kernel.git/arch/x86/net, branch linux-5.19.y

bpf: use bpf_prog_pack for bpf_dispatcher

2022-10-24T07:58:15Z

[ Upstream commit 19c02415da2345d0dda2b5c4495bc17cc14b18b5 ] Allocate bpf_dispatcher with bpf_prog_pack_alloc so that bpf_dispatcher can share pages with bpf programs. arch_prepare_bpf_dispatcher() is updated to provide a RW buffer as working area for arch code to write to. This also fixes CPA W^X warnning like: CPA refuse W^X violation: 8000000000000163 -> 0000000000000163 range: ... Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20220926184739.3512547-2-song@kernel.org Signed-off-by: Alexei Starovoitov Signed-off-by: Sasha Levin

bpf, x86: fix freeing of not-finalized bpf_prog_pack

2022-08-17T13:14:48Z

[ 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

2022-08-17T13:14:48Z

[ 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

x86/bpf: Use alternative RET encoding

2022-06-27T08:33:58Z

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

x86/retpoline: Cleanup some #ifdefery

2022-06-27T08:33:58Z

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

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

2022-06-16T19:48:24Z

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

bpf: Introduce bpf_arch_text_invalidate for bpf_prog_pack

2022-05-23T21:08:11Z

Introduce bpf_arch_text_invalidate and use it to fill unused part of the bpf_prog_pack with illegal instructions when a BPF program is freed. Fixes: 57631054fae6 ("bpf: Introduce bpf_prog_pack allocator") Fixes: 33c9805860e5 ("bpf: Introduce bpf_jit_binary_pack_[alloc|finalize|free]") Reported-by: Linus Torvalds Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220520235758.1858153-4-song@kernel.org

bpf, x86: Attach a cookie to fentry/fexit/fmod_ret/lsm.

2022-05-11T04:58:31Z

Pass a cookie along with BPF_LINK_CREATE requests. Add a bpf_cookie field to struct bpf_tracing_link to attach a cookie. The cookie of a bpf_tracing_link is available by calling bpf_get_attach_cookie when running the BPF program of the attached link. The value of a cookie will be set at bpf_tramp_run_ctx by the trampoline of the link. 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/20220510205923.3206889-4-kuifeng@fb.com

bpf, x86: Create bpf_tramp_run_ctx on the caller thread's stack

2022-05-11T00:50:51Z

BPF trampolines will create a bpf_tramp_run_ctx, a bpf_run_ctx, on stacks and set/reset the current bpf_run_ctx before/after calling a bpf_prog. 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/20220510205923.3206889-3-kuifeng@fb.com

bpf, x86: Generate trampolines from bpf_tramp_links

2022-05-11T00:50:40Z

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