diff options
Diffstat (limited to 'kernel/bpf')
-rw-r--r-- | kernel/bpf/arena.c | 25 | ||||
-rw-r--r-- | kernel/bpf/verifier.c | 22 |
2 files changed, 37 insertions, 10 deletions
diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c index 86571e760dd6..343c3456c8dd 100644 --- a/kernel/bpf/arena.c +++ b/kernel/bpf/arena.c @@ -38,7 +38,7 @@ /* number of bytes addressable by LDX/STX insn with 16-bit 'off' field */ #define GUARD_SZ (1ull << sizeof(((struct bpf_insn *)0)->off) * 8) -#define KERN_VM_SZ ((1ull << 32) + GUARD_SZ) +#define KERN_VM_SZ (SZ_4G + GUARD_SZ) struct bpf_arena { struct bpf_map map; @@ -110,7 +110,7 @@ static struct bpf_map *arena_map_alloc(union bpf_attr *attr) return ERR_PTR(-EINVAL); vm_range = (u64)attr->max_entries * PAGE_SIZE; - if (vm_range > (1ull << 32)) + if (vm_range > SZ_4G) return ERR_PTR(-E2BIG); if ((attr->map_extra >> 32) != ((attr->map_extra + vm_range - 1) >> 32)) @@ -301,7 +301,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad if (pgoff) return -EINVAL; - if (len > (1ull << 32)) + if (len > SZ_4G) return -E2BIG; /* if user_vm_start was specified at arena creation time */ @@ -322,7 +322,7 @@ static unsigned long arena_get_unmapped_area(struct file *filp, unsigned long ad if (WARN_ON_ONCE(arena->user_vm_start)) /* checks at map creation time should prevent this */ return -EFAULT; - return round_up(ret, 1ull << 32); + return round_up(ret, SZ_4G); } static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) @@ -346,7 +346,7 @@ static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) return -EBUSY; /* Earlier checks should prevent this */ - if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > (1ull << 32) || vma->vm_pgoff)) + if (WARN_ON_ONCE(vma->vm_end - vma->vm_start > SZ_4G || vma->vm_pgoff)) return -EFAULT; if (remember_vma(arena, vma)) @@ -420,7 +420,7 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt if (uaddr & ~PAGE_MASK) return 0; pgoff = compute_pgoff(arena, uaddr); - if (pgoff + page_cnt > page_cnt_max) + if (pgoff > page_cnt_max - page_cnt) /* requested address will be outside of user VMA */ return 0; } @@ -447,7 +447,13 @@ static long arena_alloc_pages(struct bpf_arena *arena, long uaddr, long page_cnt goto out; uaddr32 = (u32)(arena->user_vm_start + pgoff * PAGE_SIZE); - /* Earlier checks make sure that uaddr32 + page_cnt * PAGE_SIZE will not overflow 32-bit */ + /* Earlier checks made sure that uaddr32 + page_cnt * PAGE_SIZE - 1 + * will not overflow 32-bit. Lower 32-bit need to represent + * contiguous user address range. + * Map these pages at kern_vm_start base. + * kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE - 1 can overflow + * lower 32-bit and it's ok. + */ ret = vm_area_map_pages(arena->kern_vm, kern_vm_start + uaddr32, kern_vm_start + uaddr32 + page_cnt * PAGE_SIZE, pages); if (ret) { @@ -510,6 +516,11 @@ static void arena_free_pages(struct bpf_arena *arena, long uaddr, long page_cnt) if (!page) continue; if (page_cnt == 1 && page_mapped(page)) /* mapped by some user process */ + /* Optimization for the common case of page_cnt==1: + * If page wasn't mapped into some user vma there + * is no need to call zap_pages which is slow. When + * page_cnt is big it's faster to do the batched zap. + */ zap_pages(arena, full_uaddr, 1); vm_area_unmap_pages(arena->kern_vm, kaddr, kaddr + PAGE_SIZE); __free_page(page); diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 63749ad5ac6b..0bfc0050db28 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -5682,6 +5682,13 @@ static bool is_flow_key_reg(struct bpf_verifier_env *env, int regno) return reg->type == PTR_TO_FLOW_KEYS; } +static bool is_arena_reg(struct bpf_verifier_env *env, int regno) +{ + const struct bpf_reg_state *reg = reg_state(env, regno); + + return reg->type == PTR_TO_ARENA; +} + static u32 *reg2btf_ids[__BPF_REG_TYPE_MAX] = { #ifdef CONFIG_NET [PTR_TO_SOCKET] = &btf_sock_ids[BTF_SOCK_TYPE_SOCK], @@ -7019,7 +7026,8 @@ static int check_atomic(struct bpf_verifier_env *env, int insn_idx, struct bpf_i if (is_ctx_reg(env, insn->dst_reg) || is_pkt_reg(env, insn->dst_reg) || is_flow_key_reg(env, insn->dst_reg) || - is_sk_reg(env, insn->dst_reg)) { + is_sk_reg(env, insn->dst_reg) || + is_arena_reg(env, insn->dst_reg)) { verbose(env, "BPF_ATOMIC stores into R%d %s is not allowed\n", insn->dst_reg, reg_type_str(env, reg_state(env, insn->dst_reg)->type)); @@ -14014,6 +14022,10 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) verbose(env, "addr_space_cast insn can only convert between address space 1 and 0\n"); return -EINVAL; } + if (!env->prog->aux->arena) { + verbose(env, "addr_space_cast insn can only be used in a program that has an associated arena\n"); + return -EINVAL; + } } else { if ((insn->off != 0 && insn->off != 8 && insn->off != 16 && insn->off != 32) || insn->imm) { @@ -14046,8 +14058,11 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn) if (insn->imm) { /* off == BPF_ADDR_SPACE_CAST */ mark_reg_unknown(env, regs, insn->dst_reg); - if (insn->imm == 1) /* cast from as(1) to as(0) */ + if (insn->imm == 1) { /* cast from as(1) to as(0) */ dst_reg->type = PTR_TO_ARENA; + /* PTR_TO_ARENA is 32-bit */ + dst_reg->subreg_def = env->insn_idx + 1; + } } else if (insn->off == 0) { /* case: R1 = R2 * copy register state to dest reg @@ -19601,8 +19616,9 @@ static int do_misc_fixups(struct bpf_verifier_env *env) (((struct bpf_map *)env->prog->aux->arena)->map_flags & BPF_F_NO_USER_CONV)) { /* convert to 32-bit mov that clears upper 32-bit */ insn->code = BPF_ALU | BPF_MOV | BPF_X; - /* clear off, so it's a normal 'wX = wY' from JIT pov */ + /* clear off and imm, so it's a normal 'wX = wY' from JIT pov */ insn->off = 0; + insn->imm = 0; } /* cast from as(0) to as(1) should be handled by JIT */ goto next_insn; } |