audit: Make testing for a valid loginuid explicit.

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 5f4cdf3ad913fec928835d87fbe499efdf7d67e5..43a97ee1d4c864e4053f86aec5830e037721d125 100644 (file)
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -1275,9 +1275,7 @@ static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir,
        *need_lookup = false;
        dentry = d_lookup(dir, name);
        if (dentry) {
-               if (d_need_lookup(dentry)) {
-                       *need_lookup = true;
-               } else if (dentry->d_flags & DCACHE_OP_REVALIDATE) {
+               if (dentry->d_flags & DCACHE_OP_REVALIDATE) {
                        error = d_revalidate(dentry, flags);
                        if (unlikely(error <= 0)) {
                                if (error < 0) {
@@ -1383,8 +1381,6 @@ static int lookup_fast(struct nameidata *nd, struct qstr *name,
                        return -ECHILD;
                nd->seq = seq;
 
-               if (unlikely(d_need_lookup(dentry)))
-                       goto unlazy;
                if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) {
                        status = d_revalidate(dentry, nd->flags);
                        if (unlikely(status <= 0)) {
@@ -1410,11 +1406,6 @@ unlazy:
        if (unlikely(!dentry))
                goto need_lookup;
 
-       if (unlikely(d_need_lookup(dentry))) {
-               dput(dentry);
-               goto need_lookup;
-       }
-
        if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval)
                status = d_revalidate(dentry, nd->flags);
        if (unlikely(status <= 0)) {
@@ -1859,7 +1850,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
        if (flags & LOOKUP_ROOT) {
                struct inode *inode = nd->root.dentry->d_inode;
                if (*name) {
-                       if (!inode->i_op->lookup)
+                       if (!can_lookup(inode))
                                return -ENOTDIR;
                        retval = inode_permission(inode, MAY_EXEC);
                        if (retval)
@@ -1903,6 +1894,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                        get_fs_pwd(current->fs, &nd->path);
                }
        } else {
+               /* Caller must check execute permissions on the starting path component */
                struct fd f = fdget_raw(dfd);
                struct dentry *dentry;
 
@@ -1912,16 +1904,10 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                dentry = f.file->f_path.dentry;
 
                if (*name) {
-                       if (!S_ISDIR(dentry->d_inode->i_mode)) {
+                       if (!can_lookup(dentry->d_inode)) {
                                fdput(f);
                                return -ENOTDIR;
                        }
-
-                       retval = inode_permission(dentry->d_inode, MAY_EXEC);
-                       if (retval) {
-                               fdput(f);
-                               return retval;
-                       }
                }
 
                nd->path = f.file->f_path;
@@ -2189,15 +2175,19 @@ int user_path_at(int dfd, const char __user *name, unsigned flags,
  *     path-walking is complete.
  */
 static struct filename *
-user_path_parent(int dfd, const char __user *path, struct nameidata *nd)
+user_path_parent(int dfd, const char __user *path, struct nameidata *nd,
+                unsigned int flags)
 {
        struct filename *s = getname(path);
        int error;
 
+       /* only LOOKUP_REVAL is allowed in extra flags */
+       flags &= LOOKUP_REVAL;
+
        if (IS_ERR(s))
                return s;
 
-       error = filename_lookup(dfd, s, LOOKUP_PARENT, nd);
+       error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd);
        if (error) {
                putname(s);
                return ERR_PTR(error);
@@ -3044,12 +3034,22 @@ struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt,
        return file;
 }
 
-struct dentry *kern_path_create(int dfd, const char *pathname, struct path *path, int is_dir)
+struct dentry *kern_path_create(int dfd, const char *pathname,
+                               struct path *path, unsigned int lookup_flags)
 {
        struct dentry *dentry = ERR_PTR(-EEXIST);
        struct nameidata nd;
        int err2;
-       int error = do_path_lookup(dfd, pathname, LOOKUP_PARENT, &nd);
+       int error;
+       bool is_dir = (lookup_flags & LOOKUP_DIRECTORY);
+
+       /*
+        * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any
+        * other flags passed in are ignored!
+        */
+       lookup_flags &= LOOKUP_REVAL;
+
+       error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd);
        if (error)
                return ERR_PTR(error);
 
@@ -3113,13 +3113,14 @@ void done_path_create(struct path *path, struct dentry *dentry)
 }
 EXPORT_SYMBOL(done_path_create);
 
-struct dentry *user_path_create(int dfd, const char __user *pathname, struct path *path, int is_dir)
+struct dentry *user_path_create(int dfd, const char __user *pathname,
+                               struct path *path, unsigned int lookup_flags)
 {
        struct filename *tmp = getname(pathname);
        struct dentry *res;
        if (IS_ERR(tmp))
                return ERR_CAST(tmp);
-       res = kern_path_create(dfd, tmp->name, path, is_dir);
+       res = kern_path_create(dfd, tmp->name, path, lookup_flags);
        putname(tmp);
        return res;
 }
@@ -3175,12 +3176,13 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
        struct dentry *dentry;
        struct path path;
        int error;
+       unsigned int lookup_flags = 0;
 
        error = may_mknod(mode);
        if (error)
                return error;
-
-       dentry = user_path_create(dfd, filename, &path, 0);
+retry:
+       dentry = user_path_create(dfd, filename, &path, lookup_flags);
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);
 
@@ -3203,6 +3205,10 @@ SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode,
        }
 out:
        done_path_create(&path, dentry);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
        return error;
 }
 
@@ -3241,8 +3247,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
        struct dentry *dentry;
        struct path path;
        int error;
+       unsigned int lookup_flags = LOOKUP_DIRECTORY;
 
-       dentry = user_path_create(dfd, pathname, &path, 1);
+retry:
+       dentry = user_path_create(dfd, pathname, &path, lookup_flags);
        if (IS_ERR(dentry))
                return PTR_ERR(dentry);
 
@@ -3252,6 +3260,10 @@ SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode)
        if (!error)
                error = vfs_mkdir(path.dentry->d_inode, dentry, mode);
        done_path_create(&path, dentry);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
        return error;
 }
 
@@ -3327,8 +3339,9 @@ static long do_rmdir(int dfd, const char __user *pathname)
        struct filename *name;
        struct dentry *dentry;
        struct nameidata nd;
-
-       name = user_path_parent(dfd, pathname, &nd);
+       unsigned int lookup_flags = 0;
+retry:
+       name = user_path_parent(dfd, pathname, &nd, lookup_flags);
        if (IS_ERR(name))
                return PTR_ERR(name);
 
@@ -3370,6 +3383,10 @@ exit2:
 exit1:
        path_put(&nd.path);
        putname(name);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
        return error;
 }
 
@@ -3423,8 +3440,9 @@ static long do_unlinkat(int dfd, const char __user *pathname)
        struct dentry *dentry;
        struct nameidata nd;
        struct inode *inode = NULL;
-
-       name = user_path_parent(dfd, pathname, &nd);
+       unsigned int lookup_flags = 0;
+retry:
+       name = user_path_parent(dfd, pathname, &nd, lookup_flags);
        if (IS_ERR(name))
                return PTR_ERR(name);
 
@@ -3462,6 +3480,11 @@ exit2:
 exit1:
        path_put(&nd.path);
        putname(name);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               inode = NULL;
+               goto retry;
+       }
        return error;
 
 slashes:
@@ -3513,12 +3536,13 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
        struct filename *from;
        struct dentry *dentry;
        struct path path;
+       unsigned int lookup_flags = 0;
 
        from = getname(oldname);
        if (IS_ERR(from))
                return PTR_ERR(from);
-
-       dentry = user_path_create(newdfd, newname, &path, 0);
+retry:
+       dentry = user_path_create(newdfd, newname, &path, lookup_flags);
        error = PTR_ERR(dentry);
        if (IS_ERR(dentry))
                goto out_putname;
@@ -3527,6 +3551,10 @@ SYSCALL_DEFINE3(symlinkat, const char __user *, oldname,
        if (!error)
                error = vfs_symlink(path.dentry->d_inode, dentry, from->name);
        done_path_create(&path, dentry);
+       if (retry_estale(error, lookup_flags)) {
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
 out_putname:
        putname(from);
        return error;
@@ -3613,12 +3641,13 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
 
        if (flags & AT_SYMLINK_FOLLOW)
                how |= LOOKUP_FOLLOW;
-
+retry:
        error = user_path_at(olddfd, oldname, how, &old_path);
        if (error)
                return error;
 
-       new_dentry = user_path_create(newdfd, newname, &new_path, 0);
+       new_dentry = user_path_create(newdfd, newname, &new_path,
+                                       (how & LOOKUP_REVAL));
        error = PTR_ERR(new_dentry);
        if (IS_ERR(new_dentry))
                goto out;
@@ -3635,6 +3664,10 @@ SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname,
        error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry);
 out_dput:
        done_path_create(&new_path, new_dentry);
+       if (retry_estale(error, how)) {
+               how |= LOOKUP_REVAL;
+               goto retry;
+       }
 out:
        path_put(&old_path);
 
@@ -3807,15 +3840,17 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
        struct nameidata oldnd, newnd;
        struct filename *from;
        struct filename *to;
+       unsigned int lookup_flags = 0;
+       bool should_retry = false;
        int error;
-
-       from = user_path_parent(olddfd, oldname, &oldnd);
+retry:
+       from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
        if (IS_ERR(from)) {
                error = PTR_ERR(from);
                goto exit;
        }
 
-       to = user_path_parent(newdfd, newname, &newnd);
+       to = user_path_parent(newdfd, newname, &newnd, lookup_flags);
        if (IS_ERR(to)) {
                error = PTR_ERR(to);
                goto exit1;
@@ -3887,11 +3922,18 @@ exit3:
        unlock_rename(new_dir, old_dir);
        mnt_drop_write(oldnd.path.mnt);
 exit2:
+       if (retry_estale(error, lookup_flags))
+               should_retry = true;
        path_put(&newnd.path);
        putname(to);
 exit1:
        path_put(&oldnd.path);
        putname(from);
+       if (should_retry) {
+               should_retry = false;
+               lookup_flags |= LOOKUP_REVAL;
+               goto retry;
+       }
 exit:
        return error;
 }