From: Miklos Szeredi In the "operation does permission checking" model used by fuse, chdir permission is not checked, since there's no chdir method. For this case set a lookup flag, which will be passed to ->permission(), so fuse can distinguish it from permission checks for other operations. Signed-off-by: Miklos Szeredi Cc: Al Viro Signed-off-by: Andrew Morton --- fs/fuse/dir.c | 2 +- fs/open.c | 3 ++- include/linux/namei.h | 1 + 3 files changed, 4 insertions(+), 2 deletions(-) diff -puN fs/fuse/dir.c~vfs-define-new-lookup-flag-for-chdir fs/fuse/dir.c --- a/fs/fuse/dir.c~vfs-define-new-lookup-flag-for-chdir +++ a/fs/fuse/dir.c @@ -776,7 +776,7 @@ static int fuse_permission(struct inode if ((mask & MAY_EXEC) && !S_ISDIR(mode) && !(mode & S_IXUGO)) return -EACCES; - if (nd && (nd->flags & LOOKUP_ACCESS)) + if (nd && (nd->flags & (LOOKUP_ACCESS | LOOKUP_CHDIR))) return fuse_access(inode, mask); return 0; } diff -puN fs/open.c~vfs-define-new-lookup-flag-for-chdir fs/open.c --- a/fs/open.c~vfs-define-new-lookup-flag-for-chdir +++ a/fs/open.c @@ -546,7 +546,8 @@ asmlinkage long sys_chdir(const char __u struct nameidata nd; int error; - error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd); + error = __user_walk(filename, + LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd); if (error) goto out; diff -puN include/linux/namei.h~vfs-define-new-lookup-flag-for-chdir include/linux/namei.h --- a/include/linux/namei.h~vfs-define-new-lookup-flag-for-chdir +++ a/include/linux/namei.h @@ -54,6 +54,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LA #define LOOKUP_OPEN (0x0100) #define LOOKUP_CREATE (0x0200) #define LOOKUP_ACCESS (0x0400) +#define LOOKUP_CHDIR (0x0800) extern int FASTCALL(__user_walk(const char __user *, unsigned, struct nameidata *)); extern int FASTCALL(__user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *)); _