Skip to content

Commit

Permalink
---
Browse files Browse the repository at this point in the history
yaml
---
r: 9965
b: refs/heads/master
c: 7217cbc
h: refs/heads/master
i:
  9963: bb661d2
v: v3
  • Loading branch information
Trond Myklebust authored and Trond Myklebust committed Oct 13, 2005
1 parent 6bff273 commit 0192ee1
Show file tree
Hide file tree
Showing 828 changed files with 28,301 additions and 8,336 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 6cd7525a00f3b926e8bd2e402954ed3e09a8e924
refs/heads/master: 7217cbccbd0c620a6d234ebbe5e58d46d2188d0e
10 changes: 10 additions & 0 deletions trunk/Documentation/Changes
Original file line number Diff line number Diff line change
Expand Up @@ -237,6 +237,12 @@ udev
udev is a userspace application for populating /dev dynamically with
only entries for devices actually present. udev replaces devfs.

FUSE
----

Needs libfuse 2.4.0 or later. Absolute minimum is 2.3.0 but mount
options 'direct_io' and 'kernel_cache' won't work.

Networking
==========

Expand Down Expand Up @@ -390,6 +396,10 @@ udev
----
o <http://www.kernel.org/pub/linux/utils/kernel/hotplug/udev.html>

FUSE
----
o <http://sourceforge.net/projects/fuse>

Networking
**********

Expand Down
86 changes: 85 additions & 1 deletion trunk/Documentation/SubmittingPatches
Original file line number Diff line number Diff line change
Expand Up @@ -301,15 +301,99 @@ now, but you can do this to mark internal company procedures or just
point out some special detail about the sign-off.


12) The canonical patch format

12) More references for submitting patches
The canonical patch subject line is:

Subject: [PATCH 001/123] subsystem: summary phrase

The canonical patch message body contains the following:

- A "from" line specifying the patch author.

- An empty line.

- The body of the explanation, which will be copied to the
permanent changelog to describe this patch.

- The "Signed-off-by:" lines, described above, which will
also go in the changelog.

- A marker line containing simply "---".

- Any additional comments not suitable for the changelog.

- The actual patch (diff output).

The Subject line format makes it very easy to sort the emails
alphabetically by subject line - pretty much any email reader will
support that - since because the sequence number is zero-padded,
the numerical and alphabetic sort is the same.

The "subsystem" in the email's Subject should identify which
area or subsystem of the kernel is being patched.

The "summary phrase" in the email's Subject should concisely
describe the patch which that email contains. The "summary
phrase" should not be a filename. Do not use the same "summary
phrase" for every patch in a whole patch series.

Bear in mind that the "summary phrase" of your email becomes
a globally-unique identifier for that patch. It propagates
all the way into the git changelog. The "summary phrase" may
later be used in developer discussions which refer to the patch.
People will want to google for the "summary phrase" to read
discussion regarding that patch.

A couple of example Subjects:

Subject: [patch 2/5] ext2: improve scalability of bitmap searching
Subject: [PATCHv2 001/207] x86: fix eflags tracking

The "from" line must be the very first line in the message body,
and has the form:

From: Original Author <author@example.com>

The "from" line specifies who will be credited as the author of the
patch in the permanent changelog. If the "from" line is missing,
then the "From:" line from the email header will be used to determine
the patch author in the changelog.

The explanation body will be committed to the permanent source
changelog, so should make sense to a competent reader who has long
since forgotten the immediate details of the discussion that might
have led to this patch.

The "---" marker line serves the essential purpose of marking for patch
handling tools where the changelog message ends.

One good use for the additional comments after the "---" marker is for
a diffstat, to show what files have changed, and the number of inserted
and deleted lines per file. A diffstat is especially useful on bigger
patches. Other comments relevant only to the moment or the maintainer,
not suitable for the permanent changelog, should also go here.

See more details on the proper patch format in the following
references.


13) More references for submitting patches

Andrew Morton, "The perfect patch" (tpp).
<http://www.zip.com.au/~akpm/linux/patches/stuff/tpp.txt>

Jeff Garzik, "Linux kernel patch submission format."
<http://linux.yyz.us/patch-format.html>

Greg KH, "How to piss off a kernel subsystem maintainer"
<http://www.kroah.com/log/2005/03/31/>

Kernel Documentation/CodingStyle
<http://sosdg.org/~coywolf/lxr/source/Documentation/CodingStyle>

Linus Torvald's mail on the canonical patch format:
<http://lkml.org/lkml/2005/4/7/183>


-----------------------------------
Expand Down
38 changes: 28 additions & 10 deletions trunk/Documentation/dell_rbu.txt
Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ The driver load creates the following directories under the /sys file system.
/sys/class/firmware/dell_rbu/data
/sys/devices/platform/dell_rbu/image_type
/sys/devices/platform/dell_rbu/data
/sys/devices/platform/dell_rbu/packet_size

The driver supports two types of update mechanism; monolithic and packetized.
These update mechanism depends upon the BIOS currently running on the system.
Expand All @@ -47,8 +48,26 @@ By default the driver uses monolithic memory for the update type. This can be
changed to packets during the driver load time by specifying the load
parameter image_type=packet. This can also be changed later as below
echo packet > /sys/devices/platform/dell_rbu/image_type
Also echoing either mono ,packet or init in to image_type will free up the
memory allocated by the driver.

In packet update mode the packet size has to be given before any packets can
be downloaded. It is done as below
echo XXXX > /sys/devices/platform/dell_rbu/packet_size
In the packet update mechanism, the user neesd to create a new file having
packets of data arranged back to back. It can be done as follows
The user creates packets header, gets the chunk of the BIOS image and
placs it next to the packetheader; now, the packetheader + BIOS image chunk
added to geather should match the specified packet_size. This makes one
packet, the user needs to create more such packets out of the entire BIOS
image file and then arrange all these packets back to back in to one single
file.
This file is then copied to /sys/class/firmware/dell_rbu/data.
Once this file gets to the driver, the driver extracts packet_size data from
the file and spreads it accross the physical memory in contiguous packet_sized
space.
This method makes sure that all the packets get to the driver in a single operation.

In monolithic update the user simply get the BIOS image (.hdr file) and copies
to the data file as is without any change to the BIOS image itself.

Do the steps below to download the BIOS image.
1) echo 1 > /sys/class/firmware/dell_rbu/loading
Expand All @@ -58,23 +77,22 @@ Do the steps below to download the BIOS image.
The /sys/class/firmware/dell_rbu/ entries will remain till the following is
done.
echo -1 > /sys/class/firmware/dell_rbu/loading.
Until this step is completed the drivr cannot be unloaded.
Until this step is completed the driver cannot be unloaded.
Also echoing either mono ,packet or init in to image_type will free up the
memory allocated by the driver.

If an user by accident executes steps 1 and 3 above without executing step 2;
it will make the /sys/class/firmware/dell_rbu/ entries to disappear.
The entries can be recreated by doing the following
echo init > /sys/devices/platform/dell_rbu/image_type
NOTE: echoing init in image_type does not change it original value.

Also the driver provides /sys/devices/platform/dell_rbu/data readonly file to
read back the image downloaded. This is useful in case of packet update
mechanism where the above steps 1,2,3 will repeated for every packet.
By reading the /sys/devices/platform/dell_rbu/data file all packet data
downloaded can be verified in a single file.
The packets are arranged in this file one after the other in a FIFO order.
read back the image downloaded.

NOTE:
This driver requires a patch for firmware_class.c which has the addition
of request_firmware_nowait_nohotplug function to wortk
This driver requires a patch for firmware_class.c which has the modified
request_firmware_nowait function.
Also after updating the BIOS image an user mdoe application neeeds to execute
code which message the BIOS update request to the BIOS. So on the next reboot
the BIOS knows about the new image downloaded and it updates it self.
Expand Down
161 changes: 161 additions & 0 deletions trunk/Documentation/keys-request-key.txt
Original file line number Diff line number Diff line change
@@ -0,0 +1,161 @@
===================
KEY REQUEST SERVICE
===================

The key request service is part of the key retention service (refer to
Documentation/keys.txt). This document explains more fully how that the
requesting algorithm works.

The process starts by either the kernel requesting a service by calling
request_key():

struct key *request_key(const struct key_type *type,
const char *description,
const char *callout_string);

Or by userspace invoking the request_key system call:

key_serial_t request_key(const char *type,
const char *description,
const char *callout_info,
key_serial_t dest_keyring);

The main difference between the two access points is that the in-kernel
interface does not need to link the key to a keyring to prevent it from being
immediately destroyed. The kernel interface returns a pointer directly to the
key, and it's up to the caller to destroy the key.

The userspace interface links the key to a keyring associated with the process
to prevent the key from going away, and returns the serial number of the key to
the caller.


===========
THE PROCESS
===========

A request proceeds in the following manner:

(1) Process A calls request_key() [the userspace syscall calls the kernel
interface].

(2) request_key() searches the process's subscribed keyrings to see if there's
a suitable key there. If there is, it returns the key. If there isn't, and
callout_info is not set, an error is returned. Otherwise the process
proceeds to the next step.

(3) request_key() sees that A doesn't have the desired key yet, so it creates
two things:

(a) An uninstantiated key U of requested type and description.

(b) An authorisation key V that refers to key U and notes that process A
is the context in which key U should be instantiated and secured, and
from which associated key requests may be satisfied.

(4) request_key() then forks and executes /sbin/request-key with a new session
keyring that contains a link to auth key V.

(5) /sbin/request-key execs an appropriate program to perform the actual
instantiation.

(6) The program may want to access another key from A's context (say a
Kerberos TGT key). It just requests the appropriate key, and the keyring
search notes that the session keyring has auth key V in its bottom level.

This will permit it to then search the keyrings of process A with the
UID, GID, groups and security info of process A as if it was process A,
and come up with key W.

(7) The program then does what it must to get the data with which to
instantiate key U, using key W as a reference (perhaps it contacts a
Kerberos server using the TGT) and then instantiates key U.

(8) Upon instantiating key U, auth key V is automatically revoked so that it
may not be used again.

(9) The program then exits 0 and request_key() deletes key V and returns key
U to the caller.

This also extends further. If key W (step 5 above) didn't exist, key W would be
created uninstantiated, another auth key (X) would be created [as per step 3]
and another copy of /sbin/request-key spawned [as per step 4]; but the context
specified by auth key X will still be process A, as it was in auth key V.

This is because process A's keyrings can't simply be attached to
/sbin/request-key at the appropriate places because (a) execve will discard two
of them, and (b) it requires the same UID/GID/Groups all the way through.


======================
NEGATIVE INSTANTIATION
======================

Rather than instantiating a key, it is possible for the possessor of an
authorisation key to negatively instantiate a key that's under construction.
This is a short duration placeholder that causes any attempt at re-requesting
the key whilst it exists to fail with error ENOKEY.

This is provided to prevent excessive repeated spawning of /sbin/request-key
processes for a key that will never be obtainable.

Should the /sbin/request-key process exit anything other than 0 or die on a
signal, the key under construction will be automatically negatively
instantiated for a short amount of time.


====================
THE SEARCH ALGORITHM
====================

A search of any particular keyring proceeds in the following fashion:

(1) When the key management code searches for a key (keyring_search_aux) it
firstly calls key_permission(SEARCH) on the keyring it's starting with,
if this denies permission, it doesn't search further.

(2) It considers all the non-keyring keys within that keyring and, if any key
matches the criteria specified, calls key_permission(SEARCH) on it to see
if the key is allowed to be found. If it is, that key is returned; if
not, the search continues, and the error code is retained if of higher
priority than the one currently set.

(3) It then considers all the keyring-type keys in the keyring it's currently
searching. It calls key_permission(SEARCH) on each keyring, and if this
grants permission, it recurses, executing steps (2) and (3) on that
keyring.

The process stops immediately a valid key is found with permission granted to
use it. Any error from a previous match attempt is discarded and the key is
returned.

When search_process_keyrings() is invoked, it performs the following searches
until one succeeds:

(1) If extant, the process's thread keyring is searched.

(2) If extant, the process's process keyring is searched.

(3) The process's session keyring is searched.

(4) If the process has a request_key() authorisation key in its session
keyring then:

(a) If extant, the calling process's thread keyring is searched.

(b) If extant, the calling process's process keyring is searched.

(c) The calling process's session keyring is searched.

The moment one succeeds, all pending errors are discarded and the found key is
returned.

Only if all these fail does the whole thing fail with the highest priority
error. Note that several errors may have come from LSM.

The error priority is:

EKEYREVOKED > EKEYEXPIRED > ENOKEY

EACCES/EPERM are only returned on a direct search of a specific keyring where
the basal keyring does not grant Search permission.
Loading

0 comments on commit 0192ee1

Please sign in to comment.