From: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxxxxxxx> upstream commit 3832ba4e283d7052b783dab8311df7e3590fed93 Add checks to ensure that we never emit branch instructions with truncated branch offsets. Suggested-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Tested-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx> Reviewed-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx> Acked-by: Song Liu <songliubraving@xxxxxx> Acked-by: Johan Almbladh <johan.almbladh@xxxxxxxxxxxxxxxxx> Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/71d33a6b7603ec1013c9734dd8bdd4ff5e929142.1633464148.git.naveen.n.rao@xxxxxxxxxxxxxxxxxx [include header, drop ppc32 changes] Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/powerpc/net/bpf_jit.h | 26 ++++++++++++++++++++------ arch/powerpc/net/bpf_jit_comp64.c | 8 ++++++-- 2 files changed, 26 insertions(+), 8 deletions(-) --- a/arch/powerpc/net/bpf_jit.h +++ b/arch/powerpc/net/bpf_jit.h @@ -11,6 +11,7 @@ #ifndef __ASSEMBLY__ #include <asm/types.h> +#include <asm/code-patching.h> #ifdef PPC64_ELF_ABI_v1 #define FUNCTION_DESCR_SIZE 24 @@ -180,13 +181,26 @@ #define PPC_NEG(d, a) EMIT(PPC_INST_NEG | ___PPC_RT(d) | ___PPC_RA(a)) /* Long jump; (unconditional 'branch') */ -#define PPC_JMP(dest) EMIT(PPC_INST_BRANCH | \ - (((dest) - (ctx->idx * 4)) & 0x03fffffc)) +#define PPC_JMP(dest) \ + do { \ + long offset = (long)(dest) - (ctx->idx * 4); \ + if (!is_offset_in_branch_range(offset)) { \ + pr_err_ratelimited("Branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_INST_BRANCH | (offset & 0x03fffffc)); \ + } while (0) /* "cond" here covers BO:BI fields. */ -#define PPC_BCC_SHORT(cond, dest) EMIT(PPC_INST_BRANCH_COND | \ - (((cond) & 0x3ff) << 16) | \ - (((dest) - (ctx->idx * 4)) & \ - 0xfffc)) +#define PPC_BCC_SHORT(cond, dest) \ + do { \ + long offset = (long)(dest) - (ctx->idx * 4); \ + if (!is_offset_in_cond_branch_range(offset)) { \ + pr_err_ratelimited("Conditional branch offset 0x%lx (@%u) out of range\n", offset, ctx->idx); \ + return -ERANGE; \ + } \ + EMIT(PPC_INST_BRANCH_COND | (((cond) & 0x3ff) << 16) | (offset & 0xfffc)); \ + } while (0) + /* Sign-extended 32-bit immediate load */ #define PPC_LI32(d, i) do { \ if ((int)(uintptr_t)(i) >= -32768 && \ --- a/arch/powerpc/net/bpf_jit_comp64.c +++ b/arch/powerpc/net/bpf_jit_comp64.c @@ -224,7 +224,7 @@ static void bpf_jit_emit_func_call_rel(u PPC_BLRL(); } -static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) +static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 out) { /* * By now, the eBPF program has already setup parameters in r3, r4 and r5 @@ -285,7 +285,9 @@ static void bpf_jit_emit_tail_call(u32 * bpf_jit_emit_common_epilogue(image, ctx); PPC_BCTR(); + /* out: */ + return 0; } /* Assemble the body code between the prologue & epilogue */ @@ -1001,7 +1003,9 @@ cond_branch: */ case BPF_JMP | BPF_TAIL_CALL: ctx->seen |= SEEN_TAILCALL; - bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); + ret = bpf_jit_emit_tail_call(image, ctx, addrs[i + 1]); + if (ret < 0) + return ret; break; default:
