This is a note to let you know that I've just added the patch titled powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: powerpc-bpf-fix-bpf_sub-when-imm-0x80000000.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Mon Nov 15 03:30:35 PM CET 2021 From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Date: Mon, 15 Nov 2021 16:35:08 +0530 Subject: powerpc/bpf: Fix BPF_SUB when imm == 0x80000000 To: <stable@xxxxxxxxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>, Daniel Borkmann <daniel@xxxxxxxxxxxxx> Message-ID: <5679896bb270f8a7bbbd5d2b2b7588a820231a21.1636968906.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx> From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> upstream commit 5855c4c1f415ca3ba1046e77c0b3d3dfc96c9025 We aren't handling subtraction involving an immediate value of 0x80000000 properly. Fix the same. Fixes: 156d0e290e969c ("powerpc/ebpf/jit: Implement JIT compiler for extended BPF") Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> [mpe: Fold in fix from Naveen to use imm <= 32768] Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/fc4b1276eb10761fd7ce0814c8dd089da2815251.1633464148.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx [adjust macros to account for commits 0654186510a40e and 3a181237916310] Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/net/bpf_jit_comp64.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -359,18 +359,25 @@ static int bpf_jit_build_body(struct bpf PPC_SUB(dst_reg, dst_reg, src_reg); goto bpf_alu32_trunc; case BPF_ALU | BPF_ADD | BPF_K: /* (u32) dst += (u32) imm */ - case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */ case BPF_ALU64 | BPF_ADD | BPF_K: /* dst += imm */ + if (!imm) { + goto bpf_alu32_trunc; + } else if (imm >= -32768 && imm < 32768) { + PPC_ADDI(dst_reg, dst_reg, IMM_L(imm)); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]); + } + goto bpf_alu32_trunc; + case BPF_ALU | BPF_SUB | BPF_K: /* (u32) dst -= (u32) imm */ case BPF_ALU64 | BPF_SUB | BPF_K: /* dst -= imm */ - if (BPF_OP(code) == BPF_SUB) - imm = -imm; - if (imm) { - if (imm >= -32768 && imm < 32768) - PPC_ADDI(dst_reg, dst_reg, IMM_L(imm)); - else { - PPC_LI32(b2p[TMP_REG_1], imm); - PPC_ADD(dst_reg, dst_reg, b2p[TMP_REG_1]); - } + if (!imm) { + goto bpf_alu32_trunc; + } else if (imm > -32768 && imm <= 32768) { + PPC_ADDI(dst_reg, dst_reg, IMM_L(-imm)); + } else { + PPC_LI32(b2p[TMP_REG_1], imm); + PPC_SUB(dst_reg, dst_reg, b2p[TMP_REG_1]); } goto bpf_alu32_trunc; case BPF_ALU | BPF_MUL | BPF_X: /* (u32) dst *= (u32) src */ Patches currently in stable-queue which might be from naveen.n.rao@xxxxxxxxxxxxxxxxxx are queue-4.14/powerpc-bpf-validate-branch-ranges.patch queue-4.14/powerpc-lib-add-helper-to-check-if-offset-is-within-conditional-branch-range.patch queue-4.14/powerpc-bpf-fix-bpf_sub-when-imm-0x80000000.patch