Unverified Commit e67fe633 authored by Christian Brauner's avatar Christian Brauner Committed by Christian Brauner (Microsoft)
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fs: port i_{g,u}id_into_vfs{g,u}id() to mnt_idmap 



Convert to struct mnt_idmap.
Remove legacy file_mnt_user_ns() and mnt_user_ns().

Last cycle we merged the necessary infrastructure in
256c8aed ("fs: introduce dedicated idmap type for mounts").
This is just the conversion to struct mnt_idmap.

Currently we still pass around the plain namespace that was attached to a
mount. This is in general pretty convenient but it makes it easy to
conflate namespaces that are relevant on the filesystem with namespaces
that are relevent on the mount level. Especially for non-vfs developers
without detailed knowledge in this area this can be a potential source for
bugs.

Once the conversion to struct mnt_idmap is done all helpers down to the
really low-level helpers will take a struct mnt_idmap argument instead of
two namespace arguments. This way it becomes impossible to conflate the two
eliminating the possibility of any bugs. All of the vfs and all filesystems
only operate on struct mnt_idmap.

Acked-by: default avatarDave Chinner <dchinner@redhat.com>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChristian Brauner (Microsoft) <brauner@kernel.org>
parent 0dbe12f2

fs/attr.c

+8 −16
Original line number Diff line number Diff line
@@ -36,15 +36,13 @@ 
int setattr_should_drop_sgid(struct mnt_idmap *idmap,

			     const struct inode *inode)

{

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);

	umode_t mode = inode->i_mode;



	if (!(mode & S_ISGID))

		return 0;

	if (mode & S_IXGRP)

		return ATTR_KILL_SGID;

	if (!in_group_or_capable(idmap, inode,

				 i_gid_into_vfsgid(mnt_userns, inode)))

	if (!in_group_or_capable(idmap, inode, i_gid_into_vfsgid(idmap, inode)))

		return ATTR_KILL_SGID;

	return 0;

}
@@ -98,9 +96,7 @@ EXPORT_SYMBOL(setattr_should_drop_suidgid); 
static bool chown_ok(struct mnt_idmap *idmap,

		     const struct inode *inode, vfsuid_t ia_vfsuid)

{

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);



	vfsuid_t vfsuid = i_uid_into_vfsuid(mnt_userns, inode);

	vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);

	if (vfsuid_eq_kuid(vfsuid, current_fsuid()) &&

	    vfsuid_eq(ia_vfsuid, vfsuid))

		return true;
@@ -127,10 +123,8 @@ static bool chown_ok(struct mnt_idmap *idmap, 
static bool chgrp_ok(struct mnt_idmap *idmap,

		     const struct inode *inode, vfsgid_t ia_vfsgid)

{

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);



	vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode);

	vfsuid_t vfsuid = i_uid_into_vfsuid(mnt_userns, inode);

	vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);

	vfsuid_t vfsuid = i_uid_into_vfsuid(idmap, inode);

	if (vfsuid_eq_kuid(vfsuid, current_fsuid())) {

		if (vfsgid_eq(ia_vfsgid, vfsgid))

			return true;
@@ -169,7 +163,6 @@ static bool chgrp_ok(struct mnt_idmap *idmap, 
int setattr_prepare(struct mnt_idmap *idmap, struct dentry *dentry,

		    struct iattr *attr)

{

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);

	struct inode *inode = d_inode(dentry);

	unsigned int ia_valid = attr->ia_valid;
@@ -207,7 +200,7 @@ int setattr_prepare(struct mnt_idmap *idmap, struct dentry *dentry, 
		if (ia_valid & ATTR_GID)

			vfsgid = attr->ia_vfsgid;

		else

			vfsgid = i_gid_into_vfsgid(mnt_userns, inode);

			vfsgid = i_gid_into_vfsgid(idmap, inode);



		/* Also check the setgid bit! */

		if (!in_group_or_capable(idmap, inode, vfsgid))
@@ -308,7 +301,6 @@ EXPORT_SYMBOL(inode_newsize_ok); 
void setattr_copy(struct mnt_idmap *idmap, struct inode *inode,

		  const struct iattr *attr)

{

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);

	unsigned int ia_valid = attr->ia_valid;



	i_uid_update(idmap, attr, inode);
@@ -322,7 +314,7 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, 
	if (ia_valid & ATTR_MODE) {

		umode_t mode = attr->ia_mode;

		if (!in_group_or_capable(idmap, inode,

					 i_gid_into_vfsgid(mnt_userns, inode)))

					 i_gid_into_vfsgid(idmap, inode)))

			mode &= ~S_ISGID;

		inode->i_mode = mode;

	}
@@ -473,10 +465,10 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, 
	 * gids unless those uids & gids are being made valid.

	 */

	if (!(ia_valid & ATTR_UID) &&

	    !vfsuid_valid(i_uid_into_vfsuid(mnt_userns, inode)))

	    !vfsuid_valid(i_uid_into_vfsuid(idmap, inode)))

		return -EOVERFLOW;

	if (!(ia_valid & ATTR_GID) &&

	    !vfsgid_valid(i_gid_into_vfsgid(mnt_userns, inode)))

	    !vfsgid_valid(i_gid_into_vfsgid(idmap, inode)))

		return -EOVERFLOW;



	error = security_inode_setattr(idmap, dentry, attr);

fs/coredump.c

+1 −3
Original line number Diff line number Diff line
@@ -645,7 +645,6 @@ void do_coredump(const kernel_siginfo_t *siginfo) 
		}

	} else {

		struct mnt_idmap *idmap;

		struct user_namespace *mnt_userns;

		struct inode *inode;

		int open_flags = O_CREAT | O_RDWR | O_NOFOLLOW |

				 O_LARGEFILE | O_EXCL;
@@ -724,8 +723,7 @@ void do_coredump(const kernel_siginfo_t *siginfo) 
		 * filesystem.

		 */

		idmap = file_mnt_idmap(cprm.file);

		mnt_userns = mnt_idmap_owner(idmap);

		if (!vfsuid_eq_kuid(i_uid_into_vfsuid(mnt_userns, inode),

		if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode),

				    current_fsuid())) {

			pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n",

					    cn.corename);

fs/exec.c

+4 −4
Original line number Diff line number Diff line
@@ -1596,7 +1596,7 @@ static void check_unsafe_exec(struct linux_binprm *bprm) 
static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file)

{

	/* Handle suid and sgid on files */

	struct user_namespace *mnt_userns;

	struct mnt_idmap *idmap;

	struct inode *inode = file_inode(file);

	unsigned int mode;

	vfsuid_t vfsuid;
@@ -1612,15 +1612,15 @@ static void bprm_fill_uid(struct linux_binprm *bprm, struct file *file) 
	if (!(mode & (S_ISUID|S_ISGID)))

		return;



	mnt_userns = file_mnt_user_ns(file);

	idmap = file_mnt_idmap(file);



	/* Be careful if suid/sgid is set */

	inode_lock(inode);



	/* reload atomically mode/uid/gid now that lock held */

	mode = inode->i_mode;

	vfsuid = i_uid_into_vfsuid(mnt_userns, inode);

	vfsgid = i_gid_into_vfsgid(mnt_userns, inode);

	vfsuid = i_uid_into_vfsuid(idmap, inode);

	vfsgid = i_gid_into_vfsgid(idmap, inode);

	inode_unlock(inode);



	/* We ignore suid/sgid if there are no mappings for them in the ns */

fs/f2fs/acl.c

+1 −2
Original line number Diff line number Diff line
@@ -209,7 +209,6 @@ static int f2fs_acl_update_mode(struct mnt_idmap *idmap, 
				struct posix_acl **acl)

{

	umode_t mode = inode->i_mode;

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);

	int error;



	if (is_inode_flag_set(inode, FI_ACL_MODE))
@@ -220,7 +219,7 @@ static int f2fs_acl_update_mode(struct mnt_idmap *idmap, 
		return error;

	if (error == 0)

		*acl = NULL;

	if (!vfsgid_in_group_p(i_gid_into_vfsgid(mnt_userns, inode)) &&

	if (!vfsgid_in_group_p(i_gid_into_vfsgid(idmap, inode)) &&

	    !capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))

		mode &= ~S_ISGID;

	*mode_p = mode;

fs/f2fs/file.c

+1 −2
Original line number Diff line number Diff line
@@ -907,7 +907,6 @@ static void __setattr_copy(struct mnt_idmap *idmap, 
			   struct inode *inode, const struct iattr *attr)

{

	unsigned int ia_valid = attr->ia_valid;

	struct user_namespace *mnt_userns = mnt_idmap_owner(idmap);



	i_uid_update(idmap, attr, inode);

	i_gid_update(idmap, attr, inode);
@@ -919,7 +918,7 @@ static void __setattr_copy(struct mnt_idmap *idmap, 
		inode->i_ctime = attr->ia_ctime;

	if (ia_valid & ATTR_MODE) {

		umode_t mode = attr->ia_mode;

		vfsgid_t vfsgid = i_gid_into_vfsgid(mnt_userns, inode);

		vfsgid_t vfsgid = i_gid_into_vfsgid(idmap, inode);



		if (!vfsgid_in_group_p(vfsgid) &&

		    !capable_wrt_inode_uidgid(idmap, inode, CAP_FSETID))