kernel.git/arch/x86/net, branch linux-5.18.y

bpf, x86: fix freeing of not-finalized bpf_prog_pack

2022-08-17T12:41:04Z

[ Upstream commit 1d5f82d9dd477d5c66e0214a68c3e4f308eadd6d ] syzbot reported a few issues with bpf_prog_pack [1], [2]. This only happens with multiple subprogs. In jit_subprogs(), we first call bpf_int_jit_compile() on each sub program. And then, we call it on each sub program again. jit_data is not freed in the first call of bpf_int_jit_compile(). Similarly we don't call bpf_jit_binary_pack_finalize() in the first call of bpf_int_jit_compile(). If bpf_int_jit_compile() failed for one sub program, we will call bpf_jit_binary_pack_finalize() for this sub program. However, we don't have a chance to call it for other sub programs. Then we will hit "goto out_free" in jit_subprogs(), and call bpf_jit_free on some subprograms that haven't got bpf_jit_binary_pack_finalize() yet. At this point, bpf_jit_binary_pack_free() is called and the whole 2MB page is freed erroneously. Fix this with a custom bpf_jit_free() for x86_64, which calls bpf_jit_binary_pack_finalize() if necessary. Also, with custom bpf_jit_free(), bpf_prog_aux->use_bpf_prog_pack is not needed any more, remove it. Fixes: 1022a5498f6f ("bpf, x86_64: Use bpf_jit_binary_pack_alloc") [1] https://syzkaller.appspot.com/bug?extid=2f649ec6d2eea1495a8f [2] https://syzkaller.appspot.com/bug?extid=87f65c75f4a72db05445 Reported-by: syzbot+2f649ec6d2eea1495a8f@syzkaller.appspotmail.com Reported-by: syzbot+87f65c75f4a72db05445@syzkaller.appspotmail.com Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20220706002612.4013790-1-song@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf, x64: Add predicate for bpf2bpf with tailcalls support in JIT

2022-08-17T12:41:04Z

[ Upstream commit 95acd8817e66d031d2e6ee7def3f1e1874819317 ] The BPF core/verifier is hard-coded to permit mixing bpf2bpf and tail calls for only x86-64. Change the logic to instead rely on a new weak function 'bool bpf_jit_supports_subprog_tailcalls(void)', which a capable JIT backend can override. Update the x86-64 eBPF JIT to reflect this. Signed-off-by: Tony Ambardar [jakub: drop MIPS bits and tweak patch subject] Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220617105735.733938-2-jakub@cloudflare.com Signed-off-by: Sasha Levin

bpf, x86: Generate trampolines from bpf_tramp_links

2022-08-17T12:41:04Z

[ Upstream commit f7e0beaf39d3868dc700d4954b26cf8443c5d423 ] Replace struct bpf_tramp_progs with struct bpf_tramp_links to collect struct bpf_tramp_link(s) for a trampoline. struct bpf_tramp_link extends bpf_link to act as a linked list node. arch_prepare_bpf_trampoline() accepts a struct bpf_tramp_links to collects all bpf_tramp_link(s) that a trampoline should call. Change BPF trampoline and bpf_struct_ops to pass bpf_tramp_links instead of bpf_tramp_progs. Signed-off-by: Kui-Feng Lee Signed-off-by: Alexei Starovoitov Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220510205923.3206889-2-kuifeng@fb.com Signed-off-by: Sasha Levin

x86/bpf: Use alternative RET encoding

2022-07-23T10:56:44Z

commit d77cfe594ad50e0bf95d457e02ccd578791b2a15 upstream. Use the return thunk in eBPF generated code, if needed. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

x86/retpoline: Cleanup some #ifdefery

2022-07-23T10:56:42Z

commit 369ae6ffc41a3c1137cab697635a84d0cc7cdcea upstream. On it's own not much of a cleanup but it prepares for more/similar code. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Borislav Petkov Reviewed-by: Borislav Petkov Reviewed-by: Josh Poimboeuf Signed-off-by: Borislav Petkov Signed-off-by: Thadeu Lima de Souza Cascardo Signed-off-by: Greg Kroah-Hartman

bpf, x86: Fix tail call count offset calculation on bpf2bpf call

2022-06-29T07:04:30Z

[ Upstream commit ff672c67ee7635ca1e28fb13729e8ef0d1f08ce5 ] On x86-64 the tail call count is passed from one BPF function to another through %rax. Additionally, on function entry, the tail call count value is stored on stack right after the BPF program stack, due to register shortage. The stored count is later loaded from stack either when performing a tail call - to check if we have not reached the tail call limit - or before calling another BPF function call in order to pass it via %rax. In the latter case, we miscalculate the offset at which the tail call count was stored on function entry. The JIT does not take into account that the allocated BPF program stack is always a multiple of 8 on x86, while the actual stack depth does not have to be. This leads to a load from an offset that belongs to the BPF stack, as shown in the example below: SEC("tc") int entry(struct __sk_buff *skb) { /* Have data on stack which size is not a multiple of 8 */ volatile char arr[1] = {}; return subprog_tail(skb); } int entry(struct __sk_buff * skb): 0: (b4) w2 = 0 1: (73) *(u8 *)(r10 -1) = r2 2: (85) call pc+1#bpf_prog_ce2f79bb5f3e06dd_F 3: (95) exit int entry(struct __sk_buff * skb): 0xffffffffa0201788: nop DWORD PTR [rax+rax*1+0x0] 0xffffffffa020178d: xor eax,eax 0xffffffffa020178f: push rbp 0xffffffffa0201790: mov rbp,rsp 0xffffffffa0201793: sub rsp,0x8 0xffffffffa020179a: push rax 0xffffffffa020179b: xor esi,esi 0xffffffffa020179d: mov BYTE PTR [rbp-0x1],sil 0xffffffffa02017a1: mov rax,QWORD PTR [rbp-0x9] !!! tail call count 0xffffffffa02017a8: call 0xffffffffa02017d8 !!! is at rbp-0x10 0xffffffffa02017ad: leave 0xffffffffa02017ae: ret Fix it by rounding up the BPF stack depth to a multiple of 8, when calculating the tail call count offset on stack. Fixes: ebf7d1f508a7 ("bpf, x64: rework pro/epilogue and tailcall handling in JIT") Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Acked-by: Maciej Fijalkowski Acked-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220616162037.535469-2-jakub@cloudflare.com Signed-off-by: Sasha Levin

x86,bpf: Avoid IBT objtool warning

2022-04-07T09:27:02Z

Clang can inline emit_indirect_jump() and then folds constants, which results in: | vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x6a4: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40 | vmlinux.o: warning: objtool: emit_bpf_dispatcher()+0x67d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x40 | vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x386: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20 | vmlinux.o: warning: objtool: emit_bpf_tail_call_indirect()+0x35d: relocation to !ENDBR: .text.__x86.indirect_thunk+0x20 Suppress the optimization such that it must emit a code reference to the __x86_indirect_thunk_array[] base. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Alexei Starovoitov Link: https://lkml.kernel.org/r/20220405075531.GB30877@worktop.programming.kicks-ass.net

Merge tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2022-03-27T17:17:23Z

Pull x86 CET-IBT (Control-Flow-Integrity) support from Peter Zijlstra: "Add support for Intel CET-IBT, available since Tigerlake (11th gen), which is a coarse grained, hardware based, forward edge Control-Flow-Integrity mechanism where any indirect CALL/JMP must target an ENDBR instruction or suffer #CP. Additionally, since Alderlake (12th gen)/Sapphire-Rapids, speculation is limited to 2 instructions (and typically fewer) on branch targets not starting with ENDBR. CET-IBT also limits speculation of the next sequential instruction after the indirect CALL/JMP [1]. CET-IBT is fundamentally incompatible with retpolines, but provides, as described above, speculation limits itself" [1] https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/technical-documentation/branch-history-injection.html * tag 'x86_core_for_5.18_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (53 commits) kvm/emulate: Fix SETcc emulation for ENDBR x86/Kconfig: Only allow CONFIG_X86_KERNEL_IBT with ld.lld >= 14.0.0 x86/Kconfig: Only enable CONFIG_CC_HAS_IBT for clang >= 14.0.0 kbuild: Fixup the IBT kbuild changes x86/Kconfig: Do not allow CONFIG_X86_X32_ABI=y with llvm-objcopy x86: Remove toolchain check for X32 ABI capability x86/alternative: Use .ibt_endbr_seal to seal indirect calls objtool: Find unused ENDBR instructions objtool: Validate IBT assumptions objtool: Add IBT/ENDBR decoding objtool: Read the NOENDBR annotation x86: Annotate idtentry_df() x86,objtool: Move the ASM_REACHABLE annotation to objtool.h x86: Annotate call_on_stack() objtool: Rework ASM_REACHABLE x86: Mark __invalid_creds() __noreturn exit: Mark do_group_exit() __noreturn x86: Mark stop_this_cpu() __noreturn objtool: Ignore extra-symbol code objtool: Rename --duplicate to --lto ...

Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

2022-03-22T18:18:49Z

Alexei Starovoitov says: ==================== pull-request: bpf-next 2022-03-21 v2 We've added 137 non-merge commits during the last 17 day(s) which contain a total of 143 files changed, 7123 insertions(+), 1092 deletions(-). The main changes are: 1) Custom SEC() handling in libbpf, from Andrii. 2) subskeleton support, from Delyan. 3) Use btf_tag to recognize __percpu pointers in the verifier, from Hao. 4) Fix net.core.bpf_jit_harden race, from Hou. 5) Fix bpf_sk_lookup remote_port on big-endian, from Jakub. 6) Introduce fprobe (multi kprobe) _without_ arch bits, from Masami. The arch specific bits will come later. 7) Introduce multi_kprobe bpf programs on top of fprobe, from Jiri. 8) Enable non-atomic allocations in local storage, from Joanne. 9) Various var_off ptr_to_btf_id fixed, from Kumar. 10) bpf_ima_file_hash helper, from Roberto. 11) Add "live packet" mode for XDP in BPF_PROG_RUN, from Toke. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (137 commits) selftests/bpf: Fix kprobe_multi test. Revert "rethook: x86: Add rethook x86 implementation" Revert "arm64: rethook: Add arm64 rethook implementation" Revert "powerpc: Add rethook support" Revert "ARM: rethook: Add rethook arm implementation" bpftool: Fix a bug in subskeleton code generation bpf: Fix bpf_prog_pack when PMU_SIZE is not defined bpf: Fix bpf_prog_pack for multi-node setup bpf: Fix warning for cast from restricted gfp_t in verifier bpf, arm: Fix various typos in comments libbpf: Close fd in bpf_object__reuse_map bpftool: Fix print error when show bpf map bpf: Fix kprobe_multi return probe backtrace Revert "bpf: Add support to inline bpf_get_func_ip helper on x86" bpf: Simplify check in btf_parse_hdr() selftests/bpf/test_lirc_mode2.sh: Exit with proper code bpf: Check for NULL return from bpf_get_btf_vmlinux selftests/bpf: Test skipping stacktrace bpf: Adjust BPF stack helper functions to accommodate skip > 0 bpf: Select proper size for bpf_prog_pack ... ==================== Link: https://lore.kernel.org/r/20220322050159.5507-1-alexei.starovoitov@gmail.com Signed-off-by: Jakub Kicinski

bpf, x86: Fall back to interpreter mode when extra pass fails

2022-03-16T22:12:18Z

Extra pass for subprog jit may fail (e.g. due to bpf_jit_harden race), but bpf_func is not cleared for the subprog and jit_subprogs will succeed. The running of the bpf program may lead to oops because the memory for the jited subprog image has already been freed. So fall back to interpreter mode by clearing bpf_func/jited/jited_len when extra pass fails. Signed-off-by: Hou Tao Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20220309123321.2400262-2-houtao1@huawei.com