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2019-05-21treewide: Add SPDX license identifier - Makefile/KconfigThomas Gleixner1-0/+1
Add SPDX license identifiers to all Make/Kconfig files which: - Have no license information of any form These files fall under the project license, GPL v2 only. The resulting SPDX license identifier is: GPL-2.0-only Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-18treewide: prefix header search paths with $(srctree)/Masahiro Yamada1-1/+1
Currently, the Kbuild core manipulates header search paths in a crazy way [1]. To fix this mess, I want all Makefiles to add explicit $(srctree)/ to the search paths in the srctree. Some Makefiles are already written in that way, but not all. The goal of this work is to make the notation consistent, and finally get rid of the gross hacks. Having whitespaces after -I does not matter since commit 48f6e3cf5bc6 ("kbuild: do not drop -I without parameter"). [1]: https://patchwork.kernel.org/patch/9632347/ Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-23bpfilter: re-add header search paths to tools include to fix build errorMasahiro Yamada1-0/+1
I thought header search paths to tools/include(/uapi) were unneeded, but it looks like a build error occurs depending on the compiler. Commit 303a339f30a9 ("bpfilter: remove extra header search paths for bpfilter_umh") reintroduced the build error fixed by commit ae40832e53c3 ("bpfilter: fix a build err"). Apology for the breakage, and thanks to Guenter for reporting this. Fixes: 303a339f30a9 ("bpfilter: remove extra header search paths for bpfilter_umh") Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-02-03bpfilter: remove extra header search paths for bpfilter_umhMasahiro Yamada2-2/+1
Currently, the header search paths -Itools/include and -Itools/include/uapi are not used. Let's drop the unused code. We can remove -I. too by fixing up one C file. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-16net: bpfilter: change section name of bpfilter UMH blob.Taehee Yoo1-1/+1
The section of bpfilter UMH blob is the ".bpfilter_umh". but this is not an explicit section. so linking warning occurred at compile time for the powerpc. So, this patch makes use of the ".rodata" instead of the ".bpfilter_umh". Config condition: CONFIG_BPFILTER=y CONFIG_BPFILTER_UMH=y Result: ld: warning: orphan section `.bpfilter_umh' from `net/bpfilter/bpfilter_umh_blob.o' being placed in section `.bpfilter_umh' Fixes: 61fbf5933d42 ("net: bpfilter: restart bpfilter_umh when error occurred") Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-11net: bpfilter: disallow to remove bpfilter module while being usedTaehee Yoo1-17/+11
The bpfilter.ko module can be removed while functions of the bpfilter.ko are executing. so panic can occurred. in order to protect that, locks can be used. a bpfilter_lock protects routines in the __bpfilter_process_sockopt() but it's not enough because __exit routine can be executed concurrently. Now, the bpfilter_umh can not run in parallel. So, the module do not removed while it's being used and it do not double-create UMH process. The members of the umh_info and the bpfilter_umh_ops are protected by the bpfilter_umh_ops.lock. test commands: while : do iptables -I FORWARD -m string --string ap --algo kmp & modprobe -rv bpfilter & done splat looks like: [ 298.623435] BUG: unable to handle kernel paging request at fffffbfff807440b [ 298.628512] #PF error: [normal kernel read fault] [ 298.633018] PGD 124327067 P4D 124327067 PUD 11c1a3067 PMD 119eb2067 PTE 0 [ 298.638859] Oops: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN PTI [ 298.638859] CPU: 0 PID: 2997 Comm: iptables Not tainted 4.20.0+ #154 [ 298.638859] RIP: 0010:__mutex_lock+0x6b9/0x16a0 [ 298.638859] Code: c0 00 00 e8 89 82 ff ff 80 bd 8f fc ff ff 00 0f 85 d9 05 00 00 48 8b 85 80 fc ff ff 48 bf 00 00 00 00 00 fc ff df 48 c1 e8 03 <80> 3c 38 00 0f 85 1d 0e 00 00 48 8b 85 c8 fc ff ff 49 39 47 58 c6 [ 298.638859] RSP: 0018:ffff88810e7777a0 EFLAGS: 00010202 [ 298.638859] RAX: 1ffffffff807440b RBX: ffff888111bd4d80 RCX: 0000000000000000 [ 298.638859] RDX: 1ffff110235ff806 RSI: ffff888111bd5538 RDI: dffffc0000000000 [ 298.638859] RBP: ffff88810e777b30 R08: 0000000080000002 R09: 0000000000000000 [ 298.638859] R10: 0000000000000000 R11: 0000000000000000 R12: fffffbfff168a42c [ 298.638859] R13: ffff888111bd4d80 R14: ffff8881040e9a05 R15: ffffffffc03a2000 [ 298.638859] FS: 00007f39e3758700(0000) GS:ffff88811ae00000(0000) knlGS:0000000000000000 [ 298.638859] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 298.638859] CR2: fffffbfff807440b CR3: 000000011243e000 CR4: 00000000001006f0 [ 298.638859] Call Trace: [ 298.638859] ? mutex_lock_io_nested+0x1560/0x1560 [ 298.638859] ? kasan_kmalloc+0xa0/0xd0 [ 298.638859] ? kmem_cache_alloc+0x1c2/0x260 [ 298.638859] ? __alloc_file+0x92/0x3c0 [ 298.638859] ? alloc_empty_file+0x43/0x120 [ 298.638859] ? alloc_file_pseudo+0x220/0x330 [ 298.638859] ? sock_alloc_file+0x39/0x160 [ 298.638859] ? __sys_socket+0x113/0x1d0 [ 298.638859] ? __x64_sys_socket+0x6f/0xb0 [ 298.638859] ? do_syscall_64+0x138/0x560 [ 298.638859] ? entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 298.638859] ? __alloc_file+0x92/0x3c0 [ 298.638859] ? init_object+0x6b/0x80 [ 298.638859] ? cyc2ns_read_end+0x10/0x10 [ 298.638859] ? cyc2ns_read_end+0x10/0x10 [ 298.638859] ? hlock_class+0x140/0x140 [ 298.638859] ? sched_clock_local+0xd4/0x140 [ 298.638859] ? sched_clock_local+0xd4/0x140 [ 298.638859] ? check_flags.part.37+0x440/0x440 [ 298.638859] ? __lock_acquire+0x4f90/0x4f90 [ 298.638859] ? set_rq_offline.part.89+0x140/0x140 [ ... ] Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-11net: bpfilter: restart bpfilter_umh when error occurredTaehee Yoo2-11/+28
The bpfilter_umh will be stopped via __stop_umh() when the bpfilter error occurred. The bpfilter_umh() couldn't start again because there is no restart routine. The section of the bpfilter_umh_{start/end} is no longer .init.rodata because these area should be reused in the restart routine. hence the section name is changed to .bpfilter_umh. The bpfilter_ops->start() is restart callback. it will be called when bpfilter_umh is stopped. The stop bit means bpfilter_umh is stopped. this bit is set by both start and stop routine. Before this patch, Test commands: $ iptables -vnL $ kill -9 <pid of bpfilter_umh> $ iptables -vnL [ 480.045136] bpfilter: write fail -32 $ iptables -vnL All iptables commands will fail. After this patch, Test commands: $ iptables -vnL $ kill -9 <pid of bpfilter_umh> $ iptables -vnL $ iptables -vnL Now, all iptables commands will work. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-11net: bpfilter: use cleanup callback to release umh_infoTaehee Yoo1-13/+10
Now, UMH process is killed, do_exit() calls the umh_info->cleanup callback to release members of the umh_info. This patch makes bpfilter_umh's cleanup routine to use the umh_info->cleanup callback. Signed-off-by: Taehee Yoo <ap420073@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-22net: bpfilter: Set user mode helper's command lineOlivier Brunel1-0/+1
Signed-off-by: Olivier Brunel <jjk@jjacky.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-17net: bpfilter: use get_pid_task instead of pid_taskTaehee Yoo1-2/+4
pid_task() dereferences rcu protected tasks array. But there is no rcu_read_lock() in shutdown_umh() routine so that rcu_read_lock() is needed. get_pid_task() is wrapper function of pid_task. it holds rcu_read_lock() then calls pid_task(). if task isn't NULL, it increases reference count of task. test commands: %modprobe bpfilter %modprobe -rv bpfilter splat looks like: [15102.030932] ============================= [15102.030957] WARNING: suspicious RCU usage [15102.030985] 4.19.0-rc7+ #21 Not tainted [15102.031010] ----------------------------- [15102.031038] kernel/pid.c:330 suspicious rcu_dereference_check() usage! [15102.031063] other info that might help us debug this: [15102.031332] rcu_scheduler_active = 2, debug_locks = 1 [15102.031363] 1 lock held by modprobe/1570: [15102.031389] #0: 00000000580ef2b0 (bpfilter_lock){+.+.}, at: stop_umh+0x13/0x52 [bpfilter] [15102.031552] stack backtrace: [15102.031583] CPU: 1 PID: 1570 Comm: modprobe Not tainted 4.19.0-rc7+ #21 [15102.031607] Hardware name: To be filled by O.E.M. To be filled by O.E.M./Aptio CRB, BIOS 5.6.5 07/08/2015 [15102.031628] Call Trace: [15102.031676] dump_stack+0xc9/0x16b [15102.031723] ? show_regs_print_info+0x5/0x5 [15102.031801] ? lockdep_rcu_suspicious+0x117/0x160 [15102.031855] pid_task+0x134/0x160 [15102.031900] ? find_vpid+0xf0/0xf0 [15102.032017] shutdown_umh.constprop.1+0x1e/0x53 [bpfilter] [15102.032055] stop_umh+0x46/0x52 [bpfilter] [15102.032092] __x64_sys_delete_module+0x47e/0x570 [ ... ] Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Taehee Yoo <ap420073@gmail.com> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-10-05net: bpfilter: Fix type cast and pointer warningsShanthosh RK1-2/+2
Fixes the following Sparse warnings: net/bpfilter/bpfilter_kern.c:62:21: warning: cast removes address space of expression net/bpfilter/bpfilter_kern.c:101:49: warning: Using plain integer as NULL pointer Signed-off-by: Shanthosh RK <shanthosh.rk@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-08-15Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-nextLinus Torvalds1-1/+0
Pull networking updates from David Miller: "Highlights: - Gustavo A. R. Silva keeps working on the implicit switch fallthru changes. - Support 802.11ax High-Efficiency wireless in cfg80211 et al, From Luca Coelho. - Re-enable ASPM in r8169, from Kai-Heng Feng. - Add virtual XFRM interfaces, which avoids all of the limitations of existing IPSEC tunnels. From Steffen Klassert. - Convert GRO over to use a hash table, so that when we have many flows active we don't traverse a long list during accumluation. - Many new self tests for routing, TC, tunnels, etc. Too many contributors to mention them all, but I'm really happy to keep seeing this stuff. - Hardware timestamping support for dpaa_eth/fsl-fman from Yangbo Lu. - Lots of cleanups and fixes in L2TP code from Guillaume Nault. - Add IPSEC offload support to netdevsim, from Shannon Nelson. - Add support for slotting with non-uniform distribution to netem packet scheduler, from Yousuk Seung. - Add UDP GSO support to mlx5e, from Boris Pismenny. - Support offloading of Team LAG in NFP, from John Hurley. - Allow to configure TX queue selection based upon RX queue, from Amritha Nambiar. - Support ethtool ring size configuration in aquantia, from Anton Mikaev. - Support DSCP and flowlabel per-transport in SCTP, from Xin Long. - Support list based batching and stack traversal of SKBs, this is very exciting work. From Edward Cree. - Busyloop optimizations in vhost_net, from Toshiaki Makita. - Introduce the ETF qdisc, which allows time based transmissions. IGB can offload this in hardware. From Vinicius Costa Gomes. - Add parameter support to devlink, from Moshe Shemesh. - Several multiplication and division optimizations for BPF JIT in nfp driver, from Jiong Wang. - Lots of prepatory work to make more of the packet scheduler layer lockless, when possible, from Vlad Buslov. - Add ACK filter and NAT awareness to sch_cake packet scheduler, from Toke Høiland-Jørgensen. - Support regions and region snapshots in devlink, from Alex Vesker. - Allow to attach XDP programs to both HW and SW at the same time on a given device, with initial support in nfp. From Jakub Kicinski. - Add TLS RX offload and support in mlx5, from Ilya Lesokhin. - Use PHYLIB in r8169 driver, from Heiner Kallweit. - All sorts of changes to support Spectrum 2 in mlxsw driver, from Ido Schimmel. - PTP support in mv88e6xxx DSA driver, from Andrew Lunn. - Make TCP_USER_TIMEOUT socket option more accurate, from Jon Maxwell. - Support for templates in packet scheduler classifier, from Jiri Pirko. - IPV6 support in RDS, from Ka-Cheong Poon. - Native tproxy support in nf_tables, from Máté Eckl. - Maintain IP fragment queue in an rbtree, but optimize properly for in-order frags. From Peter Oskolkov. - Improvde handling of ACKs on hole repairs, from Yuchung Cheng" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1996 commits) bpf: test: fix spelling mistake "REUSEEPORT" -> "REUSEPORT" hv/netvsc: Fix NULL dereference at single queue mode fallback net: filter: mark expected switch fall-through xen-netfront: fix warn message as irq device name has '/' cxgb4: Add new T5 PCI device ids 0x50af and 0x50b0 net: dsa: mv88e6xxx: missing unlock on error path rds: fix building with IPV6=m inet/connection_sock: prefer _THIS_IP_ to current_text_addr net: dsa: mv88e6xxx: bitwise vs logical bug net: sock_diag: Fix spectre v1 gadget in __sock_diag_cmd() ieee802154: hwsim: using right kind of iteration net: hns3: Add vlan filter setting by ethtool command -K net: hns3: Set tx ring' tc info when netdev is up net: hns3: Remove tx ring BD len register in hns3_enet net: hns3: Fix desc num set to default when setting channel net: hns3: Fix for phy link issue when using marvell phy driver net: hns3: Fix for information of phydev lost problem when down/up net: hns3: Fix for command format parsing error in hclge_is_all_function_id_zero net: hns3: Add support for serdes loopback selftest bnxt_en: take coredump_record structure off stack ...
2018-07-24bpfilter: remove trailing newlineStephen Hemminger1-1/+0
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-07-18kbuild: Rename HOSTLDFLAGS to KBUILD_HOSTLDFLAGSLaura Abbott1-1/+1
In preparation for enabling command line LDFLAGS, re-name HOSTLDFLAGS to KBUILD_HOSTLDFLAGS as the internal use only flags. This should not have any visible effects. Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-18kbuild: Rename HOSTCFLAGS to KBUILD_HOSTCFLAGSLaura Abbott1-1/+1
In preparation for enabling command line CFLAGS, re-name HOSTCFLAGS to KBUILD_HOSTCFLAGS as the internal use only flags. This should not have any visible effects. Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-06-28bpfilter: include bpfilter_umh in assembly instead of using objcopyMasahiro Yamada3-21/+14
What we want here is to embed a user-space program into the kernel. Instead of the complex ELF magic, let's simply wrap it in the assembly with the '.incbin' directive. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-28bpfilter: check compiler capability in KconfigMasahiro Yamada1-1/+1
With the brand-new syntax extension of Kconfig, we can directly check the compiler capability in the configuration phase. If the cc-can-link.sh fails, the BPFILTER_UMH is automatically hidden by the dependency. I also deleted 'default n', which is no-op. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-21bpfilter: fix user mode helper cross compilationMatteo Croce1-1/+1
Use $(OBJDUMP) instead of literal 'objdump' to avoid using host toolchain when cross compiling. Fixes: 421780fd4983 ("bpfilter: fix build error") Signed-off-by: Matteo Croce <mcroce@redhat.com> Reported-by: Stefano Brivio <sbrivio@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-20bpfilter: ignore binary filesMatteo Croce1-0/+1
net/bpfilter/bpfilter_umh is a binary file generated when bpfilter is enabled, add it to .gitignore to avoid committing it. Fixes: d2ba09c17a064 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-20bpfilter: fix build errorMatteo Croce1-2/+4
bpfilter Makefile assumes that the system locale is en_US, and the parsing of objdump output fails. Set LC_ALL=C and, while at it, rewrite the objdump parsing so it spawns only 2 processes instead of 7. Fixes: d2ba09c17a064 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Matteo Croce <mcroce@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-07bpfilter: fix race in pipe accessAlexei Starovoitov1-3/+7
syzbot reported the following crash [ 338.293946] bpfilter: read fail -512 [ 338.304515] kasan: GPF could be caused by NULL-ptr deref or user memory access [ 338.311863] general protection fault: 0000 [#1] SMP KASAN [ 338.344360] RIP: 0010:__vfs_write+0x4a6/0x960 [ 338.426363] Call Trace: [ 338.456967] __kernel_write+0x10c/0x380 [ 338.460928] __bpfilter_process_sockopt+0x1d8/0x35b [ 338.487103] bpfilter_mbox_request+0x4d/0xb0 [ 338.491492] bpfilter_ip_get_sockopt+0x6b/0x90 This can happen when multiple cpus trying to talk to user mode process via bpfilter_mbox_request(). One cpu grabs the mutex while another goes to sleep on the same mutex. Then former cpu sees that umh pipe is down and shuts down the pipes. Later cpu finally acquires the mutex and crashes on freed pipe. Fix the race by using info.pid as an indicator that umh and pipes are healthy and check it after acquiring the mutex. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Reported-by: syzbot+7ade6c94abb2774c0fee@syzkaller.appspotmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-07bpfilter: fix OUTPUT_FORMATAlexei Starovoitov1-1/+1
CONFIG_OUTPUT_FORMAT is x86 only macro. Used objdump to extract elf file format. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Reported-by: David S. Miller <davem@davemloft.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-06-05bpfilter: switch to CC from HOSTCCAlexei Starovoitov1-0/+2
check that CC can build executables and use that compiler instead of HOSTCC Suggested-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-29bpfilter: fix a build errYueHaibing1-1/+1
gcc-7.3.0 report following err: HOSTCC net/bpfilter/main.o In file included from net/bpfilter/main.c:9:0: ./include/uapi/linux/bpf.h:12:10: fatal error: linux/bpf_common.h: No such file or directory #include <linux/bpf_common.h> remove it by adding a include path. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-29bpfilter: fix building without CONFIG_INETArnd Bergmann1-2/+5
bpfilter_process_sockopt is a callback that gets called from ip_setsockopt() and ip_getsockopt(). However, when CONFIG_INET is disabled, it never gets called at all, and assigning a function to the callback pointer results in a link failure: net/bpfilter/bpfilter_kern.o: In function `__stop_umh': bpfilter_kern.c:(.text.unlikely+0x3): undefined reference to `bpfilter_process_sockopt' net/bpfilter/bpfilter_kern.o: In function `load_umh': bpfilter_kern.c:(.init.text+0x73): undefined reference to `bpfilter_process_sockopt' Since there is no caller in this configuration, I assume we can simply make the assignment conditional. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-24bpfilter: don't pass O_CREAT when opening console for debugJakub Kicinski1-1/+1
Passing O_CREAT (00000100) to open means we should also pass file mode as the third parameter. Creating /dev/console as a regular file may not be helpful anyway, so simply drop the flag when opening debug_fd. Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-24bpfilter: fix build dependencyAlexei Starovoitov1-1/+1
BPFILTER could have been enabled without INET causing this build error: ERROR: "bpfilter_process_sockopt" [net/bpfilter/bpfilter.ko] undefined! Fixes: d2ba09c17a06 ("net: add skeleton of bpfilter kernel module") Reported-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2018-05-23net: add skeleton of bpfilter kernel moduleAlexei Starovoitov5-0/+237
bpfilter.ko consists of bpfilter_kern.c (normal kernel module code) and user mode helper code that is embedded into bpfilter.ko The steps to build bpfilter.ko are the following: - main.c is compiled by HOSTCC into the bpfilter_umh elf executable file - with quite a bit of objcopy and Makefile magic the bpfilter_umh elf file is converted into bpfilter_umh.o object file with _binary_net_bpfilter_bpfilter_umh_start and _end symbols Example: $ nm ./bld_x64/net/bpfilter/bpfilter_umh.o 0000000000004cf8 T _binary_net_bpfilter_bpfilter_umh_end 0000000000004cf8 A _binary_net_bpfilter_bpfilter_umh_size 0000000000000000 T _binary_net_bpfilter_bpfilter_umh_start - bpfilter_umh.o and bpfilter_kern.o are linked together into bpfilter.ko bpfilter_kern.c is a normal kernel module code that calls the fork_usermode_blob() helper to execute part of its own data as a user mode process. Notice that _binary_net_bpfilter_bpfilter_umh_start - end is placed into .init.rodata section, so it's freed as soon as __init function of bpfilter.ko is finished. As part of __init the bpfilter.ko does first request/reply action via two unix pipe provided by fork_usermode_blob() helper to make sure that umh is healthy. If not it will kill it via pid. Later bpfilter_process_sockopt() will be called from bpfilter hooks in get/setsockopt() to pass iptable commands into umh via bpfilter.ko If admin does 'rmmod bpfilter' the __exit code bpfilter.ko will kill umh as well. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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