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Commit 9cfcac81 authored by Eric Paris's avatar Eric Paris Committed by James Morris
Browse files

vfs: re-introduce MAY_CHDIR 



Currently MAY_ACCESS means that filesystems must check the permissions
right then and not rely on cached results or the results of future
operations on the object.  This can be because of a call to sys_access() or
because of a call to chdir() which needs to check search without relying on
any future operations inside that dir.  I plan to use MAY_ACCESS for other
purposes in the security system, so I split the MAY_ACCESS and the
MAY_CHDIR cases.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Acked-by: default avatarStephen D. Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 692a8a23

fs/fuse/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -1016,7 +1016,7 @@ static int fuse_permission(struct inode *inode, int mask) 
		   exist.  So if permissions are revoked this won't be

		   noticed immediately, only after the attribute

		   timeout has expired */

	} else if (mask & MAY_ACCESS) {

	} else if (mask & (MAY_ACCESS | MAY_CHDIR)) {

		err = fuse_access(inode, mask);

	} else if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode)) {

		if (!(inode->i_mode & S_IXUGO)) {

fs/nfs/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -1953,7 +1953,7 @@ int nfs_permission(struct inode *inode, int mask) 
	if ((mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0)

		goto out;

	/* Is this sys_access() ? */

	if (mask & MAY_ACCESS)

	if (mask & (MAY_ACCESS | MAY_CHDIR))

		goto force_lookup;



	switch (inode->i_mode & S_IFMT) {

fs/open.c

+3 −3
Original line number Diff line number Diff line
@@ -366,7 +366,7 @@ SYSCALL_DEFINE1(chdir, const char __user *, filename) 
	if (error)

		goto out;



	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);

	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);

	if (error)

		goto dput_and_out;
@@ -395,7 +395,7 @@ SYSCALL_DEFINE1(fchdir, unsigned int, fd) 
	if (!S_ISDIR(inode->i_mode))

		goto out_putf;



	error = inode_permission(inode, MAY_EXEC | MAY_ACCESS);

	error = inode_permission(inode, MAY_EXEC | MAY_CHDIR);

	if (!error)

		set_fs_pwd(current->fs, &file->f_path);

out_putf:
@@ -413,7 +413,7 @@ SYSCALL_DEFINE1(chroot, const char __user *, filename) 
	if (error)

		goto out;



	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_ACCESS);

	error = inode_permission(path.dentry->d_inode, MAY_EXEC | MAY_CHDIR);

	if (error)

		goto dput_and_out;

include/linux/fs.h

+1 −0
Original line number Diff line number Diff line
@@ -53,6 +53,7 @@ struct inodes_stat_t { 
#define MAY_APPEND 8

#define MAY_ACCESS 16

#define MAY_OPEN 32

#define MAY_CHDIR 64



/*

 * flags in file.f_mode.  Note that FMODE_READ and FMODE_WRITE must correspond