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Commit 8b6a5a37 authored by Eric Paris's avatar Eric Paris Committed by James Morris
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SELinux: check open perms in dentry_open not inode_permission 



Some operations, like searching a directory path or connecting a unix domain
socket, make explicit calls into inode_permission.  Our choices are to
either try to come up with a signature for all of the explicit calls to
inode_permission and do not check open on those, or to move the open checks to
dentry_open where we know this is always an open operation.  This patch moves
the checks to dentry_open.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent 0da939b0

security/selinux/hooks.c

+30 −29
Original line number Diff line number Diff line
@@ -1686,15 +1686,39 @@ static inline u32 file_mask_to_av(int mode, int mask) 
	return av;

}



/* Convert a Linux file to an access vector. */

static inline u32 file_to_av(struct file *file)

{

	u32 av = 0;



	if (file->f_mode & FMODE_READ)

		av |= FILE__READ;

	if (file->f_mode & FMODE_WRITE) {

		if (file->f_flags & O_APPEND)

			av |= FILE__APPEND;

		else

			av |= FILE__WRITE;

	}

	if (!av) {

		/*

		 * Special file opened with flags 3 for ioctl-only use.

		 */

		av = FILE__IOCTL;

	}



	return av;

}



/*

 * Convert a file mask to an access vector and include the correct open

 * Convert a file to an access vector and include the correct open

 * open permission.

 */

static inline u32 open_file_mask_to_av(int mode, int mask)

static inline u32 open_file_to_av(struct file *file)

{

	u32 av = file_mask_to_av(mode, mask);

	u32 av = file_to_av(file);



	if (selinux_policycap_openperm) {

		mode_t mode = file->f_path.dentry->d_inode->i_mode;

		/*

		 * lnk files and socks do not really have an 'open'

		 */
@@ -1710,34 +1734,11 @@ static inline u32 open_file_mask_to_av(int mode, int mask) 
			av |= DIR__OPEN;

		else

			printk(KERN_ERR "SELinux: WARNING: inside %s with "

				"unknown mode:%x\n", __func__, mode);

				"unknown mode:%o\n", __func__, mode);

	}

	return av;

}



/* Convert a Linux file to an access vector. */

static inline u32 file_to_av(struct file *file)

{

	u32 av = 0;



	if (file->f_mode & FMODE_READ)

		av |= FILE__READ;

	if (file->f_mode & FMODE_WRITE) {

		if (file->f_flags & O_APPEND)

			av |= FILE__APPEND;

		else

			av |= FILE__WRITE;

	}

	if (!av) {

		/*

		 * Special file opened with flags 3 for ioctl-only use.

		 */

		av = FILE__IOCTL;

	}



	return av;

}



/* Hook functions begin here. */



static int selinux_ptrace_may_access(struct task_struct *child,
@@ -2654,7 +2655,7 @@ static int selinux_inode_permission(struct inode *inode, int mask) 
	}



	return inode_has_perm(current, inode,

			       open_file_mask_to_av(inode->i_mode, mask), NULL);

			      file_mask_to_av(inode->i_mode, mask), NULL);

}



static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr)
@@ -3170,7 +3171,7 @@ static int selinux_dentry_open(struct file *file) 
	 * new inode label or new policy.

	 * This check is not redundant - do not remove.

	 */

	return inode_has_perm(current, inode, file_to_av(file), NULL);

	return inode_has_perm(current, inode, open_file_to_av(file), NULL);

}



/* task security operations */