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2020-07-21bpf, netns: Fix build without CONFIG_INETJakub Sitnicki
When CONFIG_NET is set but CONFIG_INET isn't, build fails with: ld: kernel/bpf/net_namespace.o: in function `netns_bpf_attach_type_unneed': kernel/bpf/net_namespace.c:32: undefined reference to `bpf_sk_lookup_enabled' ld: kernel/bpf/net_namespace.o: in function `netns_bpf_attach_type_need': kernel/bpf/net_namespace.c:43: undefined reference to `bpf_sk_lookup_enabled' This is because without CONFIG_INET bpf_sk_lookup_enabled symbol is not available. Wrap references to bpf_sk_lookup_enabled with preprocessor conditionals. Fixes: 1559b4aa1db4 ("inet: Run SK_LOOKUP BPF program on socket lookup") Reported-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested Link: https://lore.kernel.org/bpf/20200721100716.720477-1-jakub@cloudflare.com
2020-07-17inet: Run SK_LOOKUP BPF program on socket lookupJakub Sitnicki
Run a BPF program before looking up a listening socket on the receive path. Program selects a listening socket to yield as result of socket lookup by calling bpf_sk_assign() helper and returning SK_PASS code. Program can revert its decision by assigning a NULL socket with bpf_sk_assign(). Alternatively, BPF program can also fail the lookup by returning with SK_DROP, or let the lookup continue as usual with SK_PASS on return, when no socket has been selected with bpf_sk_assign(). This lets the user match packets with listening sockets freely at the last possible point on the receive path, where we know that packets are destined for local delivery after undergoing policing, filtering, and routing. With BPF code selecting the socket, directing packets destined to an IP range or to a port range to a single socket becomes possible. In case multiple programs are attached, they are run in series in the order in which they were attached. The end result is determined from return codes of all the programs according to following rules: 1. If any program returned SK_PASS and selected a valid socket, the socket is used as result of socket lookup. 2. If more than one program returned SK_PASS and selected a socket, last selection takes effect. 3. If any program returned SK_DROP, and no program returned SK_PASS and selected a socket, socket lookup fails with -ECONNREFUSED. 4. If all programs returned SK_PASS and none of them selected a socket, socket lookup continues to htable-based lookup. Suggested-by: Marek Majkowski <marek@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200717103536.397595-5-jakub@cloudflare.com
2020-07-17bpf: Introduce SK_LOOKUP program type with a dedicated attach pointJakub Sitnicki
Add a new program type BPF_PROG_TYPE_SK_LOOKUP with a dedicated attach type BPF_SK_LOOKUP. The new program kind is to be invoked by the transport layer when looking up a listening socket for a new connection request for connection oriented protocols, or when looking up an unconnected socket for a packet for connection-less protocols. When called, SK_LOOKUP BPF program can select a socket that will receive the packet. This serves as a mechanism to overcome the limits of what bind() API allows to express. Two use-cases driving this work are: (1) steer packets destined to an IP range, on fixed port to a socket 192.0.2.0/24, port 80 -> NGINX socket (2) steer packets destined to an IP address, on any port to a socket 198.51.100.1, any port -> L7 proxy socket In its run-time context program receives information about the packet that triggered the socket lookup. Namely IP version, L4 protocol identifier, and address 4-tuple. Context can be further extended to include ingress interface identifier. To select a socket BPF program fetches it from a map holding socket references, like SOCKMAP or SOCKHASH, and calls bpf_sk_assign(ctx, sk, ...) helper to record the selection. Transport layer then uses the selected socket as a result of socket lookup. In its basic form, SK_LOOKUP acts as a filter and hence must return either SK_PASS or SK_DROP. If the program returns with SK_PASS, transport should look for a socket to receive the packet, or use the one selected by the program if available, while SK_DROP informs the transport layer that the lookup should fail. This patch only enables the user to attach an SK_LOOKUP program to a network namespace. Subsequent patches hook it up to run on local delivery path in ipv4 and ipv6 stacks. Suggested-by: Marek Majkowski <marek@cloudflare.com> Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200717103536.397595-3-jakub@cloudflare.com
2020-07-17bpf, netns: Handle multiple link attachmentsJakub Sitnicki
Extend the BPF netns link callbacks to rebuild (grow/shrink) or update the prog_array at given position when link gets attached/updated/released. This let's us lift the limit of having just one link attached for the new attach type introduced by subsequent patch. No functional changes intended. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200717103536.397595-2-jakub@cloudflare.com
2020-07-16bpf: cpumap: Implement XDP_REDIRECT for eBPF programs attached to map entriesLorenzo Bianconi
Introduce XDP_REDIRECT support for eBPF programs attached to cpumap entries. This patch has been tested on Marvell ESPRESSObin using a modified version of xdp_redirect_cpu sample in order to attach a XDP program to CPUMAP entries to perform a redirect on the mvneta interface. In particular the following scenario has been tested: rq (cpu0) --> mvneta - XDP_REDIRECT (cpu0) --> CPUMAP - XDP_REDIRECT (cpu1) --> mvneta $./xdp_redirect_cpu -p xdp_cpu_map0 -d eth0 -c 1 -e xdp_redirect \ -f xdp_redirect_kern.o -m tx_port -r eth0 tx: 285.2 Kpps rx: 285.2 Kpps Attaching a simple XDP program on eth0 to perform XDP_TX gives comparable results: tx: 288.4 Kpps rx: 288.4 Kpps Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/2cf8373a731867af302b00c4ff16c122630c4980.1594734381.git.lorenzo@kernel.org
2020-07-16bpf: cpumap: Add the possibility to attach an eBPF program to cpumapLorenzo Bianconi
Introduce the capability to attach an eBPF program to cpumap entries. The idea behind this feature is to add the possibility to define on which CPU run the eBPF program if the underlying hw does not support RSS. Current supported verdicts are XDP_DROP and XDP_PASS. This patch has been tested on Marvell ESPRESSObin using xdp_redirect_cpu sample available in the kernel tree to identify possible performance regressions. Results show there are no observable differences in packet-per-second: $./xdp_redirect_cpu --progname xdp_cpu_map0 --dev eth0 --cpu 1 rx: 354.8 Kpps rx: 356.0 Kpps rx: 356.8 Kpps rx: 356.3 Kpps rx: 356.6 Kpps rx: 356.6 Kpps rx: 356.7 Kpps rx: 355.8 Kpps rx: 356.8 Kpps rx: 356.8 Kpps Co-developed-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/5c9febdf903d810b3415732e5cd98491d7d9067a.1594734381.git.lorenzo@kernel.org
2020-07-16cpumap: Formalize map value as a named structLorenzo Bianconi
As it has been already done for devmap, introduce 'struct bpf_cpumap_val' to formalize the expected values that can be passed in for a CPUMAP. Update cpumap code to use the struct. Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com> Link: https://lore.kernel.org/bpf/754f950674665dae6139c061d28c1d982aaf4170.1594734381.git.lorenzo@kernel.org
2020-07-16cpumap: Use non-locked version __ptr_ring_consume_batchedJesper Dangaard Brouer
Commit 77361825bb01 ("bpf: cpumap use ptr_ring_consume_batched") changed away from using single frame ptr_ring dequeue (__ptr_ring_consume) to consume a batched, but it uses a locked version, which as the comment explain isn't needed. Change to use the non-locked version __ptr_ring_consume_batched. Fixes: 77361825bb01 ("bpf: cpumap use ptr_ring_consume_batched") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/a9c7d06f9a009e282209f0c8c7b2c5d9b9ad60b9.1594734381.git.lorenzo@kernel.org
2020-07-15bpf: Fix NULL pointer dereference in __btf_resolve_helper_id()Peilin Ye
Prevent __btf_resolve_helper_id() from dereferencing `btf_vmlinux` as NULL. This patch fixes the following syzbot bug: https://syzkaller.appspot.com/bug?id=f823224ada908fa5c207902a5a62065e53ca0fcc Reported-by: syzbot+ee09bda7017345f1fbe6@syzkaller.appspotmail.com Signed-off-by: Peilin Ye <yepeilin.cs@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200714180904.277512-1-yepeilin.cs@gmail.com
2020-07-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Alexei Starovoitov says: ==================== pull-request: bpf-next 2020-07-13 The following pull-request contains BPF updates for your *net-next* tree. We've added 36 non-merge commits during the last 7 day(s) which contain a total of 62 files changed, 2242 insertions(+), 468 deletions(-). The main changes are: 1) Avoid trace_printk warning banner by switching bpf_trace_printk to use its own tracing event, from Alan. 2) Better libbpf support on older kernels, from Andrii. 3) Additional AF_XDP stats, from Ciara. 4) build time resolution of BTF IDs, from Jiri. 5) BPF_CGROUP_INET_SOCK_RELEASE hook, from Stanislav. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-13bpf: Use BTF_ID to resolve bpf_ctx_convert structJiri Olsa
This way the ID is resolved during compile time, and we can remove the runtime name search. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200711215329.41165-7-jolsa@kernel.org
2020-07-13bpf: Remove btf_id helpers resolvingJiri Olsa
Now when we moved the helpers btf_id arrays into .BTF_ids section, we can remove the code that resolve those IDs in runtime. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200711215329.41165-6-jolsa@kernel.org
2020-07-13bpf: Resolve BTF IDs in vmlinux imageJiri Olsa
Using BTF_ID_LIST macro to define lists for several helpers using BTF arguments. And running resolve_btfids on vmlinux elf object during linking, so the .BTF_ids section gets the IDs resolved. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200711215329.41165-5-jolsa@kernel.org
2020-07-11Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netDavid S. Miller
All conflicts seemed rather trivial, with some guidance from Saeed Mameed on the tc_ct.c one. Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds
Pull networking fixes from David Miller: 1) Restore previous behavior of CAP_SYS_ADMIN wrt loading networking BPF programs, from Maciej Żenczykowski. 2) Fix dropped broadcasts in mac80211 code, from Seevalamuthu Mariappan. 3) Slay memory leak in nl80211 bss color attribute parsing code, from Luca Coelho. 4) Get route from skb properly in ip_route_use_hint(), from Miaohe Lin. 5) Don't allow anything other than ARPHRD_ETHER in llc code, from Eric Dumazet. 6) xsk code dips too deeply into DMA mapping implementation internals. Add dma_need_sync and use it. From Christoph Hellwig 7) Enforce power-of-2 for BPF ringbuf sizes. From Andrii Nakryiko. 8) Check for disallowed attributes when loading flow dissector BPF programs. From Lorenz Bauer. 9) Correct packet injection to L3 tunnel devices via AF_PACKET, from Jason A. Donenfeld. 10) Don't advertise checksum offload on ipa devices that don't support it. From Alex Elder. 11) Resolve several issues in TCP MD5 signature support. Missing memory barriers, bogus options emitted when using syncookies, and failure to allow md5 key changes in established states. All from Eric Dumazet. 12) Fix interface leak in hsr code, from Taehee Yoo. 13) VF reset fixes in hns3 driver, from Huazhong Tan. 14) Make loopback work again with ipv6 anycast, from David Ahern. 15) Fix TX starvation under high load in fec driver, from Tobias Waldekranz. 16) MLD2 payload lengths not checked properly in bridge multicast code, from Linus Lüssing. 17) Packet scheduler code that wants to find the inner protocol currently only works for one level of VLAN encapsulation. Allow Q-in-Q situations to work properly here, from Toke Høiland-Jørgensen. 18) Fix route leak in l2tp, from Xin Long. 19) Resolve conflict between the sk->sk_user_data usage of bpf reuseport support and various protocols. From Martin KaFai Lau. 20) Fix socket cgroup v2 reference counting in some situations, from Cong Wang. 21) Cure memory leak in mlx5 connection tracking offload support, from Eli Britstein. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (146 commits) mlxsw: pci: Fix use-after-free in case of failed devlink reload mlxsw: spectrum_router: Remove inappropriate usage of WARN_ON() net: macb: fix call to pm_runtime in the suspend/resume functions net: macb: fix macb_suspend() by removing call to netif_carrier_off() net: macb: fix macb_get/set_wol() when moving to phylink net: macb: mark device wake capable when "magic-packet" property present net: macb: fix wakeup test in runtime suspend/resume routines bnxt_en: fix NULL dereference in case SR-IOV configuration fails libbpf: Fix libbpf hashmap on (I)LP32 architectures net/mlx5e: CT: Fix memory leak in cleanup net/mlx5e: Fix port buffers cell size value net/mlx5e: Fix 50G per lane indication net/mlx5e: Fix CPU mapping after function reload to avoid aRFS RX crash net/mlx5e: Fix VXLAN configuration restore after function reload net/mlx5e: Fix usage of rcu-protected pointer net/mxl5e: Verify that rpriv is not NULL net/mlx5: E-Switch, Fix vlan or qos setting in legacy mode net/mlx5: Fix eeprom support for SFP module cgroup: Fix sock_cgroup_data on big-endian. selftests: bpf: Fix detach from sockmap tests ...
2020-07-09Merge tag 'kallsyms_show_value-v5.8-rc5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull kallsyms fix from Kees Cook: "Refactor kallsyms_show_value() users for correct cred. I'm not delighted by the timing of getting these changes to you, but it does fix a handful of kernel address exposures, and no one has screamed yet at the patches. Several users of kallsyms_show_value() were performing checks not during "open". Refactor everything needed to gain proper checks against file->f_cred for modules, kprobes, and bpf" * tag 'kallsyms_show_value-v5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: selftests: kmod: Add module address visibility test bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok() kprobes: Do not expose probe addresses to non-CAP_SYSLOG module: Do not expose section addresses to non-CAP_SYSLOG module: Refactor section attr into bin attribute kallsyms: Refactor kallsyms_show_value() to take cred
2020-07-09bpf: net: Avoid incorrect bpf_sk_reuseport_detach callMartin KaFai Lau
bpf_sk_reuseport_detach is currently called when sk->sk_user_data is not NULL. It is incorrect because sk->sk_user_data may not be managed by the bpf's reuseport_array. It has been reported in [1] that, the bpf_sk_reuseport_detach() which is called from udp_lib_unhash() has corrupted the sk_user_data managed by l2tp. This patch solves it by using another bit (defined as SK_USER_DATA_BPF) of the sk_user_data pointer value. It marks that a sk_user_data is managed/owned by BPF. The patch depends on a PTRMASK introduced in commit f1ff5ce2cd5e ("net, sk_msg: Clear sk_user_data pointer on clone if tagged"). [ Note: sk->sk_user_data is used by bpf's reuseport_array only when a sk is added to the bpf's reuseport_array. i.e. doing setsockopt(SO_REUSEPORT) and having "sk->sk_reuseport == 1" alone will not stop sk->sk_user_data being used by other means. ] [1]: https://lore.kernel.org/netdev/20200706121259.GA20199@katalix.com/ Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY") Reported-by: James Chapman <jchapman@katalix.com> Reported-by: syzbot+9f092552ba9a5efca5df@syzkaller.appspotmail.com Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: James Chapman <jchapman@katalix.com> Acked-by: James Chapman <jchapman@katalix.com> Link: https://lore.kernel.org/bpf/20200709061110.4019316-1-kafai@fb.com
2020-07-09bpf: net: Avoid copying sk_user_data of reuseport_array during sk_cloneMartin KaFai Lau
It makes little sense for copying sk_user_data of reuseport_array during sk_clone_lock(). This patch reuses the SK_USER_DATA_NOCOPY bit introduced in commit f1ff5ce2cd5e ("net, sk_msg: Clear sk_user_data pointer on clone if tagged"). It is used to mark the sk_user_data is not supposed to be copied to its clone. Although the cloned sk's sk_user_data will not be used/freed in bpf_sk_reuseport_detach(), this change can still allow the cloned sk's sk_user_data to be used by some other means. Freeing the reuseport_array's sk_user_data does not require a rcu grace period. Thus, the existing rcu_assign_sk_user_data_nocopy() is not used. Fixes: 5dc4c4b7d4e8 ("bpf: Introduce BPF_MAP_TYPE_REUSEPORT_SOCKARRAY") Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20200709061104.4018798-1-kafai@fb.com
2020-07-08bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok()Kees Cook
When evaluating access control over kallsyms visibility, credentials at open() time need to be used, not the "current" creds (though in BPF's case, this has likely always been the same). Plumb access to associated file->f_cred down through bpf_dump_raw_ok() and its callers now that kallsysm_show_value() has been refactored to take struct cred. Cc: Alexei Starovoitov <ast@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: bpf@vger.kernel.org Cc: stable@vger.kernel.org Fixes: 7105e828c087 ("bpf: allow for correlation of maps and helpers in dump") Signed-off-by: Kees Cook <keescook@chromium.org>
2020-07-08bpf: Add BPF_CGROUP_INET_SOCK_RELEASE hookStanislav Fomichev
Sometimes it's handy to know when the socket gets freed. In particular, we'd like to try to use a smarter allocation of ports for bpf_bind and explore the possibility of limiting the number of SOCK_DGRAM sockets the process can have. Implement BPF_CGROUP_INET_SOCK_RELEASE hook that triggers on inet socket release. It triggers only for userspace sockets (not in-kernel ones) and therefore has the same semantics as the existing BPF_CGROUP_INET_SOCK_CREATE. Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200706230128.4073544-2-sdf@google.com
2020-07-04Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextDavid S. Miller
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-07-04 The following pull-request contains BPF updates for your *net-next* tree. We've added 73 non-merge commits during the last 17 day(s) which contain a total of 106 files changed, 5233 insertions(+), 1283 deletions(-). The main changes are: 1) bpftool ability to show PIDs of processes having open file descriptors for BPF map/program/link/BTF objects, relying on BPF iterator progs to extract this info efficiently, from Andrii Nakryiko. 2) Addition of BPF iterator progs for dumping TCP and UDP sockets to seq_files, from Yonghong Song. 3) Support access to BPF map fields in struct bpf_map from programs through BTF struct access, from Andrey Ignatov. 4) Add a bpf_get_task_stack() helper to be able to dump /proc/*/stack via seq_file from BPF iterator progs, from Song Liu. 5) Make SO_KEEPALIVE and related options available to bpf_setsockopt() helper, from Dmitry Yakunin. 6) Optimize BPF sk_storage selection of its caching index, from Martin KaFai Lau. 7) Removal of redundant synchronize_rcu()s from BPF map destruction which has been a historic leftover, from Alexei Starovoitov. 8) Several improvements to test_progs to make it easier to create a shell loop that invokes each test individually which is useful for some CIs, from Jesper Dangaard Brouer. 9) Fix bpftool prog dump segfault when compiled without skeleton code on older clang versions, from John Fastabend. 10) Bunch of cleanups and minor improvements, from various others. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-02bpf: Fix build without CONFIG_STACKTRACESong Liu
Without CONFIG_STACKTRACE stack_trace_save_tsk() is not defined. Let get_callchain_entry_for_task() to always return NULL in such cases. Fixes: fa28dcb82a38 ("bpf: Introduce helper bpf_get_task_stack()") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200703024537.79971-1-songliubraving@fb.com
2020-07-01bpf: Introduce helper bpf_get_task_stack()Song Liu
Introduce helper bpf_get_task_stack(), which dumps stack trace of given task. This is different to bpf_get_stack(), which gets stack track of current task. One potential use case of bpf_get_task_stack() is to call it from bpf_iter__task and dump all /proc/<pid>/stack to a seq_file. bpf_get_task_stack() uses stack_trace_save_tsk() instead of get_perf_callchain() for kernel stack. The benefit of this choice is that stack_trace_save_tsk() doesn't require changes in arch/. The downside of using stack_trace_save_tsk() is that stack_trace_save_tsk() dumps the stack trace to unsigned long array. For 32-bit systems, we need to translate it to u64 array. Signed-off-by: Song Liu <songliubraving@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200630062846.664389-3-songliubraving@fb.com
2020-07-01bpf: Remove redundant synchronize_rcu.Alexei Starovoitov
bpf_free_used_maps() or close(map_fd) will trigger map_free callback. bpf_free_used_maps() is called after bpf prog is no longer executing: bpf_prog_put->call_rcu->bpf_prog_free->bpf_free_used_maps. Hence there is no need to call synchronize_rcu() to protect map elements. Note that hash_of_maps and array_of_maps update/delete inner maps via sys_bpf() that calls maybe_wait_bpf_programs() and synchronize_rcu(). Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lore.kernel.org/bpf/20200630043343.53195-2-alexei.starovoitov@gmail.com
2020-06-30bpf: Fix an incorrect branch elimination by verifierYonghong Song
Wenbo reported an issue in [1] where a checking of null pointer is evaluated as always false. In this particular case, the program type is tp_btf and the pointer to compare is a PTR_TO_BTF_ID. The current verifier considers PTR_TO_BTF_ID always reprents a non-null pointer, hence all PTR_TO_BTF_ID compares to 0 will be evaluated as always not-equal, which resulted in the branch elimination. For example, struct bpf_fentry_test_t { struct bpf_fentry_test_t *a; }; int BPF_PROG(test7, struct bpf_fentry_test_t *arg) { if (arg == 0) test7_result = 1; return 0; } int BPF_PROG(test8, struct bpf_fentry_test_t *arg) { if (arg->a == 0) test8_result = 1; return 0; } In above bpf programs, both branch arg == 0 and arg->a == 0 are removed. This may not be what developer expected. The bug is introduced by Commit cac616db39c2 ("bpf: Verifier track null pointer branch_taken with JNE and JEQ"), where PTR_TO_BTF_ID is considered to be non-null when evaluting pointer vs. scalar comparison. This may be added considering we have PTR_TO_BTF_ID_OR_NULL in the verifier as well. PTR_TO_BTF_ID_OR_NULL is added to explicitly requires a non-NULL testing in selective cases. The current generic pointer tracing framework in verifier always assigns PTR_TO_BTF_ID so users does not need to check NULL pointer at every pointer level like a->b->c->d. We may not want to assign every PTR_TO_BTF_ID as PTR_TO_BTF_ID_OR_NULL as this will require a null test before pointer dereference which may cause inconvenience for developers. But we could avoid branch elimination to preserve original code intention. This patch simply removed PTR_TO_BTD_ID from reg_type_not_null() in verifier, which prevented the above branches from being eliminated. [1]: https://lore.kernel.org/bpf/79dbb7c0-449d-83eb-5f4f-7af0cc269168@fb.com/T/ Fixes: cac616db39c2 ("bpf: Verifier track null pointer branch_taken with JNE and JEQ") Reported-by: Wenbo Zhang <ethercflow@gmail.com> Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200630171240.2523722-1-yhs@fb.com
2020-06-30bpf, netns: Fix use-after-free in pernet pre_exit callbackJakub Sitnicki
Iterating over BPF links attached to network namespace in pre_exit hook is not safe, even if there is just one. Once link gets auto-detached, that is its back-pointer to net object is set to NULL, the link can be released and freed without waiting on netns_bpf_mutex, effectively causing the list element we are operating on to be freed. This leads to use-after-free when trying to access the next element on the list, as reported by KASAN. Bug can be triggered by destroying a network namespace, while also releasing a link attached to this network namespace. | ================================================================== | BUG: KASAN: use-after-free in netns_bpf_pernet_pre_exit+0xd9/0x130 | Read of size 8 at addr ffff888119e0d778 by task kworker/u8:2/177 | | CPU: 3 PID: 177 Comm: kworker/u8:2 Not tainted 5.8.0-rc1-00197-ga0c04c9d1008-dirty #776 | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-buildvm-ppc64le-16.ppc.fedoraproject.org-3.fc31 04/01/2014 | Workqueue: netns cleanup_net | Call Trace: | dump_stack+0x9e/0xe0 | print_address_description.constprop.0+0x3a/0x60 | ? netns_bpf_pernet_pre_exit+0xd9/0x130 | kasan_report.cold+0x1f/0x40 | ? netns_bpf_pernet_pre_exit+0xd9/0x130 | netns_bpf_pernet_pre_exit+0xd9/0x130 | cleanup_net+0x30b/0x5b0 | ? unregister_pernet_device+0x50/0x50 | ? rcu_read_lock_bh_held+0xb0/0xb0 | ? _raw_spin_unlock_irq+0x24/0x50 | process_one_work+0x4d1/0xa10 | ? lock_release+0x3e0/0x3e0 | ? pwq_dec_nr_in_flight+0x110/0x110 | ? rwlock_bug.part.0+0x60/0x60 | worker_thread+0x7a/0x5c0 | ? process_one_work+0xa10/0xa10 | kthread+0x1e3/0x240 | ? kthread_create_on_node+0xd0/0xd0 | ret_from_fork+0x1f/0x30 | | Allocated by task 280: | save_stack+0x1b/0x40 | __kasan_kmalloc.constprop.0+0xc2/0xd0 | netns_bpf_link_create+0xfe/0x650 | __do_sys_bpf+0x153a/0x2a50 | do_syscall_64+0x59/0x300 | entry_SYSCALL_64_after_hwframe+0x44/0xa9 | | Freed by task 198: | save_stack+0x1b/0x40 | __kasan_slab_free+0x12f/0x180 | kfree+0xed/0x350 | process_one_work+0x4d1/0xa10 | worker_thread+0x7a/0x5c0 | kthread+0x1e3/0x240 | ret_from_fork+0x1f/0x30 | | The buggy address belongs to the object at ffff888119e0d700 | which belongs to the cache kmalloc-192 of size 192 | The buggy address is located 120 bytes inside of | 192-byte region [ffff888119e0d700, ffff888119e0d7c0) | The buggy address belongs to the page: | page:ffffea0004678340 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 | flags: 0x2fffe0000000200(slab) | raw: 02fffe0000000200 ffffea00045ba8c0 0000000600000006 ffff88811a80ea80 | raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 | page dumped because: kasan: bad access detected | | Memory state around the buggy address: | ffff888119e0d600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb | ffff888119e0d680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc | >ffff888119e0d700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb | ^ | ffff888119e0d780: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc | ffff888119e0d800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb | ================================================================== Remove the "fast-path" for releasing a link that got auto-detached by a dying network namespace to fix it. This way as long as link is on the list and netns_bpf mutex is held, we have a guarantee that link memory can be accessed. An alternative way to fix this issue would be to safely iterate over the list of links and ensure there is no access to link object after detaching it. But, at the moment, optimizing synchronization overhead on link release without a workload in mind seems like an overkill. Fixes: ab53cad90eb1 ("bpf, netns: Keep a list of attached bpf_link's") Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/bpf/20200630164541.1329993-1-jakub@cloudflare.com
2020-06-30bpf: sockmap: Require attach_bpf_fd when detaching a programLorenz Bauer
The sockmap code currently ignores the value of attach_bpf_fd when detaching a program. This is contrary to the usual behaviour of checking that attach_bpf_fd represents the currently attached program. Ensure that attach_bpf_fd is indeed the currently attached program. It turns out that all sockmap selftests already do this, which indicates that this is unlikely to cause breakage. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200629095630.7933-5-lmb@cloudflare.com
2020-06-30bpf: flow_dissector: Check value of unused flags to BPF_PROG_DETACHLorenz Bauer
Using BPF_PROG_DETACH on a flow dissector program supports neither attach_flags nor attach_bpf_fd. Yet no value is enforced for them. Enforce that attach_flags are zero, and require the current program to be passed via attach_bpf_fd. This allows us to remove the check for CAP_SYS_ADMIN, since userspace can now no longer remove arbitrary flow dissector programs. Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200629095630.7933-3-lmb@cloudflare.com
2020-06-30bpf: flow_dissector: Check value of unused flags to BPF_PROG_ATTACHLorenz Bauer
Using BPF_PROG_ATTACH on a flow dissector program supports neither target_fd, attach_flags or replace_bpf_fd but accepts any value. Enforce that all of them are zero. This is fine for replace_bpf_fd since its presence is indicated by BPF_F_REPLACE. It's more problematic for target_fd, since zero is a valid fd. Should we want to use the flag later on we'd have to add an exception for fd 0. The alternative is to force a value like -1. This requires more changes to tests. There is also precedent for using 0, since bpf_iter uses this for target_fd as well. Fixes: b27f7bb590ba ("flow_dissector: Move out netns_bpf prog callbacks") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200629095630.7933-2-lmb@cloudflare.com
2020-06-30bpf, netns: Keep a list of attached bpf_link'sJakub Sitnicki
To support multi-prog link-based attachments for new netns attach types, we need to keep track of more than one bpf_link per attach type. Hence, convert net->bpf.links into a list, that currently can be either empty or have just one item. Instead of reusing bpf_prog_list from bpf-cgroup, we link together bpf_netns_link's themselves. This makes list management simpler as we don't have to allocate, initialize, and later release list elements. We can do this because multi-prog attachment will be available only for bpf_link, and we don't need to build a list of programs attached directly and indirectly via links. No functional changes intended. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200625141357.910330-4-jakub@cloudflare.com
2020-06-30bpf, netns: Keep attached programs in bpf_prog_arrayJakub Sitnicki
Prepare for having multi-prog attachments for new netns attach types by storing programs to run in a bpf_prog_array, which is well suited for iterating over programs and running them in sequence. After this change bpf(PROG_QUERY) may block to allocate memory in bpf_prog_array_copy_to_user() for collected program IDs. This forces a change in how we protect access to the attached program in the query callback. Because bpf_prog_array_copy_to_user() can sleep, we switch from an RCU read lock to holding a mutex that serializes updaters. Because we allow only one BPF flow_dissector program to be attached to netns at all times, the bpf_prog_array pointed by net->bpf.run_array is always either detached (null) or one element long. No functional changes intended. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200625141357.910330-3-jakub@cloudflare.com
2020-06-30flow_dissector: Pull BPF program assignment up to bpf-netnsJakub Sitnicki
Prepare for using bpf_prog_array to store attached programs by moving out code that updates the attached program out of flow dissector. Managing bpf_prog_array is more involved than updating a single bpf_prog pointer. This will let us do it all from one place, bpf/net_namespace.c, in the subsequent patch. No functional change intended. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200625141357.910330-2-jakub@cloudflare.com
2020-06-30bpf: Enforce BPF ringbuf size to be the power of 2Andrii Nakryiko
BPF ringbuf assumes the size to be a multiple of page size and the power of 2 value. The latter is important to avoid division while calculating position inside the ring buffer and using (N-1) mask instead. This patch fixes omission to enforce power-of-2 size rule. Fixes: 457f44363a88 ("bpf: Implement BPF ring buffer and verifier support for it") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200630061500.1804799-1-andriin@fb.com
2020-06-25bpf: Do not allow btf_ctx_access with __int128 typesJohn Fastabend
To ensure btf_ctx_access() is safe the verifier checks that the BTF arg type is an int, enum, or pointer. When the function does the BTF arg lookup it uses the calculation 'arg = off / 8' using the fact that registers are 8B. This requires that the first arg is in the first reg, the second in the second, and so on. However, for __int128 the arg will consume two registers by default LLVM implementation. So this will cause the arg layout assumed by the 'arg = off / 8' calculation to be incorrect. Because __int128 is uncommon this patch applies the easiest fix and will force int types to be sizeof(u64) or smaller so that they will fit in a single register. v2: remove unneeded parens per Andrii's feedback Fixes: 9e15db66136a1 ("bpf: Implement accurate raw_tp context access via BTF") Signed-off-by: John Fastabend <john.fastabend@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/159303723962.11287.13309537171132420717.stgit@john-Precision-5820-Tower
2020-06-24bpf: Add bpf_skc_to_tcp6_sock() helperYonghong Song
The helper is used in tracing programs to cast a socket pointer to a tcp6_sock pointer. The return value could be NULL if the casting is illegal. A new helper return type RET_PTR_TO_BTF_ID_OR_NULL is added so the verifier is able to deduce proper return types for the helper. Different from the previous BTF_ID based helpers, the bpf_skc_to_tcp6_sock() argument can be several possible btf_ids. More specifically, all possible socket data structures with sock_common appearing in the first in the memory layout. This patch only added socket types related to tcp and udp. All possible argument btf_id and return value btf_id for helper bpf_skc_to_tcp6_sock() are pre-calculcated and cached. In the future, it is even possible to precompute these btf_id's at kernel build time. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/20200623230809.3988195-1-yhs@fb.com
2020-06-23bpf: Restore behaviour of CAP_SYS_ADMIN allowing the loading of networking ↵Maciej Żenczykowski
bpf programs This is a fix for a regression in commit 2c78ee898d8f ("bpf: Implement CAP_BPF"). Before the above commit it was possible to load network bpf programs with just the CAP_SYS_ADMIN privilege. The Android bpfloader happens to run in such a configuration (it has SYS_ADMIN but not NET_ADMIN) and creates maps and loads bpf programs for later use by Android's netd (which has NET_ADMIN but not SYS_ADMIN). Fixes: 2c78ee898d8f ("bpf: Implement CAP_BPF") Reported-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Tested-by: John Stultz <john.stultz@linaro.org> Link: https://lore.kernel.org/bpf/20200620212616.93894-1-zenczykowski@gmail.com
2020-06-23bpf: Set the number of exception entries properly for subprogramsYonghong Song
Currently, if a bpf program has more than one subprograms, each program will be jitted separately. For programs with bpf-to-bpf calls the prog->aux->num_exentries is not setup properly. For example, with bpf_iter_netlink.c modified to force one function to be not inlined and with CONFIG_BPF_JIT_ALWAYS_ON the following error is seen: $ ./test_progs -n 3/3 ... libbpf: failed to load program 'iter/netlink' libbpf: failed to load object 'bpf_iter_netlink' libbpf: failed to load BPF skeleton 'bpf_iter_netlink': -4007 test_netlink:FAIL:bpf_iter_netlink__open_and_load skeleton open_and_load failed #3/3 netlink:FAIL The dmesg shows the following errors: ex gen bug which is triggered by the following code in arch/x86/net/bpf_jit_comp.c: if (excnt >= bpf_prog->aux->num_exentries) { pr_err("ex gen bug\n"); return -EFAULT; } This patch fixes the issue by computing proper num_exentries for each subprogram before calling JIT. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-06-22bpf: Set map_btf_{name, id} for all map typesAndrey Ignatov
Set map_btf_name and map_btf_id for all map types so that map fields can be accessed by bpf programs. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/a825f808f22af52b018dbe82f1c7d29dab5fc978.1592600985.git.rdna@fb.com
2020-06-22bpf: Support access to bpf map fieldsAndrey Ignatov
There are multiple use-cases when it's convenient to have access to bpf map fields, both `struct bpf_map` and map type specific struct-s such as `struct bpf_array`, `struct bpf_htab`, etc. For example while working with sock arrays it can be necessary to calculate the key based on map->max_entries (some_hash % max_entries). Currently this is solved by communicating max_entries via "out-of-band" channel, e.g. via additional map with known key to get info about target map. That works, but is not very convenient and error-prone while working with many maps. In other cases necessary data is dynamic (i.e. unknown at loading time) and it's impossible to get it at all. For example while working with a hash table it can be convenient to know how much capacity is already used (bpf_htab.count.counter for BPF_F_NO_PREALLOC case). At the same time kernel knows this info and can provide it to bpf program. Fill this gap by adding support to access bpf map fields from bpf program for both `struct bpf_map` and map type specific fields. Support is implemented via btf_struct_access() so that a user can define their own `struct bpf_map` or map type specific struct in their program with only necessary fields and preserve_access_index attribute, cast a map to this struct and use a field. For example: struct bpf_map { __u32 max_entries; } __attribute__((preserve_access_index)); struct bpf_array { struct bpf_map map; __u32 elem_size; } __attribute__((preserve_access_index)); struct { __uint(type, BPF_MAP_TYPE_ARRAY); __uint(max_entries, 4); __type(key, __u32); __type(value, __u32); } m_array SEC(".maps"); SEC("cgroup_skb/egress") int cg_skb(void *ctx) { struct bpf_array *array = (struct bpf_array *)&m_array; struct bpf_map *map = (struct bpf_map *)&m_array; /* .. use map->max_entries or array->map.max_entries .. */ } Similarly to other btf_struct_access() use-cases (e.g. struct tcp_sock in net/ipv4/bpf_tcp_ca.c) the patch allows access to any fields of corresponding struct. Only reading from map fields is supported. For btf_struct_access() to work there should be a way to know btf id of a struct that corresponds to a map type. To get btf id there should be a way to get a stringified name of map-specific struct, such as "bpf_array", "bpf_htab", etc for a map type. Two new fields are added to `struct bpf_map_ops` to handle it: * .map_btf_name keeps a btf name of a struct returned by map_alloc(); * .map_btf_id is used to cache btf id of that struct. To make btf ids calculation cheaper they're calculated once while preparing btf_vmlinux and cached same way as it's done for btf_id field of `struct bpf_func_proto` While calculating btf ids, struct names are NOT checked for collision. Collisions will be checked as a part of the work to prepare btf ids used in verifier in compile time that should land soon. The only known collision for `struct bpf_htab` (kernel/bpf/hashtab.c vs net/core/sock_map.c) was fixed earlier. Both new fields .map_btf_name and .map_btf_id must be set for a map type for the feature to work. If neither is set for a map type, verifier will return ENOTSUPP on a try to access map_ptr of corresponding type. If just one of them set, it's verifier misconfiguration. Only `struct bpf_array` for BPF_MAP_TYPE_ARRAY and `struct bpf_htab` for BPF_MAP_TYPE_HASH are supported by this patch. Other map types will be supported separately. The feature is available only for CONFIG_DEBUG_INFO_BTF=y and gated by perfmon_capable() so that unpriv programs won't have access to bpf map fields. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/6479686a0cd1e9067993df57b4c3eef0e276fec9.1592600985.git.rdna@fb.com
2020-06-22bpf: Switch btf_parse_vmlinux to btf_find_by_name_kindAndrey Ignatov
btf_parse_vmlinux() implements manual search for struct bpf_ctx_convert since at the time of implementing btf_find_by_name_kind() was not available. Later btf_find_by_name_kind() was introduced in 27ae7997a661 ("bpf: Introduce BPF_PROG_TYPE_STRUCT_OPS"). It provides similar search functionality and can be leveraged in btf_parse_vmlinux(). Do it. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Andrii Nakryiko <andriin@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/6e12d5c3e8a3d552925913ef73a695dd1bb27800.1592600985.git.rdna@fb.com
2020-06-19bpf: Avoid verifier failure for 32bit pointer arithmeticYonghong Song
When do experiments with llvm (disabling instcombine and simplifyCFG), I hit the following error with test_seg6_loop.o. ; R1=pkt(id=0,off=0,r=48,imm=0), R7=pkt(id=0,off=40,r=48,imm=0) w2 = w7 ; R2_w=inv(id=0,umax_value=4294967295,var_off=(0x0; 0xffffffff)) w2 -= w1 R2 32-bit pointer arithmetic prohibited The corresponding source code is: uint32_t srh_off // srh and skb->data are all packet pointers srh_off = (char *)srh - (char *)(long)skb->data; The verifier does not support 32-bit pointer/scalar arithmetic. Without my llvm change, the code looks like ; R3=pkt(id=0,off=40,r=48,imm=0), R8=pkt(id=0,off=0,r=48,imm=0) w3 -= w8 ; R3_w=inv(id=0) This is explicitly allowed in verifier if both registers are pointers and the opcode is BPF_SUB. To fix this problem, I changed the verifier to allow 32-bit pointer/scaler BPF_SUB operations. At the source level, the issue could be workarounded with inline asm or changing "uint32_t srh_off" to "uint64_t srh_off". But I feel that verifier change might be the right thing to do. Signed-off-by: Yonghong Song <yhs@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200618234631.3321118-1-yhs@fb.com
2020-06-17bpf: Don't return EINVAL from {get,set}sockopt when optlen > PAGE_SIZEStanislav Fomichev
Attaching to these hooks can break iptables because its optval is usually quite big, or at least bigger than the current PAGE_SIZE limit. David also mentioned some SCTP options can be big (around 256k). For such optvals we expose only the first PAGE_SIZE bytes to the BPF program. BPF program has two options: 1. Set ctx->optlen to 0 to indicate that the BPF's optval should be ignored and the kernel should use original userspace value. 2. Set ctx->optlen to something that's smaller than the PAGE_SIZE. v5: * use ctx->optlen == 0 with trimmed buffer (Alexei Starovoitov) * update the docs accordingly v4: * use temporary buffer to avoid optval == optval_end == NULL; this removes the corner case in the verifier that might assume non-zero PTR_TO_PACKET/PTR_TO_PACKET_END. v3: * don't increase the limit, bypass the argument v2: * proper comments formatting (Jakub Kicinski) Fixes: 0d01da6afc54 ("bpf: implement getsockopt and setsockopt hooks") Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Cc: David Laight <David.Laight@ACULAB.COM> Link: https://lore.kernel.org/bpf/20200617010416.93086-1-sdf@google.com
2020-06-17devmap: Use bpf_map_area_alloc() for allocating hash bucketsToke Høiland-Jørgensen
Syzkaller discovered that creating a hash of type devmap_hash with a large number of entries can hit the memory allocator limit for allocating contiguous memory regions. There's really no reason to use kmalloc_array() directly in the devmap code, so just switch it to the existing bpf_map_area_alloc() function that is used elsewhere. Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index") Reported-by: Xiumei Mu <xmu@redhat.com> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20200616142829.114173-1-toke@redhat.com
2020-06-13Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netLinus Torvalds
Pull networking fixes from David Miller: 1) Fix cfg80211 deadlock, from Johannes Berg. 2) RXRPC fails to send norigications, from David Howells. 3) MPTCP RM_ADDR parsing has an off by one pointer error, fix from Geliang Tang. 4) Fix crash when using MSG_PEEK with sockmap, from Anny Hu. 5) The ucc_geth driver needs __netdev_watchdog_up exported, from Valentin Longchamp. 6) Fix hashtable memory leak in dccp, from Wang Hai. 7) Fix how nexthops are marked as FDB nexthops, from David Ahern. 8) Fix mptcp races between shutdown and recvmsg, from Paolo Abeni. 9) Fix crashes in tipc_disc_rcv(), from Tuong Lien. 10) Fix link speed reporting in iavf driver, from Brett Creeley. 11) When a channel is used for XSK and then reused again later for XSK, we forget to clear out the relevant data structures in mlx5 which causes all kinds of problems. Fix from Maxim Mikityanskiy. 12) Fix memory leak in genetlink, from Cong Wang. 13) Disallow sockmap attachments to UDP sockets, it simply won't work. From Lorenz Bauer. * git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (83 commits) net: ethernet: ti: ale: fix allmulti for nu type ale net: ethernet: ti: am65-cpsw-nuss: fix ale parameters init net: atm: Remove the error message according to the atomic context bpf: Undo internal BPF_PROBE_MEM in BPF insns dump libbpf: Support pre-initializing .bss global variables tools/bpftool: Fix skeleton codegen bpf: Fix memlock accounting for sock_hash bpf: sockmap: Don't attach programs to UDP sockets bpf: tcp: Recv() should return 0 when the peer socket is closed ibmvnic: Flush existing work items before device removal genetlink: clean up family attributes allocations net: ipa: header pad field only valid for AP->modem endpoint net: ipa: program upper nibbles of sequencer type net: ipa: fix modem LAN RX endpoint id net: ipa: program metadata mask differently ionic: add pcie_print_link_status rxrpc: Fix race between incoming ACK parser and retransmitter net/mlx5: E-Switch, Fix some error pointer dereferences net/mlx5: Don't fail driver on failure to create debugfs net/mlx5e: CT: Fix ipv6 nat header rewrite actions ...
2020-06-12bpf: Undo internal BPF_PROBE_MEM in BPF insns dumpAndrii Nakryiko
BPF_PROBE_MEM is kernel-internal implmementation details. When dumping BPF instructions to user-space, it needs to be replaced back with BPF_MEM mode. Fixes: 2a02759ef5f8 ("bpf: Add support for BTF pointers to interpreter") Signed-off-by: Andrii Nakryiko <andriin@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200613002115.1632142-1-andriin@fb.com
2020-06-10Merge branch 'uaccess.misc' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull misc uaccess updates from Al Viro: "Assorted uaccess patches for this cycle - the stuff that didn't fit into thematic series" * 'uaccess.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() x86: kvm_hv_set_msr(): use __put_user() instead of 32bit __clear_user() user_regset_copyout_zero(): use clear_user() TEST_ACCESS_OK _never_ had been checked anywhere x86: switch cp_stat64() to unsafe_put_user() binfmt_flat: don't use __put_user() binfmt_elf_fdpic: don't use __... uaccess primitives binfmt_elf: don't bother with __{put,copy_to}_user() pselect6() and friends: take handling the combined 6th/7th args into helper
2020-06-09bpf: Devmap adjust uapi for attach bpf programJesper Dangaard Brouer
V2: - Defer changing BPF-syscall to start at file-descriptor 1 - Use {} to zero initialise struct. The recent commit fbee97feed9b ("bpf: Add support to attach bpf program to a devmap entry"), introduced ability to attach (and run) a separate XDP bpf_prog for each devmap entry. A bpf_prog is added via a file-descriptor. As zero were a valid FD, not using the feature requires using value minus-1. The UAPI is extended via tail-extending struct bpf_devmap_val and using map->value_size to determine the feature set. This will break older userspace applications not using the bpf_prog feature. Consider an old userspace app that is compiled against newer kernel uapi/bpf.h, it will not know that it need to initialise the member bpf_prog.fd to minus-1. Thus, users will be forced to update source code to get program running on newer kernels. This patch remove the minus-1 checks, and have zero mean feature isn't used. Followup patches either for kernel or libbpf should handle and avoid returning file-descriptor zero in the first place. Fixes: fbee97feed9b ("bpf: Add support to attach bpf program to a devmap entry") Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/159170950687.2102545.7235914718298050113.stgit@firesoul
2020-06-09bpf: cgroup: Allow multi-attach program to replace itselfLorenz Bauer
When using BPF_PROG_ATTACH to attach a program to a cgroup in BPF_F_ALLOW_MULTI mode, it is not possible to replace a program with itself. This is because the check for duplicate programs doesn't take the replacement program into account. Replacing a program with itself might seem weird, but it has some uses: first, it allows resetting the associated cgroup storage. Second, it makes the API consistent with the non-ALLOW_MULTI usage, where it is possible to replace a program with itself. Third, it aligns BPF_PROG_ATTACH with bpf_link, where replacing itself is also supported. Sice this code has been refactored a few times this change will only apply to v5.7 and later. Adjustments could be made to commit 1020c1f24a94 ("bpf: Simplify __cgroup_bpf_attach") and commit d7bf2c10af05 ("bpf: allocate cgroup storage entries on attaching bpf programs") as well as commit 324bda9e6c5a ("bpf: multi program support for cgroup+bpf") Fixes: af6eea57437a ("bpf: Implement bpf_link-based cgroup BPF program attachment") Signed-off-by: Lorenz Bauer <lmb@cloudflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200608162202.94002-1-lmb@cloudflare.com
2020-06-09bpf: Reset data_meta before running programs attached to devmap entryDavid Ahern
This is a new context that does not handle metadata at the moment, so mark data_meta invalid. Fixes: fbee97feed9b ("bpf: Add support to attach bpf program to a devmap entry") Signed-off-by: David Ahern <dsahern@kernel.org> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200608151723.9539-1-dsahern@kernel.org
2020-06-09mmap locking API: add mmap_read_trylock_non_owner()Michel Lespinasse
Add a couple APIs used by kernel/bpf/stackmap.c only: - mmap_read_trylock_non_owner() - mmap_read_unlock_non_owner() (may be called from a work queue). It's still not ideal that bpf/stackmap subverts the lock ownership in this way. Thanks to Peter Zijlstra for suggesting this API as the least-ugly way of addressing this in the short term. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-8-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>