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Commit 98de59bf authored by Al Viro's avatar Al Viro
Browse files

take calculation of final prot in security_mmap_file() into a helper



Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9ac4ed4b
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+28 −18
Original line number Original line Diff line number Diff line
@@ -660,36 +660,46 @@ int security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
	return security_ops->file_ioctl(file, cmd, arg);
	return security_ops->file_ioctl(file, cmd, arg);
}
}


int security_mmap_file(struct file *file, unsigned long prot,
static inline unsigned long mmap_prot(struct file *file, unsigned long prot)
			unsigned long flags)
{
{
	unsigned long reqprot = prot;
	int ret;
	/*
	/*
	 * Does the application expect PROT_READ to imply PROT_EXEC?
	 * Does we have PROT_READ and does the application expect
	 *
	 * it to imply PROT_EXEC?  If not, nothing to talk about...
	 * (the exception is when the underlying filesystem is noexec
	 *  mounted, in which case we dont add PROT_EXEC.)
	 */
	 */
	if (!(reqprot & PROT_READ))
	if ((prot & (PROT_READ | PROT_EXEC)) != PROT_READ)
		goto out;
		return prot;
	if (!(current->personality & READ_IMPLIES_EXEC))
	if (!(current->personality & READ_IMPLIES_EXEC))
		goto out;
		return prot;
	if (!file) {
	/*
		prot |= PROT_EXEC;
	 * if that's an anonymous mapping, let it.
	} else if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) {
	 */
	if (!file)
		return prot | PROT_EXEC;
	/*
	 * ditto if it's not on noexec mount, except that on !MMU we need
	 * BDI_CAP_EXEC_MMAP (== VM_MAYEXEC) in this case
	 */
	if (!(file->f_path.mnt->mnt_flags & MNT_NOEXEC)) {
#ifndef CONFIG_MMU
#ifndef CONFIG_MMU
		unsigned long caps = 0;
		unsigned long caps = 0;
		struct address_space *mapping = file->f_mapping;
		struct address_space *mapping = file->f_mapping;
		if (mapping && mapping->backing_dev_info)
		if (mapping && mapping->backing_dev_info)
			caps = mapping->backing_dev_info->capabilities;
			caps = mapping->backing_dev_info->capabilities;
		if (!(caps & BDI_CAP_EXEC_MAP))
		if (!(caps & BDI_CAP_EXEC_MAP))
			goto out;
			return prot;
#endif
#endif
		prot |= PROT_EXEC;
		return prot | PROT_EXEC;
	}
	}
out:
	/* anything on noexec mount won't get PROT_EXEC */
	ret = security_ops->mmap_file(file, reqprot, prot, flags);
	return prot;
}

int security_mmap_file(struct file *file, unsigned long prot,
			unsigned long flags)
{
	int ret;
	ret = security_ops->mmap_file(file, prot,
					mmap_prot(file, prot), flags);
	if (ret)
	if (ret)
		return ret;
		return ret;
	return ima_file_mmap(file, prot);
	return ima_file_mmap(file, prot);