; + fs->shdw_escch = old->shdw_escch; + if (old->altroot) { fs->altrootmnt = mntget(old->altrootmnt); fs->altroot = dget(old->altroot); @@ -593,6 +596,23 @@ static inline struct fs_struct *__copy_f fs->altrootmnt = NULL; fs->altroot = NULL; } + + if (old->shdwroot) { + fs->shdwrootmnt = mntget(old->shdwrootmnt); + fs->shdwroot = dget(old->shdwroot); + } else { + fs->shdwrootmnt = NULL; + fs->shdwroot = NULL; + } + + if (old->shdwpwd) { + fs->shdwpwdmnt = mntget(old->shdwpwdmnt); + fs->shdwpwd = dget(old->shdwpwd); + } else { + fs->shdwpwdmnt = NULL; + fs->shdwpwd = NULL; + } + read_unlock(&old->lock); } return fs; --- orig/include/linux/syscalls.h 2007-10-07 19:00:26.000000000 +0200 +++ new/include/linux/syscalls.h 2007-10-07 13:39:08.000000000 +0200 @@ -614,4 +614,10 @@ asmlinkage long sys_fallocate(int fd, in int kernel_execve(const char *filename, char *const argv[], char *const envp[]); +asmlinkage long sys_getshdwinfo(pid_t pid, int func, int __user *data); + +asmlinkage long sys_setshdwinfo(pid_t pid, int func, int data); + +asmlinkage long sys_setshdwpath(pid_t pid, int fd, const char __user *path); + #endif --- orig/arch/i386/kernel/syscall_table.S 2007-10-07 18:59:54.000000000 +0200 +++ new/arch/i386/kernel/syscall_table.S 2007-10-07 20:40:40.000000000 +0200 @@ -222,7 +222,7 @@ ENTRY(sys_call_table) .long sys_getdents64 /* 220 */ .long sys_fcntl64 .long sys_ni_syscall /* reserved for TUX */ - .long sys_ni_syscall + .long sys_getshdwinfo .long sys_gettid .long sys_readahead /* 225 */ .long sys_setxattr @@ -250,7 +250,7 @@ ENTRY(sys_call_table) .long sys_io_submit .long sys_io_cancel .long sys_fadvise64 /* 250 */ - .long sys_ni_syscall + .long sys_setshdwinfo .long sys_exit_group .long sys_lookup_dcookie .long sys_epoll_create @@ -284,7 +284,7 @@ ENTRY(sys_call_table) .long sys_mq_getsetattr .long sys_kexec_load .long sys_waitid - .long sys_ni_syscall /* 285 */ /* available */ + .long sys_setshdwpath /* 285 */ .long sys_add_key .long sys_request_key .long sys_keyctl - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/