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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/admin-guide/device-mapper/dm-integrity.rst | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to 'Documentation/admin-guide/device-mapper/dm-integrity.rst')
-rw-r--r-- | Documentation/admin-guide/device-mapper/dm-integrity.rst | 292 |
1 files changed, 292 insertions, 0 deletions
diff --git a/Documentation/admin-guide/device-mapper/dm-integrity.rst b/Documentation/admin-guide/device-mapper/dm-integrity.rst new file mode 100644 index 000000000..8db172efa --- /dev/null +++ b/Documentation/admin-guide/device-mapper/dm-integrity.rst @@ -0,0 +1,292 @@ +============ +dm-integrity +============ + +The dm-integrity target emulates a block device that has additional +per-sector tags that can be used for storing integrity information. + +A general problem with storing integrity tags with every sector is that +writing the sector and the integrity tag must be atomic - i.e. in case of +crash, either both sector and integrity tag or none of them is written. + +To guarantee write atomicity, the dm-integrity target uses journal, it +writes sector data and integrity tags into a journal, commits the journal +and then copies the data and integrity tags to their respective location. + +The dm-integrity target can be used with the dm-crypt target - in this +situation the dm-crypt target creates the integrity data and passes them +to the dm-integrity target via bio_integrity_payload attached to the bio. +In this mode, the dm-crypt and dm-integrity targets provide authenticated +disk encryption - if the attacker modifies the encrypted device, an I/O +error is returned instead of random data. + +The dm-integrity target can also be used as a standalone target, in this +mode it calculates and verifies the integrity tag internally. In this +mode, the dm-integrity target can be used to detect silent data +corruption on the disk or in the I/O path. + +There's an alternate mode of operation where dm-integrity uses bitmap +instead of a journal. If a bit in the bitmap is 1, the corresponding +region's data and integrity tags are not synchronized - if the machine +crashes, the unsynchronized regions will be recalculated. The bitmap mode +is faster than the journal mode, because we don't have to write the data +twice, but it is also less reliable, because if data corruption happens +when the machine crashes, it may not be detected. + +When loading the target for the first time, the kernel driver will format +the device. But it will only format the device if the superblock contains +zeroes. If the superblock is neither valid nor zeroed, the dm-integrity +target can't be loaded. + +To use the target for the first time: + +1. overwrite the superblock with zeroes +2. load the dm-integrity target with one-sector size, the kernel driver + will format the device +3. unload the dm-integrity target +4. read the "provided_data_sectors" value from the superblock +5. load the dm-integrity target with the target size + "provided_data_sectors" +6. if you want to use dm-integrity with dm-crypt, load the dm-crypt target + with the size "provided_data_sectors" + + +Target arguments: + +1. the underlying block device + +2. the number of reserved sector at the beginning of the device - the + dm-integrity won't read of write these sectors + +3. the size of the integrity tag (if "-" is used, the size is taken from + the internal-hash algorithm) + +4. mode: + + D - direct writes (without journal) + in this mode, journaling is + not used and data sectors and integrity tags are written + separately. In case of crash, it is possible that the data + and integrity tag doesn't match. + J - journaled writes + data and integrity tags are written to the + journal and atomicity is guaranteed. In case of crash, + either both data and tag or none of them are written. The + journaled mode degrades write throughput twice because the + data have to be written twice. + B - bitmap mode - data and metadata are written without any + synchronization, the driver maintains a bitmap of dirty + regions where data and metadata don't match. This mode can + only be used with internal hash. + R - recovery mode - in this mode, journal is not replayed, + checksums are not checked and writes to the device are not + allowed. This mode is useful for data recovery if the + device cannot be activated in any of the other standard + modes. + +5. the number of additional arguments + +Additional arguments: + +journal_sectors:number + The size of journal, this argument is used only if formatting the + device. If the device is already formatted, the value from the + superblock is used. + +interleave_sectors:number + The number of interleaved sectors. This values is rounded down to + a power of two. If the device is already formatted, the value from + the superblock is used. + +meta_device:device + Don't interleave the data and metadata on the device. Use a + separate device for metadata. + +buffer_sectors:number + The number of sectors in one buffer. The value is rounded down to + a power of two. + + The tag area is accessed using buffers, the buffer size is + configurable. The large buffer size means that the I/O size will + be larger, but there could be less I/Os issued. + +journal_watermark:number + The journal watermark in percents. When the size of the journal + exceeds this watermark, the thread that flushes the journal will + be started. + +commit_time:number + Commit time in milliseconds. When this time passes, the journal is + written. The journal is also written immediately if the FLUSH + request is received. + +internal_hash:algorithm(:key) (the key is optional) + Use internal hash or crc. + When this argument is used, the dm-integrity target won't accept + integrity tags from the upper target, but it will automatically + generate and verify the integrity tags. + + You can use a crc algorithm (such as crc32), then integrity target + will protect the data against accidental corruption. + You can also use a hmac algorithm (for example + "hmac(sha256):0123456789abcdef"), in this mode it will provide + cryptographic authentication of the data without encryption. + + When this argument is not used, the integrity tags are accepted + from an upper layer target, such as dm-crypt. The upper layer + target should check the validity of the integrity tags. + +recalculate + Recalculate the integrity tags automatically. It is only valid + when using internal hash. + +journal_crypt:algorithm(:key) (the key is optional) + Encrypt the journal using given algorithm to make sure that the + attacker can't read the journal. You can use a block cipher here + (such as "cbc(aes)") or a stream cipher (for example "chacha20" + or "ctr(aes)"). + + The journal contains history of last writes to the block device, + an attacker reading the journal could see the last sector numbers + that were written. From the sector numbers, the attacker can infer + the size of files that were written. To protect against this + situation, you can encrypt the journal. + +journal_mac:algorithm(:key) (the key is optional) + Protect sector numbers in the journal from accidental or malicious + modification. To protect against accidental modification, use a + crc algorithm, to protect against malicious modification, use a + hmac algorithm with a key. + + This option is not needed when using internal-hash because in this + mode, the integrity of journal entries is checked when replaying + the journal. Thus, modified sector number would be detected at + this stage. + +block_size:number + The size of a data block in bytes. The larger the block size the + less overhead there is for per-block integrity metadata. + Supported values are 512, 1024, 2048 and 4096 bytes. If not + specified the default block size is 512 bytes. + +sectors_per_bit:number + In the bitmap mode, this parameter specifies the number of + 512-byte sectors that corresponds to one bitmap bit. + +bitmap_flush_interval:number + The bitmap flush interval in milliseconds. The metadata buffers + are synchronized when this interval expires. + +allow_discards + Allow block discard requests (a.k.a. TRIM) for the integrity device. + Discards are only allowed to devices using internal hash. + +fix_padding + Use a smaller padding of the tag area that is more + space-efficient. If this option is not present, large padding is + used - that is for compatibility with older kernels. + +fix_hmac + Improve security of internal_hash and journal_mac: + + - the section number is mixed to the mac, so that an attacker can't + copy sectors from one journal section to another journal section + - the superblock is protected by journal_mac + - a 16-byte salt stored in the superblock is mixed to the mac, so + that the attacker can't detect that two disks have the same hmac + key and also to disallow the attacker to move sectors from one + disk to another + +legacy_recalculate + Allow recalculating of volumes with HMAC keys. This is disabled by + default for security reasons - an attacker could modify the volume, + set recalc_sector to zero, and the kernel would not detect the + modification. + +The journal mode (D/J), buffer_sectors, journal_watermark, commit_time and +allow_discards can be changed when reloading the target (load an inactive +table and swap the tables with suspend and resume). The other arguments +should not be changed when reloading the target because the layout of disk +data depend on them and the reloaded target would be non-functional. + + +Status line: + +1. the number of integrity mismatches +2. provided data sectors - that is the number of sectors that the user + could use +3. the current recalculating position (or '-' if we didn't recalculate) + + +The layout of the formatted block device: + +* reserved sectors + (they are not used by this target, they can be used for + storing LUKS metadata or for other purpose), the size of the reserved + area is specified in the target arguments + +* superblock (4kiB) + * magic string - identifies that the device was formatted + * version + * log2(interleave sectors) + * integrity tag size + * the number of journal sections + * provided data sectors - the number of sectors that this target + provides (i.e. the size of the device minus the size of all + metadata and padding). The user of this target should not send + bios that access data beyond the "provided data sectors" limit. + * flags + SB_FLAG_HAVE_JOURNAL_MAC + - a flag is set if journal_mac is used + SB_FLAG_RECALCULATING + - recalculating is in progress + SB_FLAG_DIRTY_BITMAP + - journal area contains the bitmap of dirty + blocks + * log2(sectors per block) + * a position where recalculating finished +* journal + The journal is divided into sections, each section contains: + + * metadata area (4kiB), it contains journal entries + + - every journal entry contains: + + * logical sector (specifies where the data and tag should + be written) + * last 8 bytes of data + * integrity tag (the size is specified in the superblock) + + - every metadata sector ends with + + * mac (8-bytes), all the macs in 8 metadata sectors form a + 64-byte value. It is used to store hmac of sector + numbers in the journal section, to protect against a + possibility that the attacker tampers with sector + numbers in the journal. + * commit id + + * data area (the size is variable; it depends on how many journal + entries fit into the metadata area) + + - every sector in the data area contains: + + * data (504 bytes of data, the last 8 bytes are stored in + the journal entry) + * commit id + + To test if the whole journal section was written correctly, every + 512-byte sector of the journal ends with 8-byte commit id. If the + commit id matches on all sectors in a journal section, then it is + assumed that the section was written correctly. If the commit id + doesn't match, the section was written partially and it should not + be replayed. + +* one or more runs of interleaved tags and data. + Each run contains: + + * tag area - it contains integrity tags. There is one tag for each + sector in the data area + * data area - it contains data sectors. The number of data sectors + in one run must be a power of two. log2 of this value is stored + in the superblock. |