Commit 38bbca6b authored by David Howells's avatar David Howells Committed by Linus Torvalds
Browse files

keys: increase the payload size when instantiating a key 



Increase the size of a payload that can be used to instantiate a key in
add_key() and keyctl_instantiate_key().  This permits huge CIFS SPNEGO blobs
to be passed around.  The limit is raised to 1MB.  If kmalloc() can't allocate
a buffer of sufficient size, vmalloc() will be tried instead.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Paul Moore <paul.moore@hp.com>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Kevin Coffman <kwc@citi.umich.edu>
Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4220b7fe

security/keys/keyctl.c

+30 −8
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/capability.h>

#include <linux/string.h>

#include <linux/err.h>

#include <linux/vmalloc.h>

#include <asm/uaccess.h>

#include "internal.h"
@@ -62,9 +63,10 @@ asmlinkage long sys_add_key(const char __user *_type, 
	char type[32], *description;

	void *payload;

	long ret;

	bool vm;



	ret = -EINVAL;

	if (plen > 32767)

	if (plen > 1024 * 1024 - 1)

		goto error;



	/* draw all the data into kernel space */
@@ -81,11 +83,18 @@ asmlinkage long sys_add_key(const char __user *_type, 
	/* pull the payload in if one was supplied */

	payload = NULL;



	vm = false;

	if (_payload) {

		ret = -ENOMEM;

		payload = kmalloc(plen, GFP_KERNEL);

		if (!payload) {

			if (plen <= PAGE_SIZE)

				goto error2;

			vm = true;

			payload = vmalloc(plen);

			if (!payload)

				goto error2;

		}



		ret = -EFAULT;

		if (copy_from_user(payload, _payload, plen) != 0)
@@ -113,7 +122,10 @@ asmlinkage long sys_add_key(const char __user *_type, 


	key_ref_put(keyring_ref);

 error3:

	if (!vm)

		kfree(payload);

	else

		vfree(payload);

 error2:

	kfree(description);

 error:
@@ -821,9 +833,10 @@ long keyctl_instantiate_key(key_serial_t id, 
	key_ref_t keyring_ref;

	void *payload;

	long ret;

	bool vm = false;



	ret = -EINVAL;

	if (plen > 32767)

	if (plen > 1024 * 1024 - 1)

		goto error;



	/* the appropriate instantiation authorisation key must have been
@@ -843,8 +856,14 @@ long keyctl_instantiate_key(key_serial_t id, 
	if (_payload) {

		ret = -ENOMEM;

		payload = kmalloc(plen, GFP_KERNEL);

		if (!payload) {

			if (plen <= PAGE_SIZE)

				goto error;

			vm = true;

			payload = vmalloc(plen);

			if (!payload)

				goto error;

		}



		ret = -EFAULT;

		if (copy_from_user(payload, _payload, plen) != 0)
@@ -877,7 +896,10 @@ long keyctl_instantiate_key(key_serial_t id, 
	}



error2:

	if (!vm)

		kfree(payload);

	else

		vfree(payload);

error:

	return ret;

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