Commit 8bb79224 authored by Al Viro's avatar Al Viro
Browse files

[PATCH] permission checks for chdir need special treatment only on the last step 



... so we ought to pass MAY_CHDIR to vfs_permission() instead of having
it triggered on every step of preceding pathname resolution.  LOOKUP_CHDIR
is killed by that.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent db2e747b

fs/namei.c

+0 −2
Original line number Diff line number Diff line
@@ -268,8 +268,6 @@ int permission(struct inode *inode, int mask, struct nameidata *nd) 
		if (nd) {

			if (nd->flags & LOOKUP_ACCESS)

				extra |= MAY_ACCESS;

			if (nd->flags & LOOKUP_CHDIR)

				extra |= MAY_CHDIR;

			if (nd->flags & LOOKUP_OPEN)

				extra |= MAY_OPEN;

		}

fs/open.c

+2 −3
Original line number Diff line number Diff line
@@ -501,12 +501,11 @@ asmlinkage long sys_chdir(const char __user * filename) 
	struct nameidata nd;

	int error;



	error = __user_walk(filename,

			    LOOKUP_FOLLOW|LOOKUP_DIRECTORY|LOOKUP_CHDIR, &nd);

	error = __user_walk(filename, LOOKUP_FOLLOW|LOOKUP_DIRECTORY, &nd);

	if (error)

		goto out;



	error = vfs_permission(&nd, MAY_EXEC);

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

	if (error)

		goto dput_and_out;

include/linux/namei.h

+0 −1
Original line number Diff line number Diff line
@@ -55,7 +55,6 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; 
#define LOOKUP_OPEN		(0x0100)

#define LOOKUP_CREATE		(0x0200)

#define LOOKUP_ACCESS		(0x0400)

#define LOOKUP_CHDIR		(0x0800)



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

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

CRA Git | Maintained and supported by SUSTech CRA and CCSE