Commit 6b918c6f authored by Feng Tang's avatar Feng Tang Committed by Ma Wupeng
Browse files

mm/mempolicy: unify the parameter sanity check for mbind and set_mempolicy 

mainline inclusion
from mainline-v5.14-rc1
commit 95837924
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I6I1Z2
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=95837924587c60425f941dc8cbfba61cb964fcb5

--------------------------------

Currently the kernel_mbind() and kernel_set_mempolicy() do almost the same
operation for parameter sanity check.

Add a helper function to unify the code to reduce the redundancy, and make
it easier for changing the sanity check code in future.

[thanks to David Rientjes for suggesting using helper function instead of
macro].

[feng.tang@intel.com: add comment]
  Link: https://lkml.kernel.org/r/1622560492-1294-4-git-send-email-feng.tang@intel.com

Link: https://lkml.kernel.org/r/1622469956-82897-4-git-send-email-feng.tang@intel.com


Signed-off-by: default avatarFeng Tang <feng.tang@intel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Ben Widawsky <ben.widawsky@intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarMa Wupeng <mawupeng1@huawei.com>
parent d634f94d

mm/mempolicy.c

+30 −18
Original line number Diff line number Diff line
@@ -1474,26 +1474,38 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, 
	return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;

}



/* Basic parameter sanity check used by both mbind() and set_mempolicy() */

static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)

{

	*flags = *mode & MPOL_MODE_FLAGS;

	*mode &= ~MPOL_MODE_FLAGS;

	if ((unsigned int)(*mode) >= MPOL_MAX)

		return -EINVAL;

	if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))

		return -EINVAL;



	return 0;

}



static long kernel_mbind(unsigned long start, unsigned long len,

			 unsigned long mode, const unsigned long __user *nmask,

			 unsigned long maxnode, unsigned int flags)

{

	unsigned short mode_flags;

	nodemask_t nodes;

	int lmode = mode;

	int err;

	unsigned short mode_flags;



	start = untagged_addr(start);

	mode_flags = mode & MPOL_MODE_FLAGS;

	mode &= ~MPOL_MODE_FLAGS;

	if (mode >= MPOL_MAX)

		return -EINVAL;

	if ((mode_flags & MPOL_F_STATIC_NODES) &&

	    (mode_flags & MPOL_F_RELATIVE_NODES))

		return -EINVAL;

	err = sanitize_mpol_flags(&lmode, &mode_flags);

	if (err)

		return err;



	err = get_nodes(&nodes, nmask, maxnode);

	if (err)

		return err;

	return do_mbind(start, len, mode, mode_flags, &nodes, flags);



	return do_mbind(start, len, lmode, mode_flags, &nodes, flags);

}



SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
@@ -1507,20 +1519,20 @@ SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, 
static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,

				 unsigned long maxnode)

{

	int err;

	unsigned short mode_flags;

	nodemask_t nodes;

	unsigned short flags;

	int lmode = mode;

	int err;



	err = sanitize_mpol_flags(&lmode, &mode_flags);

	if (err)

		return err;



	flags = mode & MPOL_MODE_FLAGS;

	mode &= ~MPOL_MODE_FLAGS;

	if ((unsigned int)mode >= MPOL_MAX)

		return -EINVAL;

	if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES))

		return -EINVAL;

	err = get_nodes(&nodes, nmask, maxnode);

	if (err)

		return err;

	return do_set_mempolicy(mode, flags, &nodes);



	return do_set_mempolicy(lmode, mode_flags, &nodes);

}



SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,