kernel.git/arch/x86/net, branch linux-4.14.y

bpf, x86: Validate computation of branch displacements for x86-64

2021-04-10T11:20:11Z

commit e4d4d456436bfb2fe412ee2cd489f7658449b098 upstream. The branch displacement logic in the BPF JIT compilers for x86 assumes that, for any generated branch instruction, the distance cannot increase between optimization passes. But this assumption can be violated due to how the distances are computed. Specifically, whenever a backward branch is processed in do_jit(), the distance is computed by subtracting the positions in the machine code from different optimization passes. This is because part of addrs[] is already updated for the current optimization pass, before the branch instruction is visited. And so the optimizer can expand blocks of machine code in some cases. This can confuse the optimizer logic, where it assumes that a fixed point has been reached for all machine code blocks once the total program size stops changing. And then the JIT compiler can output abnormal machine code containing incorrect branch displacements. To mitigate this issue, we assert that a fixed point is reached while populating the output image. This rejects any problematic programs. The issue affects both x86-32 and x86-64. We mitigate separately to ease backporting. Signed-off-by: Piotr Krysiuk Reviewed-by: Daniel Borkmann Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf, x86: Fix encoding for lower 8-bit registers in BPF_STX BPF_B

2020-05-02T15:24:42Z

[ Upstream commit aee194b14dd2b2bde6252b3acf57d36dccfc743a ] This patch fixes an encoding bug in emit_stx for BPF_B when the source register is BPF_REG_FP. The current implementation for BPF_STX BPF_B in emit_stx saves one REX byte when the operands can be encoded using Mod-R/M alone. The lower 8 bits of registers %rax, %rbx, %rcx, and %rdx can be accessed without using a REX prefix via %al, %bl, %cl, and %dl, respectively. Other registers, (e.g., %rsi, %rdi, %rbp, %rsp) require a REX prefix to use their 8-bit equivalents (%sil, %dil, %bpl, %spl). The current code checks if the source for BPF_STX BPF_B is BPF_REG_1 or BPF_REG_2 (which map to %rdi and %rsi), in which case it emits the required REX prefix. However, it misses the case when the source is BPF_REG_FP (mapped to %rbp). The result is that BPF_STX BPF_B with BPF_REG_FP as the source operand will read from register %ch instead of the correct %bpl. This patch fixes the problem by fixing and refactoring the check on which registers need the extra REX byte. Since no BPF registers map to %rsp, there is no need to handle %spl. Fixes: 622582786c9e0 ("net: filter: x86: internal BPF JIT") Signed-off-by: Xi Wang Signed-off-by: Luke Nelson Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20200418232655.23870-1-luke.r.nels@gmail.com Signed-off-by: Sasha Levin

bpf: get rid of pure_initcall dependency to enable jits

2019-08-25T08:50:02Z

commit fa9dd599b4dae841924b022768354cfde9affecb upstream. Having a pure_initcall() callback just to permanently enable BPF JITs under CONFIG_BPF_JIT_ALWAYS_ON is unnecessary and could leave a small race window in future where JIT is still disabled on boot. Since we know about the setting at compilation time anyway, just initialize it properly there. Also consolidate all the individual bpf_jit_enable variables into a single one and move them under one location. Moreover, don't allow for setting unspecified garbage values on them. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: Alexei Starovoitov [bwh: Backported to 4.14 as dependency of commit 2e4a30983b0f "bpf: restrict access to core bpf sysctls": - Adjust context] Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman

bpf, x64: fix memleak when not converging after image

2018-06-20T19:02:52Z

[ Upstream commit 3aab8884c9eb99189a3569ac4e6b205371c9ac0b ] While reviewing x64 JIT code, I noticed that we leak the prior allocated JIT image in the case where proglen != oldproglen during the JIT passes. Prior to the commit e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") we would just break out of the loop, and using the image as the JITed prog since it could only shrink in size anyway. After e0ee9c12157d, we would bail out to out_addrs label where we free addrs and jit_data but not the image coming from bpf_jit_binary_alloc(). Fixes: e0ee9c12157d ("x86: bpf_jit: fix two bugs in eBPF JIT compiler") Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Acked-by: David S. Miller Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

bpf, x64: increase number of passes

2018-03-28T16:24:51Z

commit 6007b080d2e2adb7af22bf29165f0594ea12b34c upstream. In Cilium some of the main programs we run today are hitting 9 passes on x64's JIT compiler, and we've had cases already where we surpassed the limit where the JIT then punts the program to the interpreter instead, leading to insertion failures due to CONFIG_BPF_JIT_ALWAYS_ON or insertion failures due to the prog array owner being JITed but the program to insert not (both must have the same JITed/non-JITed property). One concrete case the program image shrunk from 12,767 bytes down to 10,288 bytes where the image converged after 16 steps. I've measured that this took 340us in the JIT until it converges on my i7-6600U. Thus, increase the original limit we had from day one where the JIT covered cBPF only back then before we run into the case (as similar with the complexity limit) where we trip over this and hit program rejections. Also add a cond_resched() into the compilation loop, the JIT process runs without any locks and may sleep anyway. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Reviewed-by: Eric Dumazet Signed-off-by: Alexei Starovoitov Signed-off-by: Greg Kroah-Hartman

bpf, x64: implement retpoline for tail call

2018-03-11T15:23:22Z

[ upstream commit a493a87f38cfa48caaa95c9347be2d914c6fdf29 ] Implement a retpoline [0] for the BPF tail call JIT'ing that converts the indirect jump via jmp %rax that is used to make the long jump into another JITed BPF image. Since this is subject to speculative execution, we need to control the transient instruction sequence here as well when CONFIG_RETPOLINE is set, and direct it into a pause + lfence loop. The latter aligns also with what gcc / clang emits (e.g. [1]). JIT dump after patch: # bpftool p d x i 1 0: (18) r2 = map[id:1] 2: (b7) r3 = 0 3: (85) call bpf_tail_call#12 4: (b7) r0 = 2 5: (95) exit With CONFIG_RETPOLINE: # bpftool p d j i 1 [...] 33: cmp %edx,0x24(%rsi) 36: jbe 0x0000000000000072 |* 38: mov 0x24(%rbp),%eax 3e: cmp $0x20,%eax 41: ja 0x0000000000000072 | 43: add $0x1,%eax 46: mov %eax,0x24(%rbp) 4c: mov 0x90(%rsi,%rdx,8),%rax 54: test %rax,%rax 57: je 0x0000000000000072 | 59: mov 0x28(%rax),%rax 5d: add $0x25,%rax 61: callq 0x000000000000006d |+ 66: pause | 68: lfence | 6b: jmp 0x0000000000000066 | 6d: mov %rax,(%rsp) | 71: retq | 72: mov $0x2,%eax [...] * relative fall-through jumps in error case + retpoline for indirect jump Without CONFIG_RETPOLINE: # bpftool p d j i 1 [...] 33: cmp %edx,0x24(%rsi) 36: jbe 0x0000000000000063 |* 38: mov 0x24(%rbp),%eax 3e: cmp $0x20,%eax 41: ja 0x0000000000000063 | 43: add $0x1,%eax 46: mov %eax,0x24(%rbp) 4c: mov 0x90(%rsi,%rdx,8),%rax 54: test %rax,%rax 57: je 0x0000000000000063 | 59: mov 0x28(%rax),%rax 5d: add $0x25,%rax 61: jmpq *%rax |- 63: mov $0x2,%eax [...] * relative fall-through jumps in error case - plain indirect jump as before [0] https://support.google.com/faqs/answer/7625886 [1] https://github.com/gcc-mirror/gcc/commit/a31e654fa107be968b802786d747e962c2fcdb2b Signed-off-by: Daniel Borkmann Signed-off-by: Alexei Starovoitov Signed-off-by: Daniel Borkmann Signed-off-by: Greg Kroah-Hartman

bpf: fix bpf_tail_call() x64 JIT

2017-10-03T23:04:44Z

- bpf prog_array just like all other types of bpf array accepts 32-bit index. Clarify that in the comment. - fix x64 JIT of bpf_tail_call which was incorrectly loading 8 instead of 4 bytes - tighten corresponding check in the interpreter to stay consistent The JIT bug can be triggered after introduction of BPF_F_NUMA_NODE flag in commit 96eabe7a40aa in 4.14. Before that the map_flags would stay zero and though JIT code is wrong it will check bounds correctly. Hence two fixes tags. All other JITs don't have this problem. Signed-off-by: Alexei Starovoitov Fixes: 96eabe7a40aa ("bpf: Allow selecting numa node during map creation") Fixes: b52f00e6a715 ("x86: bpf_jit: implement bpf_tail_call() helper") Acked-by: Daniel Borkmann Acked-by: Martin KaFai Lau Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

x86: bpf_jit: small optimization in emit_bpf_tail_call()

2017-08-31T18:57:37Z

Saves 4 bytes replacing following instructions : lea rax, [rsi + rdx * 8 + offsetof(...)] mov rax, qword ptr [rax] cmp rax, 0 by : mov rax, [rsi + rdx * 8 + offsetof(...)] test rax, rax Signed-off-by: Eric Dumazet Cc: Alexei Starovoitov Cc: Daniel Borkmann Acked-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

bpf, x86: implement jiting of BPF_J{LT,LE,SLT,SLE}

2017-08-09T23:53:56Z

This work implements jiting of BPF_J{LT,LE,SLT,SLE} instructions with BPF_X/BPF_K variants for the x86_64 eBPF JIT. Signed-off-by: Daniel Borkmann Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next

2017-07-05T19:31:59Z

Pull networking updates from David Miller: "Reasonably busy this cycle, but perhaps not as busy as in the 4.12 merge window: 1) Several optimizations for UDP processing under high load from Paolo Abeni. 2) Support pacing internally in TCP when using the sch_fq packet scheduler for this is not practical. From Eric Dumazet. 3) Support mutliple filter chains per qdisc, from Jiri Pirko. 4) Move to 1ms TCP timestamp clock, from Eric Dumazet. 5) Add batch dequeueing to vhost_net, from Jason Wang. 6) Flesh out more completely SCTP checksum offload support, from Davide Caratti. 7) More plumbing of extended netlink ACKs, from David Ahern, Pablo Neira Ayuso, and Matthias Schiffer. 8) Add devlink support to nfp driver, from Simon Horman. 9) Add RTM_F_FIB_MATCH flag to RTM_GETROUTE queries, from Roopa Prabhu. 10) Add stack depth tracking to BPF verifier and use this information in the various eBPF JITs. From Alexei Starovoitov. 11) Support XDP on qed device VFs, from Yuval Mintz. 12) Introduce BPF PROG ID for better introspection of installed BPF programs. From Martin KaFai Lau. 13) Add bpf_set_hash helper for TC bpf programs, from Daniel Borkmann. 14) For loads, allow narrower accesses in bpf verifier checking, from Yonghong Song. 15) Support MIPS in the BPF selftests and samples infrastructure, the MIPS eBPF JIT will be merged in via the MIPS GIT tree. From David Daney. 16) Support kernel based TLS, from Dave Watson and others. 17) Remove completely DST garbage collection, from Wei Wang. 18) Allow installing TCP MD5 rules using prefixes, from Ivan Delalande. 19) Add XDP support to Intel i40e driver, from Björn Töpel 20) Add support for TC flower offload in nfp driver, from Simon Horman, Pieter Jansen van Vuuren, Benjamin LaHaise, Jakub Kicinski, and Bert van Leeuwen. 21) IPSEC offloading support in mlx5, from Ilan Tayari. 22) Add HW PTP support to macb driver, from Rafal Ozieblo. 23) Networking refcount_t conversions, From Elena Reshetova. 24) Add sock_ops support to BPF, from Lawrence Brako. This is useful for tuning the TCP sockopt settings of a group of applications, currently via CGROUPs" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1899 commits) net: phy: dp83867: add workaround for incorrect RX_CTRL pin strap dt-bindings: phy: dp83867: provide a workaround for incorrect RX_CTRL pin strap cxgb4: Support for get_ts_info ethtool method cxgb4: Add PTP Hardware Clock (PHC) support cxgb4: time stamping interface for PTP nfp: default to chained metadata prepend format nfp: remove legacy MAC address lookup nfp: improve order of interfaces in breakout mode net: macb: remove extraneous return when MACB_EXT_DESC is defined bpf: add missing break in for the TCP_BPF_SNDCWND_CLAMP case bpf: fix return in load_bpf_file mpls: fix rtm policy in mpls_getroute net, ax25: convert ax25_cb.refcount from atomic_t to refcount_t net, ax25: convert ax25_route.refcount from atomic_t to refcount_t net, ax25: convert ax25_uid_assoc.refcount from atomic_t to refcount_t net, sctp: convert sctp_ep_common.refcnt from atomic_t to refcount_t net, sctp: convert sctp_transport.refcnt from atomic_t to refcount_t net, sctp: convert sctp_chunk.refcnt from atomic_t to refcount_t net, sctp: convert sctp_datamsg.refcnt from atomic_t to refcount_t net, sctp: convert sctp_auth_bytes.refcnt from atomic_t to refcount_t ...