diff options
| -rw-r--r-- | arch/arm/net/bpf_jit_32.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/arch/arm/net/bpf_jit_32.c b/arch/arm/net/bpf_jit_32.c index f412b53ed268..e0e23582c8b4 100644 --- a/arch/arm/net/bpf_jit_32.c +++ b/arch/arm/net/bpf_jit_32.c @@ -54,6 +54,7 @@ #define SEEN_DATA (1 << (BPF_MEMWORDS + 3)) #define FLAG_NEED_X_RESET (1 << 0) +#define FLAG_IMM_OVERFLOW (1 << 1) struct jit_ctx { const struct bpf_prog *skf; @@ -293,6 +294,15 @@ static u16 imm_offset(u32 k, struct jit_ctx *ctx) /* PC in ARM mode == address of the instruction + 8 */ imm = offset - (8 + ctx->idx * 4); + if (imm & ~0xfff) { + /* + * literal pool is too far, signal it into flags. we + * can only detect it on the second pass unfortunately. + */ + ctx->flags |= FLAG_IMM_OVERFLOW; + return 0; + } + return imm; } @@ -866,6 +876,14 @@ b_epilogue: default: return -1; } + + if (ctx->flags & FLAG_IMM_OVERFLOW) + /* + * this instruction generated an overflow when + * trying to access the literal pool, so + * delegate this filter to the kernel interpreter. + */ + return -1; } /* compute offsets only during the first pass */ @@ -928,7 +946,14 @@ void bpf_jit_compile(struct bpf_prog *fp) ctx.idx = 0; build_prologue(&ctx); - build_body(&ctx); + if (build_body(&ctx) < 0) { +#if __LINUX_ARM_ARCH__ < 7 + if (ctx.imm_count) + kfree(ctx.imms); +#endif + bpf_jit_binary_free(header); + goto out; + } build_epilogue(&ctx); flush_icache_range((u32)ctx.target, (u32)(ctx.target + ctx.idx)); |