Core
----
- Rework the sendpage & splice implementations. Instead of feeding
data into sockets page by page extend sendmsg handlers to support
taking a reference on the data, controlled by a new flag called
MSG_SPLICE_PAGES. Rework the handling of unexpected-end-of-file
to invoke an additional callback instead of trying to predict what
the right combination of MORE/NOTLAST flags is.
Remove the MSG_SENDPAGE_NOTLAST flag completely.
- Implement SCM_PIDFD, a new type of CMSG type analogous to
SCM_CREDENTIALS, but it contains pidfd instead of plain pid.
- Enable socket busy polling with CONFIG_RT.
- Improve reliability and efficiency of reporting for ref_tracker.
- Auto-generate a user space C library for various Netlink families.
Protocols
---------
- Allow TCP to shrink the advertised window when necessary, prevent
sk_rcvbuf auto-tuning from growing the window all the way up to
tcp_rmem[2].
- Use per-VMA locking for "page-flipping" TCP receive zerocopy.
- Prepare TCP for device-to-device data transfers, by making sure
that payloads are always attached to skbs as page frags.
- Make the backoff time for the first N TCP SYN retransmissions
linear. Exponential backoff is unnecessarily conservative.
- Create a new MPTCP getsockopt to retrieve all info (MPTCP_FULL_INFO).
- Avoid waking up applications using TLS sockets until we have
a full record.
- Allow using kernel memory for protocol ioctl callbacks, paving
the way to issuing ioctls over io_uring.
- Add nolocalbypass option to VxLAN, forcing packets to be fully
encapsulated even if they are destined for a local IP address.
- Make TCPv4 use consistent hash in TIME_WAIT and SYN_RECV. Ensure
in-kernel ECMP implementation (e.g. Open vSwitch) select the same
link for all packets. Support L4 symmetric hashing in Open vSwitch.
- PPPoE: make number of hash bits configurable.
- Allow DNS to be overwritten by DHCPACK in the in-kernel DHCP client
(ipconfig).
- Add layer 2 miss indication and filtering, allowing higher layers
(e.g. ACL filters) to make forwarding decisions based on whether
packet matched forwarding state in lower devices (bridge).
- Support matching on Connectivity Fault Management (CFM) packets.
- Hide the "link becomes ready" IPv6 messages by demoting their
printk level to debug.
- HSR: don't enable promiscuous mode if device offloads the proto.
- Support active scanning in IEEE 802.15.4.
- Continue work on Multi-Link Operation for WiFi 7.
BPF
---
- Add precision propagation for subprogs and callbacks. This allows
maintaining verification efficiency when subprograms are used,
or in fact passing the verifier at all for complex programs,
especially those using open-coded iterators.
- Improve BPF's {g,s}setsockopt() length handling. Previously BPF
assumed the length is always equal to the amount of written data.
But some protos allow passing a NULL buffer to discover what
the output buffer *should* be, without writing anything.
- Accept dynptr memory as memory arguments passed to helpers.
- Add routing table ID to bpf_fib_lookup BPF helper.
- Support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands.
- Drop bpf_capable() check in BPF_MAP_FREEZE command (used to mark
maps as read-only).
- Show target_{obj,btf}_id in tracing link fdinfo.
- Addition of several new kfuncs (most of the names are self-explanatory):
- Add a set of new dynptr kfuncs: bpf_dynptr_adjust(),
bpf_dynptr_is_null(), bpf_dynptr_is_rdonly(), bpf_dynptr_size()
and bpf_dynptr_clone().
- bpf_task_under_cgroup()
- bpf_sock_destroy() - force closing sockets
- bpf_cpumask_first_and(), rework bpf_cpumask_any*() kfuncs
Netfilter
---------
- Relax set/map validation checks in nf_tables. Allow checking
presence of an entry in a map without using the value.
- Increase ip_vs_conn_tab_bits range for 64BIT builds.
- Allow updating size of a set.
- Improve NAT tuple selection when connection is closing.
Driver API
----------
- Integrate netdev with LED subsystem, to allow configuring HW
"offloaded" blinking of LEDs based on link state and activity
(i.e. packets coming in and out).
- Support configuring rate selection pins of SFP modules.
- Factor Clause 73 auto-negotiation code out of the drivers, provide
common helper routines.
- Add more fool-proof helpers for managing lifetime of MDIO devices
associated with the PCS layer.
- Allow drivers to report advanced statistics related to Time Aware
scheduler offload (taprio).
- Allow opting out of VF statistics in link dump, to allow more VFs
to fit into the message.
- Split devlink instance and devlink port operations.
New hardware / drivers
----------------------
- Ethernet:
- Synopsys EMAC4 IP support (stmmac)
- Marvell 88E6361 8 port (5x1GE + 3x2.5GE) switches
- Marvell 88E6250 7 port switches
- Microchip LAN8650/1 Rev.B0 PHYs
- MediaTek MT7981/MT7988 built-in 1GE PHY driver
- WiFi:
- Realtek RTL8192FU, 2.4 GHz, b/g/n mode, 2T2R, 300 Mbps
- Realtek RTL8723DS (SDIO variant)
- Realtek RTL8851BE
- CAN:
- Fintek F81604
Drivers
-------
- Ethernet NICs:
- Intel (100G, ice):
- support dynamic interrupt allocation
- use meta data match instead of VF MAC addr on slow-path
- nVidia/Mellanox:
- extend link aggregation to handle 4, rather than just 2 ports
- spawn sub-functions without any features by default
- OcteonTX2:
- support HTB (Tx scheduling/QoS) offload
- make RSS hash generation configurable
- support selecting Rx queue using TC filters
- Wangxun (ngbe/txgbe):
- add basic Tx/Rx packet offloads
- add phylink support (SFP/PCS control)
- Freescale/NXP (enetc):
- report TAPRIO packet statistics
- Solarflare/AMD:
- support matching on IP ToS and UDP source port of outer header
- VxLAN and GENEVE tunnel encapsulation over IPv4 or IPv6
- add devlink dev info support for EF10
- Virtual NICs:
- Microsoft vNIC:
- size the Rx indirection table based on requested configuration
- support VLAN tagging
- Amazon vNIC:
- try to reuse Rx buffers if not fully consumed, useful for ARM
servers running with 16kB pages
- Google vNIC:
- support TCP segmentation of >64kB frames
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- enable USXGMII (88E6191X)
- Microchip:
- lan966x: add support for Egress Stage 0 ACL engine
- lan966x: support mapping packet priority to internal switch
priority (based on PCP or DSCP)
- Ethernet PHYs:
- Broadcom PHYs:
- support for Wake-on-LAN for BCM54210E/B50212E
- report LPI counter
- Microsemi PHYs: support RGMII delay configuration (VSC85xx)
- Micrel PHYs: receive timestamp in the frame (LAN8841)
- Realtek PHYs: support optional external PHY clock
- Altera TSE PCS: merge the driver into Lynx PCS which it is
a variant of
- CAN: Kvaser PCIEcan:
- support packet timestamping
- WiFi:
- Intel (iwlwifi):
- major update for new firmware and Multi-Link Operation (MLO)
- configuration rework to drop test devices and split
the different families
- support for segmented PNVM images and power tables
- new vendor entries for PPAG (platform antenna gain) feature
- Qualcomm 802.11ax (ath11k):
- Multiple Basic Service Set Identifier (MBSSID) and
Enhanced MBSSID Advertisement (EMA) support in AP mode
- support factory test mode
- RealTek (rtw89):
- add RSSI based antenna diversity
- support U-NII-4 channels on 5 GHz band
- RealTek (rtl8xxxu):
- AP mode support for 8188f
- support USB RX aggregation for the newer chips
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-next-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking changes from Jakub Kicinski:
"WiFi 7 and sendpage changes are the biggest pieces of work for this
release. The latter will definitely require fixes but I think that we
got it to a reasonable point.
Core:
- Rework the sendpage & splice implementations
Instead of feeding data into sockets page by page extend sendmsg
handlers to support taking a reference on the data, controlled by a
new flag called MSG_SPLICE_PAGES
Rework the handling of unexpected-end-of-file to invoke an
additional callback instead of trying to predict what the right
combination of MORE/NOTLAST flags is
Remove the MSG_SENDPAGE_NOTLAST flag completely
- Implement SCM_PIDFD, a new type of CMSG type analogous to
SCM_CREDENTIALS, but it contains pidfd instead of plain pid
- Enable socket busy polling with CONFIG_RT
- Improve reliability and efficiency of reporting for ref_tracker
- Auto-generate a user space C library for various Netlink families
Protocols:
- Allow TCP to shrink the advertised window when necessary, prevent
sk_rcvbuf auto-tuning from growing the window all the way up to
tcp_rmem[2]
- Use per-VMA locking for "page-flipping" TCP receive zerocopy
- Prepare TCP for device-to-device data transfers, by making sure
that payloads are always attached to skbs as page frags
- Make the backoff time for the first N TCP SYN retransmissions
linear. Exponential backoff is unnecessarily conservative
- Create a new MPTCP getsockopt to retrieve all info
(MPTCP_FULL_INFO)
- Avoid waking up applications using TLS sockets until we have a full
record
- Allow using kernel memory for protocol ioctl callbacks, paving the
way to issuing ioctls over io_uring
- Add nolocalbypass option to VxLAN, forcing packets to be fully
encapsulated even if they are destined for a local IP address
- Make TCPv4 use consistent hash in TIME_WAIT and SYN_RECV. Ensure
in-kernel ECMP implementation (e.g. Open vSwitch) select the same
link for all packets. Support L4 symmetric hashing in Open vSwitch
- PPPoE: make number of hash bits configurable
- Allow DNS to be overwritten by DHCPACK in the in-kernel DHCP client
(ipconfig)
- Add layer 2 miss indication and filtering, allowing higher layers
(e.g. ACL filters) to make forwarding decisions based on whether
packet matched forwarding state in lower devices (bridge)
- Support matching on Connectivity Fault Management (CFM) packets
- Hide the "link becomes ready" IPv6 messages by demoting their
printk level to debug
- HSR: don't enable promiscuous mode if device offloads the proto
- Support active scanning in IEEE 802.15.4
- Continue work on Multi-Link Operation for WiFi 7
BPF:
- Add precision propagation for subprogs and callbacks. This allows
maintaining verification efficiency when subprograms are used, or
in fact passing the verifier at all for complex programs,
especially those using open-coded iterators
- Improve BPF's {g,s}setsockopt() length handling. Previously BPF
assumed the length is always equal to the amount of written data.
But some protos allow passing a NULL buffer to discover what the
output buffer *should* be, without writing anything
- Accept dynptr memory as memory arguments passed to helpers
- Add routing table ID to bpf_fib_lookup BPF helper
- Support O_PATH FDs in BPF_OBJ_PIN and BPF_OBJ_GET commands
- Drop bpf_capable() check in BPF_MAP_FREEZE command (used to mark
maps as read-only)
- Show target_{obj,btf}_id in tracing link fdinfo
- Addition of several new kfuncs (most of the names are
self-explanatory):
- Add a set of new dynptr kfuncs: bpf_dynptr_adjust(),
bpf_dynptr_is_null(), bpf_dynptr_is_rdonly(), bpf_dynptr_size()
and bpf_dynptr_clone().
- bpf_task_under_cgroup()
- bpf_sock_destroy() - force closing sockets
- bpf_cpumask_first_and(), rework bpf_cpumask_any*() kfuncs
Netfilter:
- Relax set/map validation checks in nf_tables. Allow checking
presence of an entry in a map without using the value
- Increase ip_vs_conn_tab_bits range for 64BIT builds
- Allow updating size of a set
- Improve NAT tuple selection when connection is closing
Driver API:
- Integrate netdev with LED subsystem, to allow configuring HW
"offloaded" blinking of LEDs based on link state and activity
(i.e. packets coming in and out)
- Support configuring rate selection pins of SFP modules
- Factor Clause 73 auto-negotiation code out of the drivers, provide
common helper routines
- Add more fool-proof helpers for managing lifetime of MDIO devices
associated with the PCS layer
- Allow drivers to report advanced statistics related to Time Aware
scheduler offload (taprio)
- Allow opting out of VF statistics in link dump, to allow more VFs
to fit into the message
- Split devlink instance and devlink port operations
New hardware / drivers:
- Ethernet:
- Synopsys EMAC4 IP support (stmmac)
- Marvell 88E6361 8 port (5x1GE + 3x2.5GE) switches
- Marvell 88E6250 7 port switches
- Microchip LAN8650/1 Rev.B0 PHYs
- MediaTek MT7981/MT7988 built-in 1GE PHY driver
- WiFi:
- Realtek RTL8192FU, 2.4 GHz, b/g/n mode, 2T2R, 300 Mbps
- Realtek RTL8723DS (SDIO variant)
- Realtek RTL8851BE
- CAN:
- Fintek F81604
Drivers:
- Ethernet NICs:
- Intel (100G, ice):
- support dynamic interrupt allocation
- use meta data match instead of VF MAC addr on slow-path
- nVidia/Mellanox:
- extend link aggregation to handle 4, rather than just 2 ports
- spawn sub-functions without any features by default
- OcteonTX2:
- support HTB (Tx scheduling/QoS) offload
- make RSS hash generation configurable
- support selecting Rx queue using TC filters
- Wangxun (ngbe/txgbe):
- add basic Tx/Rx packet offloads
- add phylink support (SFP/PCS control)
- Freescale/NXP (enetc):
- report TAPRIO packet statistics
- Solarflare/AMD:
- support matching on IP ToS and UDP source port of outer
header
- VxLAN and GENEVE tunnel encapsulation over IPv4 or IPv6
- add devlink dev info support for EF10
- Virtual NICs:
- Microsoft vNIC:
- size the Rx indirection table based on requested
configuration
- support VLAN tagging
- Amazon vNIC:
- try to reuse Rx buffers if not fully consumed, useful for ARM
servers running with 16kB pages
- Google vNIC:
- support TCP segmentation of >64kB frames
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- enable USXGMII (88E6191X)
- Microchip:
- lan966x: add support for Egress Stage 0 ACL engine
- lan966x: support mapping packet priority to internal switch
priority (based on PCP or DSCP)
- Ethernet PHYs:
- Broadcom PHYs:
- support for Wake-on-LAN for BCM54210E/B50212E
- report LPI counter
- Microsemi PHYs: support RGMII delay configuration (VSC85xx)
- Micrel PHYs: receive timestamp in the frame (LAN8841)
- Realtek PHYs: support optional external PHY clock
- Altera TSE PCS: merge the driver into Lynx PCS which it is a
variant of
- CAN: Kvaser PCIEcan:
- support packet timestamping
- WiFi:
- Intel (iwlwifi):
- major update for new firmware and Multi-Link Operation (MLO)
- configuration rework to drop test devices and split the
different families
- support for segmented PNVM images and power tables
- new vendor entries for PPAG (platform antenna gain) feature
- Qualcomm 802.11ax (ath11k):
- Multiple Basic Service Set Identifier (MBSSID) and Enhanced
MBSSID Advertisement (EMA) support in AP mode
- support factory test mode
- RealTek (rtw89):
- add RSSI based antenna diversity
- support U-NII-4 channels on 5 GHz band
- RealTek (rtl8xxxu):
- AP mode support for 8188f
- support USB RX aggregation for the newer chips"
* tag 'net-next-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1602 commits)
net: scm: introduce and use scm_recv_unix helper
af_unix: Skip SCM_PIDFD if scm->pid is NULL.
net: lan743x: Simplify comparison
netlink: Add __sock_i_ino() for __netlink_diag_dump().
net: dsa: avoid suspicious RCU usage for synced VLAN-aware MAC addresses
Revert "af_unix: Call scm_recv() only after scm_set_cred()."
phylink: ReST-ify the phylink_pcs_neg_mode() kdoc
libceph: Partially revert changes to support MSG_SPLICE_PAGES
net: phy: mscc: fix packet loss due to RGMII delays
net: mana: use vmalloc_array and vcalloc
net: enetc: use vmalloc_array and vcalloc
ionic: use vmalloc_array and vcalloc
pds_core: use vmalloc_array and vcalloc
gve: use vmalloc_array and vcalloc
octeon_ep: use vmalloc_array and vcalloc
net: usb: qmi_wwan: add u-blox 0x1312 composition
perf trace: fix MSG_SPLICE_PAGES build error
ipvlan: Fix return value of ipvlan_queue_xmit()
netfilter: nf_tables: fix underflow in chain reference counter
netfilter: nf_tables: unbind non-anonymous set if rule construction fails
...
Check for -EFAULT instead of wrapping the check in an ret < 0 block.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230614140341.521331-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
copy_splice_read calls into ->read_iter to read the data, which already
calls file_accessed.
Fixes: 33b3b04154 ("splice: Add a func to do a splice from an O_DIRECT file without ITER_PIPE")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: David Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/20230614140341.521331-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
splice_to_socket() assumes that a pipe_buffer won't hold more than a single
page of data - but this assumption can be violated by skb_splice_bits()
when it splices from a socket into a pipe.
The problem is that splice_to_socket() doesn't advance the pipe_buffer
length and offset when transcribing from the pipe buf into a bio_vec, so if
the buf is >PAGE_SIZE, it keeps repeating the same initial chunk and
doesn't advance the tail index. It then subtracts this from "remain" and
overcounts the amount of data to be sent.
The cleanup phase then tries to overclean the pipe, hits an unused pipe buf
and a NULL-pointer dereference occurs.
Fix this by not restricting the bio_vec size to PAGE_SIZE and instead
transcribing the entirety of each pipe_buffer into a single bio_vec and
advancing the tail index if remain hasn't hit zero yet.
Large bio_vecs will then be split up by iterator functions such as
iov_iter_extract_pages().
This resulted in a KASAN report looking like:
general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
...
RIP: 0010:pipe_buf_release include/linux/pipe_fs_i.h:203 [inline]
RIP: 0010:splice_to_socket+0xa91/0xe30 fs/splice.c:933
Fixes: 2dc334f1a6 ("splice, net: Use sendmsg(MSG_SPLICE_PAGES) rather than ->sendpage()")
Reported-by: syzbot+f9e28a23426ac3b24f20@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/0000000000000900e905fdeb8e39@google.com/
Tested-by: syzbot+f9e28a23426ac3b24f20@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
cc: David Ahern <dsahern@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Christian Brauner <brauner@kernel.org>
cc: Alexander Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/1428985.1686737388@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
splice_direct_to_actor() doesn't manage SPLICE_F_MORE correctly[1] - and,
as a result, it incorrectly signals/fails to signal MSG_MORE when splicing
to a socket. The problem I'm seeing happens when a short splice occurs
because we got a short read due to hitting the EOF on a file: as the length
read (read_len) is less than the remaining size to be spliced (len),
SPLICE_F_MORE (and thus MSG_MORE) is set.
The issue is that, for the moment, we have no way to know *why* the short
read occurred and so can't make a good decision on whether we *should* keep
MSG_MORE set.
MSG_SENDPAGE_NOTLAST was added to work around this, but that is also set
incorrectly under some circumstances - for example if a short read fills a
single pipe_buffer, but the next read would return more (seqfile can do
this).
This was observed with the multi_chunk_sendfile tests in the tls kselftest
program. Some of those tests would hang and time out when the last chunk
of file was less than the sendfile request size:
build/kselftest/net/tls -r tls.12_aes_gcm.multi_chunk_sendfile
This has been observed before[2] and worked around in AF_TLS[3].
Fix this by making splice_direct_to_actor() always signal SPLICE_F_MORE if
we haven't yet hit the requested operation size. SPLICE_F_MORE remains
signalled if the user passed it in to splice() but otherwise gets cleared
when we've read sufficient data to fulfill the request.
If, however, we get a premature EOF from ->splice_read(), have sent at
least one byte and SPLICE_F_MORE was not set by the caller, ->splice_eof()
will be invoked.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Linus Torvalds <torvalds@linux-foundation.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: David Hildenbrand <david@redhat.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Boris Pismenny <borisp@nvidia.com>
cc: John Fastabend <john.fastabend@gmail.com>
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/499791.1685485603@warthog.procyon.org.uk/ [1]
Link: https://lore.kernel.org/r/1591392508-14592-1-git-send-email-pooja.trivedi@stackpath.com/ [2]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=d452d48b9f8b1a7f8152d33ef52cfd7fe1735b0a [3]
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add an optional method, ->splice_eof(), to allow splice to indicate the
premature termination of a splice to struct file_operations and struct
proto_ops.
This is called if sendfile() or splice() encounters all of the following
conditions inside splice_direct_to_actor():
(1) the user did not set SPLICE_F_MORE (splice only), and
(2) an EOF condition occurred (->splice_read() returned 0), and
(3) we haven't read enough to fulfill the request (ie. len > 0 still), and
(4) we have already spliced at least one byte.
A further patch will modify the behaviour of SPLICE_F_MORE to always be
passed to the actor if either the user set it or we haven't yet read
sufficient data to fulfill the request.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: David Hildenbrand <david@redhat.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Boris Pismenny <borisp@nvidia.com>
cc: John Fastabend <john.fastabend@gmail.com>
cc: linux-mm@kvack.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Replace generic_splice_sendpage() + splice_from_pipe + pipe_to_sendpage()
with a net-specific handler, splice_to_socket(), that calls sendmsg() with
MSG_SPLICE_PAGES set instead of calling ->sendpage().
MSG_MORE is used to indicate if the sendmsg() is expected to be followed
with more data.
This allows multiple pipe-buffer pages to be passed in a single call in a
BVEC iterator, allowing the processing to be pushed down to a loop in the
protocol driver. This helps pave the way for passing multipage folios down
too.
Protocols that haven't been converted to handle MSG_SPLICE_PAGES yet should
just ignore it and do a normal sendmsg() for now - although that may be a
bit slower as it may copy everything.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Remove generic_file_splice_read() as it has been replaced with calls to
filemap_splice_read() and copy_splice_read().
With this, ITER_PIPE is no longer used.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Steve French <smfrench@gmail.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-cifs@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-30-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Make a read splice from a file descriptor that's open O_DIRECT use
copy_splice_read() to do the reading as filemap_splice_read() is unlikely
to find any pagecache to splice.
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Jens Axboe <axboe@kernel.dk>
cc: linux-fsdevel@vger.kernel.org
cc: linux-block@vger.kernel.org
cc: linux-mm@kvack.org
Link: https://lore.kernel.org/r/20230522135018.2742245-8-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Do a couple of cleanups to copy_splice_read():
(1) Cast to struct page **, not void *.
(2) Simplify the calculation of the number of pages to keep/reclaim in
copy_splice_read().
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christian Brauner <brauner@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230522135018.2742245-5-dhowells@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'pipe-nonblock-2023-05-06' of git://git.kernel.dk/linux
Pull nonblocking pipe io_uring support from Jens Axboe:
"Here's the revised edition of the FMODE_NOWAIT support for pipes, in
which we just flag it as such supporting FMODE_NOWAIT unconditionally,
but clear it if we ever end up using splice/vmsplice on the pipe.
The pipe read/write side is perfectly fine for nonblocking IO, however
splice and vmsplice can potentially wait for IO with the pipe lock
held"
* tag 'pipe-nonblock-2023-05-06' of git://git.kernel.dk/linux:
pipe: set FMODE_NOWAIT on pipes
splice: clear FMODE_NOWAIT on file if splice/vmsplice is used
In preparation for pipes setting FMODE_NOWAIT on pipes to indicate that
RWF_NOWAIT/IOCB_NOWAIT is fully supported, have splice and vmsplice
clear that file flag. Splice holds the pipe lock around IO and cannot
easily be refactored to avoid that, as splice and pipes are inherently
tied together.
By clearing FMODE_NOWAIT if splice is being used on a pipe, other users
of the pipe will know that the pipe is no longer safe for RWF_NOWAIT
and friends.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
The fsnotify ACCESS and MODIFY event are missing when manipulating a file
with splice(2).
Signed-off-by: Chung-Chiang Cheng <cccheng@synology.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Message-Id: <20230322062519.409752-1-cccheng@synology.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
The variable ret belongs to redundant assignment and can be deleted.
fs/splice.c:940:2: warning: Value stored to 'ret' is never read.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Link: https://bugzilla.openanolis.cn/show_bug.cgi?id=4406
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
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Merge tag '6.3-rc-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6
Pull cifs client updates from Steve French:
"The largest subset of this is from David Howells et al: making the
cifs/smb3 driver pass iov_iters down to the lowest layers, directly to
the network transport rather than passing lists of pages around,
helping multiple areas:
- Pin user pages, thereby fixing the race between concurrent DIO read
and fork, where the pages containing the DIO read buffer may end up
belonging to the child process and not the parent - with the result
that the parent might not see the retrieved data.
- cifs shouldn't take refs on pages extracted from non-user-backed
iterators (eg. KVEC). With these changes, cifs will apply the
appropriate cleanup.
- Making it easier to transition to using folios in cifs rather than
pages by dealing with them through BVEC and XARRAY iterators.
- Allowing cifs to use the new splice function
The remainder are:
- fixes for stable, including various fixes for uninitialized memory,
wrong length field causing mount issue to very old servers,
important directory lease fixes and reconnect fixes
- cleanups (unused code removal, change one element array usage, and
a change form strtobool to kstrtobool, and Kconfig cleanups)
- SMBDIRECT (RDMA) fixes including iov_iter integration and UAF fixes
- reconnect fixes
- multichannel fixes, including improving channel allocation (to
least used channel)
- remove the last use of lock_page_killable by moving to
folio_lock_killable"
* tag '6.3-rc-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6: (46 commits)
update internal module version number for cifs.ko
cifs: update ip_addr for ses only for primary chan setup
cifs: use tcon allocation functions even for dummy tcon
cifs: use the least loaded channel for sending requests
cifs: DIO to/from KVEC-type iterators should now work
cifs: Remove unused code
cifs: Build the RDMA SGE list directly from an iterator
cifs: Change the I/O paths to use an iterator rather than a page list
cifs: Add a function to read into an iter from a socket
cifs: Add some helper functions
cifs: Add a function to Hash the contents of an iterator
cifs: Add a function to build an RDMA SGE list from an iterator
netfs: Add a function to extract an iterator into a scatterlist
netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator
cifs: Implement splice_read to pass down ITER_BVEC not ITER_PIPE
splice: Export filemap/direct_splice_read()
iov_iter: Add a function to extract a page list from an iterator
iov_iter: Define flags to qualify page extraction.
splice: Add a func to do a splice from an O_DIRECT file without ITER_PIPE
splice: Add a func to do a splice from a buffered file without ITER_PIPE
...
filemap_splice_read() and direct_splice_read() should be exported.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Steve French <sfrench@samba.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-cifs@vger.kernel.org
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Signed-off-by: Steve French <stfrench@microsoft.com>
Implement a function, direct_file_splice(), that deals with this by using
an ITER_BVEC iterator instead of an ITER_PIPE iterator as the former won't
free its buffers when reverted. The function bulk allocates all the
buffers it thinks it is going to use in advance, does the read
synchronously and only then trims the buffer down. The pages we did use
get pushed into the pipe.
This fixes a problem with the upcoming iov_iter_extract_pages() function,
whereby pages extracted from a non-user-backed iterator such as ITER_PIPE
aren't pinned. __iomap_dio_rw(), however, calls iov_iter_revert() to
shorten the iterator to just the bufferage it is going to use - which has
the side-effect of freeing the excess pipe buffers, even though they're
attached to a bio and may get written to by DMA (thanks to Hillf Danton for
spotting this[1]).
This then causes memory corruption that is particularly noticeable when the
syzbot test[2] is run. The test boils down to:
out = creat(argv[1], 0666);
ftruncate(out, 0x800);
lseek(out, 0x200, SEEK_SET);
in = open(argv[1], O_RDONLY | O_DIRECT | O_NOFOLLOW);
sendfile(out, in, NULL, 0x1dd00);
run repeatedly in parallel. What I think is happening is that ftruncate()
occasionally shortens the DIO read that's about to be made by sendfile's
splice core by reducing i_size.
This should be more efficient for DIO read by virtue of doing a bulk page
allocation, but slightly less efficient by ignoring any partial page in the
pipe.
Reported-by: syzbot+a440341a59e3b7142895@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
Link: https://lore.kernel.org/r/20230207094731.1390-1-hdanton@sina.com/ [1]
Link: https://lore.kernel.org/r/000000000000b0b3c005f3a09383@google.com/ [2]
Signed-off-by: Steve French <stfrench@microsoft.com>
READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.
Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
... and untangle the cleanup on failure to add into pipe.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use pipe_discard_from() explicitly in generic_file_read_iter(); don't bother
with rather non-obvious use of iov_iter_advance() in there.
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The original direct splicing mechanism from Jens required the input to
be a regular file because it was avoiding the special socket case. It
also recognized blkdevs as being close enough to a regular file. But it
forgot about chardevs, which behave the same way and work fine here.
This is an okayish heuristic, but it doesn't totally work. For example,
a few chardevs should be spliceable here. And a few regular files
shouldn't. This patch fixes this by instead checking whether FMODE_LSEEK
is set, which represents decently enough what we need rewinding for when
splicing to internal pipes.
Fixes: b92ce55893 ("[PATCH] splice: add direct fd <-> fd splicing support")
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Add kernel-doc and return the number of pages removed in order to
get the statistics right in __invalidate_mapping_pages().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
This saves a lot of calls to compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
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Merge tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block
Pull core block updates from Jens Axboe:
"Another nice round of removing more code than what is added, mostly
due to Christoph's relentless pursuit of tech debt removal/cleanups.
This pull request contains:
- Two series of BFQ improvements (Paolo, Jan, Jia)
- Block iov_iter improvements (Pavel)
- bsg error path fix (Pan)
- blk-mq scheduler improvements (Jan)
- -EBUSY discard fix (Jan)
- bvec allocation improvements (Ming, Christoph)
- bio allocation and init improvements (Christoph)
- Store bdev pointer in bio instead of gendisk + partno (Christoph)
- Block trace point cleanups (Christoph)
- hard read-only vs read-only split (Christoph)
- Block based swap cleanups (Christoph)
- Zoned write granularity support (Damien)
- Various fixes/tweaks (Chunguang, Guoqing, Lei, Lukas, Huhai)"
* tag 'for-5.12/block-2021-02-17' of git://git.kernel.dk/linux-block: (104 commits)
mm: simplify swapdev_block
sd_zbc: clear zone resources for non-zoned case
block: introduce blk_queue_clear_zone_settings()
zonefs: use zone write granularity as block size
block: introduce zone_write_granularity limit
block: use blk_queue_set_zoned in add_partition()
nullb: use blk_queue_set_zoned() to setup zoned devices
nvme: cleanup zone information initialization
block: document zone_append_max_bytes attribute
block: use bi_max_vecs to find the bvec pool
md/raid10: remove dead code in reshape_request
block: mark the bio as cloned in bio_iov_bvec_set
block: set BIO_NO_PAGE_REF in bio_iov_bvec_set
block: remove a layer of indentation in bio_iov_iter_get_pages
block: turn the nr_iovecs argument to bio_alloc* into an unsigned short
block: remove the 1 and 4 vec bvec_slabs entries
block: streamline bvec_alloc
block: factor out a bvec_alloc_gfp helper
block: move struct biovec_slab to bio.c
block: reuse BIO_INLINE_VECS for integrity bvecs
...
Both callers have the identical logics limiting the amount of
data we try to read into pipe - no more than would fit into
that pipe. Move that into do_splice_to() itself.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
iter_file_splice_write() may spawn bvec segments with zero-length. In
preparation for prohibiting them, filter out by hand at splice level.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Merge tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
- fsize was missed in previous unification of work flags
- Few fixes cleaning up the flags unification creds cases (Pavel)
- Fix NUMA affinities for completely unplugged/replugged node for io-wq
- Two fallout fixes from the set_fs changes. One local to io_uring, one
for the splice entry point that io_uring uses.
- Linked timeout fixes (Pavel)
- Removal of ->flush() ->files work-around that we don't need anymore
with referenced files (Pavel)
- Various cleanups (Pavel)
* tag 'io_uring-5.10-2020-10-24' of git://git.kernel.dk/linux-block:
splice: change exported internal do_splice() helper to take kernel offset
io_uring: make loop_rw_iter() use original user supplied pointers
io_uring: remove req cancel in ->flush()
io-wq: re-set NUMA node affinities if CPUs come online
io_uring: don't reuse linked_timeout
io_uring: unify fsize with def->work_flags
io_uring: fix racy REQ_F_LINK_TIMEOUT clearing
io_uring: do poll's hash_node init in common code
io_uring: inline io_poll_task_handler()
io_uring: remove extra ->file check in poll prep
io_uring: make cached_cq_overflow non atomic_t
io_uring: inline io_fail_links()
io_uring: kill ref get/drop in personality init
io_uring: flags-based creds init in queue
With the set_fs change, we can no longer rely on copy_{to,from}_user()
accepting a kernel pointer, and it was bad form to do so anyway. Clean
this up and change the internal helper that io_uring uses to deal with
kernel pointers instead. This puts the offset copy in/out in __do_splice()
instead, which just calls the same helper.
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Pull initial set_fs() removal from Al Viro:
"Christoph's set_fs base series + fixups"
* 'work.set_fs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
fs: Allow a NULL pos pointer to __kernel_read
fs: Allow a NULL pos pointer to __kernel_write
powerpc: remove address space overrides using set_fs()
powerpc: use non-set_fs based maccess routines
x86: remove address space overrides using set_fs()
x86: make TASK_SIZE_MAX usable from assembly code
x86: move PAGE_OFFSET, TASK_SIZE & friends to page_{32,64}_types.h
lkdtm: remove set_fs-based tests
test_bitmap: remove user bitmap tests
uaccess: add infrastructure for kernel builds with set_fs()
fs: don't allow splice read/write without explicit ops
fs: don't allow kernel reads and writes without iter ops
sysctl: Convert to iter interfaces
proc: add a read_iter method to proc proc_ops
proc: cleanup the compat vs no compat file ops
proc: remove a level of indentation in proc_get_inode
Pull compat iovec cleanups from Al Viro:
"Christoph's series around import_iovec() and compat variant thereof"
* 'work.iov_iter' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
security/keys: remove compat_keyctl_instantiate_key_iov
mm: remove compat_process_vm_{readv,writev}
fs: remove compat_sys_vmsplice
fs: remove the compat readv/writev syscalls
fs: remove various compat readv/writev helpers
iov_iter: transparently handle compat iovecs in import_iovec
iov_iter: refactor rw_copy_check_uvector and import_iovec
iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c
compat.h: fix a spelling error in <linux/compat.h>
Tetsuo Handa reports that splice() can return 0 before the real EOF, if
the data in the splice source pipe is an empty pipe buffer. That empty
pipe buffer case doesn't happen in any normal situation, but you can
trigger it by doing a write to a pipe that fails due to a page fault.
Tetsuo has a test-case to show the behavior:
#define _GNU_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, char *argv[])
{
const int fd = open("/tmp/testfile", O_WRONLY | O_CREAT, 0600);
int pipe_fd[2] = { -1, -1 };
pipe(pipe_fd);
write(pipe_fd[1], NULL, 4096);
/* This splice() should wait unless interrupted. */
return !splice(pipe_fd[0], NULL, fd, NULL, 65536, 0);
}
which results in
write(5, NULL, 4096) = -1 EFAULT (Bad address)
splice(4, NULL, 3, NULL, 65536, 0) = 0
and this can confuse splice() users into believing they have hit EOF
prematurely.
The issue was introduced when the pipe write code started pre-allocating
the pipe buffers before copying data from user space.
This is modified verion of Tetsuo's original patch.
Fixes: a194dfe6e6 ("pipe: Rearrange sequence in pipe_write() to preallocate slot")
Link:https://lore.kernel.org/linux-fsdevel/20201005121339.4063-1-penguin-kernel@I-love.SAKURA.ne.jp/
Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Acked-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Now that import_iovec handles compat iovecs, the native vmsplice syscall
can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use in compat_syscall to import either native or the compat iovecs, and
remove the now superflous compat_import_iovec.
This removes the need for special compat logic in most callers, and
the remaining ones can still be simplified by using __import_iovec
with a bool compat parameter.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The pipe splice code still used the old model of waiting for pipe IO by
using a non-specific "pipe_wait()" that waited for any pipe event to
happen, which depended on all pipe IO being entirely serialized by the
pipe lock. So by checking the state you were waiting for, and then
adding yourself to the wait queue before dropping the lock, you were
guaranteed to see all the wakeups.
Strictly speaking, the actual wakeups were not done under the lock, but
the pipe_wait() model still worked, because since the waiter held the
lock when checking whether it should sleep, it would always see the
current state, and the wakeup was always done after updating the state.
However, commit 0ddad21d3e ("pipe: use exclusive waits when reading or
writing") split the single wait-queue into two, and in the process also
made the "wait for event" code wait for _two_ wait queues, and that then
showed a race with the wakers that were not serialized by the pipe lock.
It's only splice that used that "pipe_wait()" model, so the problem
wasn't obvious, but Josef Bacik reports:
"I hit a hang with fstest btrfs/187, which does a btrfs send into
/dev/null. This works by creating a pipe, the write side is given to
the kernel to write into, and the read side is handed to a thread that
splices into a file, in this case /dev/null.
The box that was hung had the write side stuck here [pipe_write] and
the read side stuck here [splice_from_pipe_next -> pipe_wait].
[ more details about pipe_wait() scenario ]
The problem is we're doing the prepare_to_wait, which sets our state
each time, however we can be woken up either with reads or writes. In
the case above we race with the WRITER waking us up, and re-set our
state to INTERRUPTIBLE, and thus never break out of schedule"
Josef had a patch that avoided the issue in pipe_wait() by just making
it set the state only once, but the deeper problem is that pipe_wait()
depends on a level of synchonization by the pipe mutex that it really
shouldn't. And the whole "wait for any pipe state change" model really
isn't very good to begin with.
So rather than trying to work around things in pipe_wait(), remove that
legacy model of "wait for arbitrary pipe event" entirely, and actually
create functions that wait for the pipe actually being readable or
writable, and can do so without depending on the pipe lock serializing
everything.
Fixes: 0ddad21d3e ("pipe: use exclusive waits when reading or writing")
Link: https://lore.kernel.org/linux-fsdevel/bfa88b5ad6f069b2b679316b9e495a970130416c.1601567868.git.josef@toxicpanda.com/
Reported-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-and-tested-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
default_file_splice_write is the last piece of generic code that uses
set_fs to make the uaccess routines operate on kernel pointers. It
implements a "fallback loop" for splicing from files that do not actually
provide a proper splice_read method. The usual file systems and other
high bandwidth instances all provide a ->splice_read, so this just removes
support for various device drivers and procfs/debugfs files. If splice
support for any of those turns out to be important it can be added back
by switching them to the iter ops and using generic_file_splice_read.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Merge tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs
Pull notification queue from David Howells:
"This adds a general notification queue concept and adds an event
source for keys/keyrings, such as linking and unlinking keys and
changing their attributes.
Thanks to Debarshi Ray, we do have a pull request to use this to fix a
problem with gnome-online-accounts - as mentioned last time:
https://gitlab.gnome.org/GNOME/gnome-online-accounts/merge_requests/47
Without this, g-o-a has to constantly poll a keyring-based kerberos
cache to find out if kinit has changed anything.
[ There are other notification pending: mount/sb fsinfo notifications
for libmount that Karel Zak and Ian Kent have been working on, and
Christian Brauner would like to use them in lxc, but let's see how
this one works first ]
LSM hooks are included:
- A set of hooks are provided that allow an LSM to rule on whether or
not a watch may be set. Each of these hooks takes a different
"watched object" parameter, so they're not really shareable. The
LSM should use current's credentials. [Wanted by SELinux & Smack]
- A hook is provided to allow an LSM to rule on whether or not a
particular message may be posted to a particular queue. This is
given the credentials from the event generator (which may be the
system) and the watch setter. [Wanted by Smack]
I've provided SELinux and Smack with implementations of some of these
hooks.
WHY
===
Key/keyring notifications are desirable because if you have your
kerberos tickets in a file/directory, your Gnome desktop will monitor
that using something like fanotify and tell you if your credentials
cache changes.
However, we also have the ability to cache your kerberos tickets in
the session, user or persistent keyring so that it isn't left around
on disk across a reboot or logout. Keyrings, however, cannot currently
be monitored asynchronously, so the desktop has to poll for it - not
so good on a laptop. This facility will allow the desktop to avoid the
need to poll.
DESIGN DECISIONS
================
- The notification queue is built on top of a standard pipe. Messages
are effectively spliced in. The pipe is opened with a special flag:
pipe2(fds, O_NOTIFICATION_PIPE);
The special flag has the same value as O_EXCL (which doesn't seem
like it will ever be applicable in this context)[?]. It is given up
front to make it a lot easier to prohibit splice&co from accessing
the pipe.
[?] Should this be done some other way? I'd rather not use up a new
O_* flag if I can avoid it - should I add a pipe3() system call
instead?
The pipe is then configured::
ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, queue_depth);
ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
Messages are then read out of the pipe using read().
- It should be possible to allow write() to insert data into the
notification pipes too, but this is currently disabled as the
kernel has to be able to insert messages into the pipe *without*
holding pipe->mutex and the code to make this work needs careful
auditing.
- sendfile(), splice() and vmsplice() are disabled on notification
pipes because of the pipe->mutex issue and also because they
sometimes want to revert what they just did - but one or more
notification messages might've been interleaved in the ring.
- The kernel inserts messages with the wait queue spinlock held. This
means that pipe_read() and pipe_write() have to take the spinlock
to update the queue pointers.
- Records in the buffer are binary, typed and have a length so that
they can be of varying size.
This allows multiple heterogeneous sources to share a common
buffer; there are 16 million types available, of which I've used
just a few, so there is scope for others to be used. Tags may be
specified when a watchpoint is created to help distinguish the
sources.
- Records are filterable as types have up to 256 subtypes that can be
individually filtered. Other filtration is also available.
- Notification pipes don't interfere with each other; each may be
bound to a different set of watches. Any particular notification
will be copied to all the queues that are currently watching for it
- and only those that are watching for it.
- When recording a notification, the kernel will not sleep, but will
rather mark a queue as having lost a message if there's
insufficient space. read() will fabricate a loss notification
message at an appropriate point later.
- The notification pipe is created and then watchpoints are attached
to it, using one of:
keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);
watch_mount(AT_FDCWD, "/", 0, fd, 0x02);
watch_sb(AT_FDCWD, "/mnt", 0, fd, 0x03);
where in both cases, fd indicates the queue and the number after is
a tag between 0 and 255.
- Watches are removed if either the notification pipe is destroyed or
the watched object is destroyed. In the latter case, a message will
be generated indicating the enforced watch removal.
Things I want to avoid:
- Introducing features that make the core VFS dependent on the
network stack or networking namespaces (ie. usage of netlink).
- Dumping all this stuff into dmesg and having a daemon that sits
there parsing the output and distributing it as this then puts the
responsibility for security into userspace and makes handling
namespaces tricky. Further, dmesg might not exist or might be
inaccessible inside a container.
- Letting users see events they shouldn't be able to see.
TESTING AND MANPAGES
====================
- The keyutils tree has a pipe-watch branch that has keyctl commands
for making use of notifications. Proposed manual pages can also be
found on this branch, though a couple of them really need to go to
the main manpages repository instead.
If the kernel supports the watching of keys, then running "make
test" on that branch will cause the testing infrastructure to spawn
a monitoring process on the side that monitors a notifications pipe
for all the key/keyring changes induced by the tests and they'll
all be checked off to make sure they happened.
https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/keyutils.git/log/?h=pipe-watch
- A test program is provided (samples/watch_queue/watch_test) that
can be used to monitor for keyrings, mount and superblock events.
Information on the notifications is simply logged to stdout"
* tag 'notifications-20200601' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
smack: Implement the watch_key and post_notification hooks
selinux: Implement the watch_key security hook
keys: Make the KEY_NEED_* perms an enum rather than a mask
pipe: Add notification lossage handling
pipe: Allow buffers to be marked read-whole-or-error for notifications
Add sample notification program
watch_queue: Add a key/keyring notification facility
security: Add hooks to rule on setting a watch
pipe: Add general notification queue support
pipe: Add O_NOTIFICATION_PIPE
security: Add a hook for the point of notification insertion
uapi: General notification queue definitions
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Merge tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block
Pull io_uring updates from Jens Axboe:
"A relatively quiet round, mostly just fixes and code improvements. In
particular:
- Make statx just use the generic statx handler, instead of open
coding it. We don't need that anymore, as we always call it async
safe (Bijan)
- Enable closing of the ring itself. Also fixes O_PATH closure (me)
- Properly name completion members (me)
- Batch reap of dead file registrations (me)
- Allow IORING_OP_POLL with double waitqueues (me)
- Add tee(2) support (Pavel)
- Remove double off read (Pavel)
- Fix overflow cancellations (Pavel)
- Improve CQ timeouts (Pavel)
- Async defer drain fixes (Pavel)
- Add support for enabling/disabling notifications on a registered
eventfd (Stefano)
- Remove dead state parameter (Xiaoguang)
- Disable SQPOLL submit on dying ctx (Xiaoguang)
- Various code cleanups"
* tag 'for-5.8/io_uring-2020-06-01' of git://git.kernel.dk/linux-block: (29 commits)
io_uring: fix overflowed reqs cancellation
io_uring: off timeouts based only on completions
io_uring: move timeouts flushing to a helper
statx: hide interfaces no longer used by io_uring
io_uring: call statx directly
statx: allow system call to be invoked from io_uring
io_uring: add io_statx structure
io_uring: get rid of manual punting in io_close
io_uring: separate DRAIN flushing into a cold path
io_uring: don't re-read sqe->off in timeout_prep()
io_uring: simplify io_timeout locking
io_uring: fix flush req->refs underflow
io_uring: don't submit sqes when ctx->refs is dying
io_uring: async task poll trigger cleanup
io_uring: add tee(2) support
splice: export do_tee()
io_uring: don't repeat valid flag list
io_uring: rename io_file_put()
io_uring: remove req->needs_fixed_files
io_uring: cleanup io_poll_remove_one() logic
...
And replace the arcane return value convention with a simple bool
where true means success and false means failure.
[AV: braino fix folded in]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
