Commit a110343f authored by Al Viro's avatar Al Viro
Browse files

[PATCH] fix MAY_CHDIR/MAY_ACCESS/LOOKUP_ACCESS mess 



* MAY_CHDIR is redundant - it's an equivalent of MAY_ACCESS
* MAY_ACCESS on fuse should affect only the last step of pathname resolution
* fchdir() and chroot() should pass MAY_ACCESS, for the same reason why
  chdir() needs that.
* now that we pass MAY_ACCESS explicitly in all cases, LOOKUP_ACCESS can be
  removed; it has no business being in nameidata.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 7f2da1e7

fs/fuse/dir.c

+1 −1
Original line number Diff line number Diff line
@@ -962,7 +962,7 @@ 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 | MAY_CHDIR)) {

	} else if (mask & MAY_ACCESS) {

		err = fuse_access(inode, mask);

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

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

fs/namei.c

+0 −2
Original line number Diff line number Diff line
@@ -265,8 +265,6 @@ int permission(struct inode *inode, int mask, struct nameidata *nd) 
	if (inode->i_op && inode->i_op->permission) {

		int extra = 0;

		if (nd) {

			if (nd->flags & LOOKUP_ACCESS)

				extra |= MAY_ACCESS;

			if (nd->flags & LOOKUP_OPEN)

				extra |= MAY_OPEN;

		}

fs/open.c

+5 −5
Original line number Diff line number Diff line
@@ -457,11 +457,11 @@ asmlinkage long sys_faccessat(int dfd, const char __user *filename, int mode) 
			old_cap = cap_set_effective(current->cap_permitted);

	}



	res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW|LOOKUP_ACCESS, &nd);

	res = __user_walk_fd(dfd, filename, LOOKUP_FOLLOW, &nd);

	if (res)

		goto out;



	res = vfs_permission(&nd, mode);

	res = vfs_permission(&nd, mode | MAY_ACCESS);

	/* SuS v2 requires we report a read only fs too */

	if(res || !(mode & S_IWOTH) ||

	   special_file(nd.path.dentry->d_inode->i_mode))
@@ -505,7 +505,7 @@ asmlinkage long sys_chdir(const char __user * filename) 
	if (error)

		goto out;



	error = vfs_permission(&nd, MAY_EXEC | MAY_CHDIR);

	error = vfs_permission(&nd, MAY_EXEC | MAY_ACCESS);

	if (error)

		goto dput_and_out;
@@ -534,7 +534,7 @@ asmlinkage long sys_fchdir(unsigned int fd) 
	if (!S_ISDIR(inode->i_mode))

		goto out_putf;



	error = file_permission(file, MAY_EXEC);

	error = file_permission(file, MAY_EXEC | MAY_ACCESS);

	if (!error)

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

out_putf:
@@ -552,7 +552,7 @@ asmlinkage long sys_chroot(const char __user * filename) 
	if (error)

		goto out;



	error = vfs_permission(&nd, MAY_EXEC);

	error = vfs_permission(&nd, MAY_EXEC | MAY_ACCESS);

	if (error)

		goto dput_and_out;

include/linux/fs.h

+1 −2
Original line number Diff line number Diff line
@@ -61,8 +61,7 @@ extern int dir_notify_enable; 
#define MAY_READ 4

#define MAY_APPEND 8

#define MAY_ACCESS 16

#define MAY_CHDIR 32

#define MAY_OPEN 64

#define MAY_OPEN 32



#define FMODE_READ 1

#define FMODE_WRITE 2

include/linux/namei.h

+0 −1
Original line number Diff line number Diff line
@@ -53,7 +53,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; 
 */

#define LOOKUP_OPEN		(0x0100)

#define LOOKUP_CREATE		(0x0200)

#define LOOKUP_ACCESS		(0x0400)



extern int __user_walk(const char __user *, unsigned, struct nameidata *);

extern int __user_walk_fd(int dfd, const char __user *, unsigned, struct nameidata *);

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