Add a simple helper perform a link with a kernel space file name and use it in the early init code instead of relying on the implicit set_fs(KERNEL_DS) there. To do so push the getname from do_linkat into the callers. Remove the now unused ksys_link.
Signed-off-by: Christoph Hellwig <[email protected]> --- fs/internal.h | 2 -- fs/namei.c | 39 +++++++++++++++++++++++++++++---------- include/linux/fs.h | 1 + include/linux/syscalls.h | 9 --------- init/initramfs.c | 2 +- 5 files changed, 31 insertions(+), 22 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 1e7a72bd183e63..f0869d5dc4dbfa 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -66,8 +66,6 @@ long do_rmdir(int dfd, const char __user *pathname); long do_unlinkat(int dfd, struct filename *name); long do_symlinkat(const char __user *oldname, int newdfd, const char __user *newname); -int do_linkat(int olddfd, const char __user *oldname, int newdfd, - const char __user *newname, int flags); /* * namespace.c diff --git a/fs/namei.c b/fs/namei.c index de97edac21849d..9d80a5bce1051a 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4122,8 +4122,8 @@ EXPORT_SYMBOL(vfs_link); * with linux 2.0, and to avoid hard-linking to directories * and other special files. --ADM */ -int do_linkat(int olddfd, const char __user *oldname, int newdfd, - const char __user *newname, int flags) +static int do_linkat(int olddfd, struct filename *oldname, int newdfd, + struct filename *newname, int flags) { struct dentry *new_dentry; struct path old_path, new_path; @@ -4131,27 +4131,29 @@ int do_linkat(int olddfd, const char __user *oldname, int newdfd, int how = 0; int error; + error = -EINVAL; if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) - return -EINVAL; + goto out_put_both_names; /* * To use null names we require CAP_DAC_READ_SEARCH * This ensures that not everyone will be able to create * handlink using the passed filedescriptor. */ if (flags & AT_EMPTY_PATH) { + error = -ENOENT; if (!capable(CAP_DAC_READ_SEARCH)) - return -ENOENT; + goto out_put_both_names; how = LOOKUP_EMPTY; } if (flags & AT_SYMLINK_FOLLOW) how |= LOOKUP_FOLLOW; retry: - error = user_path_at(olddfd, oldname, how, &old_path); + error = filename_lookup(olddfd, oldname, how, &old_path, NULL); if (error) - return error; + goto out_put_newname; - new_dentry = user_path_create(newdfd, newname, &new_path, + new_dentry = filename_create(newdfd, newname, &new_path, (how & LOOKUP_REVAL)); error = PTR_ERR(new_dentry); if (IS_ERR(new_dentry)) @@ -4181,21 +4183,38 @@ int do_linkat(int olddfd, const char __user *oldname, int newdfd, how |= LOOKUP_REVAL; goto retry; } + putname(newname); out: path_put(&old_path); - + putname(oldname); + return error; +out_put_both_names: + if (!IS_ERR(oldname)) + putname(oldname); +out_put_newname: + if (!IS_ERR(newname)) + putname(newname); return error; } +int __init kern_link(const char *oldname, const char *newname) +{ + return do_linkat(AT_FDCWD, getname_kernel(oldname), AT_FDCWD, + getname_kernel(newname), 0); +} + SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, int, newdfd, const char __user *, newname, int, flags) { - return do_linkat(olddfd, oldname, newdfd, newname, flags); + int how = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0; + + return do_linkat(olddfd, getname_flags(oldname, how, NULL), newdfd, + getname(newname), flags); } SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) { - return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); + return do_linkat(AT_FDCWD, getname(oldname), AT_FDCWD, getname(newname), 0); } /** diff --git a/include/linux/fs.h b/include/linux/fs.h index 846a21a9b3e14c..fc3b09d473945f 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3679,5 +3679,6 @@ int __init kern_chmod(const char *filename, umode_t mode); int __init kern_utimes(const char *filename, struct timespec64 *tv, int flags); int kern_mkdir(const char *pathname, umode_t mode); int kern_mknod(const char *filename, umode_t mode, unsigned int dev); +int __init kern_link(const char *oldname, const char *newname); #endif /* _LINUX_FS_H */ diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 3dfcae351a077d..467cc4413874ed 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1293,15 +1293,6 @@ static inline long ksys_symlink(const char __user *oldname, return do_symlinkat(oldname, AT_FDCWD, newname); } -extern int do_linkat(int olddfd, const char __user *oldname, int newdfd, - const char __user *newname, int flags); - -static inline long ksys_link(const char __user *oldname, - const char __user *newname) -{ - return do_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); -} - extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); static inline long ksys_ftruncate(unsigned int fd, loff_t length) diff --git a/init/initramfs.c b/init/initramfs.c index f32226d0388100..e484381c6c131b 100644 --- a/init/initramfs.c +++ b/init/initramfs.c @@ -310,7 +310,7 @@ static int __init maybe_link(void) char *old = find_link(major, minor, ino, mode, collected); if (old) { clean_path(collected, 0); - return (ksys_link(old, collected) < 0) ? -1 : 1; + return (kern_link(old, collected) < 0) ? -1 : 1; } } return 0; -- 2.27.0
