From 60b58afc96c9df71871df2dbad42037757ceef26 Mon Sep 17 00:00:00 2001 From: Alexei Starovoitov Date: Thu, 14 Dec 2017 17:55:14 -0800 Subject: bpf: fix net.core.bpf_jit_enable race global bpf_jit_enable variable is tested multiple times in JITs, blinding and verifier core. The malicious root can try to toggle it while loading the programs. This race condition was accounted for and there should be no issues, but it's safer to avoid this race condition. Signed-off-by: Alexei Starovoitov Acked-by: Daniel Borkmann Signed-off-by: Daniel Borkmann --- arch/sparc/net/bpf_jit_comp_64.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/sparc') diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c index 5765e7e711f7..a2f1b5e774a7 100644 --- a/arch/sparc/net/bpf_jit_comp_64.c +++ b/arch/sparc/net/bpf_jit_comp_64.c @@ -1517,7 +1517,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) u8 *image_ptr; int pass; - if (!bpf_jit_enable) + if (!prog->jit_requested) return orig_prog; tmp = bpf_jit_blind_constants(prog); -- cgit From 5f5a641116391f6c8c5fb4dad717895d2da96678 Mon Sep 17 00:00:00 2001 From: David Miller Date: Fri, 22 Dec 2017 09:42:41 -0500 Subject: bpf: sparc64: Add JIT support for multi-function programs. Modelled strongly upon the arm64 implementation. Signed-off-by: David S. Miller Signed-off-by: Daniel Borkmann --- arch/sparc/net/bpf_jit_comp_64.c | 44 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c index a2f1b5e774a7..991a3ab76e7a 100644 --- a/arch/sparc/net/bpf_jit_comp_64.c +++ b/arch/sparc/net/bpf_jit_comp_64.c @@ -1507,11 +1507,19 @@ static void jit_fill_hole(void *area, unsigned int size) *ptr++ = 0x91d02005; /* ta 5 */ } +struct sparc64_jit_data { + struct bpf_binary_header *header; + u8 *image; + struct jit_ctx ctx; +}; + struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) { struct bpf_prog *tmp, *orig_prog = prog; + struct sparc64_jit_data *jit_data; struct bpf_binary_header *header; bool tmp_blinded = false; + bool extra_pass = false; struct jit_ctx ctx; u32 image_size; u8 *image_ptr; @@ -1531,13 +1539,31 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) prog = tmp; } + jit_data = prog->aux->jit_data; + if (!jit_data) { + jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL); + if (!jit_data) { + prog = orig_prog; + goto out; + } + prog->aux->jit_data = jit_data; + } + if (jit_data->ctx.offset) { + ctx = jit_data->ctx; + image_ptr = jit_data->image; + header = jit_data->header; + extra_pass = true; + image_size = sizeof(u32) * ctx.idx; + goto skip_init_ctx; + } + memset(&ctx, 0, sizeof(ctx)); ctx.prog = prog; ctx.offset = kcalloc(prog->len, sizeof(unsigned int), GFP_KERNEL); if (ctx.offset == NULL) { prog = orig_prog; - goto out; + goto out_off; } /* Fake pass to detect features used, and get an accurate assessment @@ -1560,7 +1586,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) } ctx.image = (u32 *)image_ptr; - +skip_init_ctx: for (pass = 1; pass < 3; pass++) { ctx.idx = 0; @@ -1591,14 +1617,24 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) bpf_flush_icache(header, (u8 *)header + (header->pages * PAGE_SIZE)); - bpf_jit_binary_lock_ro(header); + if (!prog->is_func || extra_pass) { + bpf_jit_binary_lock_ro(header); + } else { + jit_data->ctx = ctx; + jit_data->image = image_ptr; + jit_data->header = header; + } prog->bpf_func = (void *)ctx.image; prog->jited = 1; prog->jited_len = image_size; + if (!prog->is_func || extra_pass) { out_off: - kfree(ctx.offset); + kfree(ctx.offset); + kfree(jit_data); + prog->aux->jit_data = NULL; + } out: if (tmp_blinded) bpf_jit_prog_release_other(prog, prog == orig_prog ? -- cgit From fa9dd599b4dae841924b022768354cfde9affecb Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 20 Jan 2018 01:24:33 +0100 Subject: bpf: get rid of pure_initcall dependency to enable jits 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 --- arch/sparc/net/bpf_jit_comp_32.c | 2 -- arch/sparc/net/bpf_jit_comp_64.c | 2 -- 2 files changed, 4 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/net/bpf_jit_comp_32.c b/arch/sparc/net/bpf_jit_comp_32.c index 09e318eb34ee..3bd8ca95e521 100644 --- a/arch/sparc/net/bpf_jit_comp_32.c +++ b/arch/sparc/net/bpf_jit_comp_32.c @@ -11,8 +11,6 @@ #include "bpf_jit_32.h" -int bpf_jit_enable __read_mostly; - static inline bool is_simm13(unsigned int value) { return value + 0x1000 < 0x2000; diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c index 635fdefd4ae2..50a24d7bd4c5 100644 --- a/arch/sparc/net/bpf_jit_comp_64.c +++ b/arch/sparc/net/bpf_jit_comp_64.c @@ -12,8 +12,6 @@ #include "bpf_jit_64.h" -int bpf_jit_enable __read_mostly; - static inline bool is_simm13(unsigned int value) { return value + 0x1000 < 0x2000; -- cgit From 740d52c646d748bf439ab3398359c3257efd022e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 26 Jan 2018 23:33:44 +0100 Subject: bpf, sparc64: remove obsolete exception handling from div/mod Since we've changed div/mod exception handling for src_reg in eBPF verifier itself, remove the leftovers from sparc64 JIT. Signed-off-by: Daniel Borkmann Cc: David S. Miller Signed-off-by: Alexei Starovoitov --- arch/sparc/net/bpf_jit_comp_64.c | 18 ------------------ 1 file changed, 18 deletions(-) (limited to 'arch/sparc') diff --git a/arch/sparc/net/bpf_jit_comp_64.c b/arch/sparc/net/bpf_jit_comp_64.c index 50a24d7bd4c5..48a25869349b 100644 --- a/arch/sparc/net/bpf_jit_comp_64.c +++ b/arch/sparc/net/bpf_jit_comp_64.c @@ -967,31 +967,17 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) emit_alu(MULX, src, dst, ctx); break; case BPF_ALU | BPF_DIV | BPF_X: - emit_cmp(src, G0, ctx); - emit_branch(BE|ANNUL, ctx->idx, ctx->epilogue_offset, ctx); - emit_loadimm(0, bpf2sparc[BPF_REG_0], ctx); - emit_write_y(G0, ctx); emit_alu(DIV, src, dst, ctx); break; - case BPF_ALU64 | BPF_DIV | BPF_X: - emit_cmp(src, G0, ctx); - emit_branch(BE|ANNUL, ctx->idx, ctx->epilogue_offset, ctx); - emit_loadimm(0, bpf2sparc[BPF_REG_0], ctx); - emit_alu(UDIVX, src, dst, ctx); break; - case BPF_ALU | BPF_MOD | BPF_X: { const u8 tmp = bpf2sparc[TMP_REG_1]; ctx->tmp_1_used = true; - emit_cmp(src, G0, ctx); - emit_branch(BE|ANNUL, ctx->idx, ctx->epilogue_offset, ctx); - emit_loadimm(0, bpf2sparc[BPF_REG_0], ctx); - emit_write_y(G0, ctx); emit_alu3(DIV, dst, src, tmp, ctx); emit_alu3(MULX, tmp, src, tmp, ctx); @@ -1003,10 +989,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) ctx->tmp_1_used = true; - emit_cmp(src, G0, ctx); - emit_branch(BE|ANNUL, ctx->idx, ctx->epilogue_offset, ctx); - emit_loadimm(0, bpf2sparc[BPF_REG_0], ctx); - emit_alu3(UDIVX, dst, src, tmp, ctx); emit_alu3(MULX, tmp, src, tmp, ctx); emit_alu3(SUB, dst, tmp, dst, ctx); -- cgit