Skip to main content

Browse the archive

Revision 4d59b6ccf000862beed6fc0765d3209f98a8d8a2 authored by Tejun Heo on 08 February 2017, 22:30:56 UTC, committed by Linus Torvalds on 08 February 2017, 23:41:43 UTC 
cpumask: use nr_cpumask_bits for parsing functions
 
Commit 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and
parsing functions") converted both cpumask printing and parsing
functions to use nr_cpu_ids instead of nr_cpumask_bits.  While this was
okay for the printing functions as it just picked one of the two output
formats that we were alternating between depending on a kernel config,
doing the same for parsing wasn't okay.

nr_cpumask_bits can be either nr_cpu_ids or NR_CPUS.  We can always use
nr_cpu_ids but that is a variable while NR_CPUS is a constant, so it can
be more efficient to use NR_CPUS when we can get away with it.
Converting the printing functions to nr_cpu_ids makes sense because it
affects how the masks get presented to userspace and doesn't break
anything; however, using nr_cpu_ids for parsing functions can
incorrectly leave the higher bits uninitialized while reading in these
masks from userland.  As all testing and comparison functions use
nr_cpumask_bits which can be larger than nr_cpu_ids, the parsed cpumasks
can erroneously yield false negative results.

This made the taskstats interface incorrectly return -EINVAL even when
the inputs were correct.

Fix it by restoring the parse functions to use nr_cpumask_bits instead
of nr_cpu_ids.

Link: http://lkml.kernel.org/r/20170206182442.GB31078@htj.duckdns.org
Fixes: 513e3d2d11c9 ("cpumask: always use nr_cpu_ids in formatting and parsing functions")
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Martin Steigerwald <martin.steigerwald@teamix.de>
Debugged-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: <stable@vger.kernel.org>	[4.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0911d00
Raw File
ima.h 
/*
 * Copyright (C) 2008 IBM Corporation
 * Author: Mimi Zohar <zohar@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2 of the License.
 */

#ifndef _LINUX_IMA_H
#define _LINUX_IMA_H

#include <linux/fs.h>
#include <linux/kexec.h>
struct linux_binprm;

#ifdef CONFIG_IMA
extern int ima_bprm_check(struct linux_binprm *bprm);
extern int ima_file_check(struct file *file, int mask, int opened);
extern void ima_file_free(struct file *file);
extern int ima_file_mmap(struct file *file, unsigned long prot);
extern int ima_read_file(struct file *file, enum kernel_read_file_id id);
extern int ima_post_read_file(struct file *file, void *buf, loff_t size,
			      enum kernel_read_file_id id);
extern void ima_post_path_mknod(struct dentry *dentry);

#ifdef CONFIG_IMA_KEXEC
extern void ima_add_kexec_buffer(struct kimage *image);
#endif

#else
static inline int ima_bprm_check(struct linux_binprm *bprm)
{
	return 0;
}

static inline int ima_file_check(struct file *file, int mask, int opened)
{
	return 0;
}

static inline void ima_file_free(struct file *file)
{
	return;
}

static inline int ima_file_mmap(struct file *file, unsigned long prot)
{
	return 0;
}

static inline int ima_read_file(struct file *file, enum kernel_read_file_id id)
{
	return 0;
}

static inline int ima_post_read_file(struct file *file, void *buf, loff_t size,
				     enum kernel_read_file_id id)
{
	return 0;
}

static inline void ima_post_path_mknod(struct dentry *dentry)
{
	return;
}

#endif /* CONFIG_IMA */

#ifndef CONFIG_IMA_KEXEC
struct kimage;

static inline void ima_add_kexec_buffer(struct kimage *image)
{}
#endif

#ifdef CONFIG_IMA_APPRAISE
extern void ima_inode_post_setattr(struct dentry *dentry);
extern int ima_inode_setxattr(struct dentry *dentry, const char *xattr_name,
		       const void *xattr_value, size_t xattr_value_len);
extern int ima_inode_removexattr(struct dentry *dentry, const char *xattr_name);
#else
static inline void ima_inode_post_setattr(struct dentry *dentry)
{
	return;
}

static inline int ima_inode_setxattr(struct dentry *dentry,
				     const char *xattr_name,
				     const void *xattr_value,
				     size_t xattr_value_len)
{
	return 0;
}

static inline int ima_inode_removexattr(struct dentry *dentry,
					const char *xattr_name)
{
	return 0;
}
#endif /* CONFIG_IMA_APPRAISE */
#endif /* _LINUX_IMA_H */
back to top