Re: [RFC PATCH 07/11] bpf: implement writable buffers in contexts

From: Steven Rostedt
Date: Mon May 20 2019 - 21:24:08 EST


Hi Kris,

Note, it's best to thread patches. Otherwise they get spread out in
mail boxes and hard to manage. That is, every patch should be a reply
to the 00/11 header patch.

Also, Peter Ziljstra (Cc'd) is the maintainer of perf on the kernel
side. Please include him on Ccing perf changes that are done inside the
kernel.

-- Steve


On Mon, 20 May 2019 23:52:24 +0000 (UTC)
Kris Van Hees <kris.van.hees@xxxxxxxxxx> wrote:

> Currently, BPF supports writes to packet data in very specific cases.
> The implementation can be of more general use and can be extended to any
> number of writable buffers in a context. The implementation adds two new
> register types: PTR_TO_BUFFER and PTR_TO_BUFFER_END, similar to the types
> PTR_TO_PACKET and PTR_TO_PACKET_END. In addition, a field 'buf_id' is
> added to the reg_state structure as a way to distinguish between different
> buffers in a single context.
>
> Buffers are specified in the context by a pair of members:
> - a pointer to the start of the buffer (type PTR_TO_BUFFER)
> - a pointer to the first byte beyond the buffer (type PTR_TO_BUFFER_END)
>
> A context can contain multiple buffers. Each buffer/buffer_end pair is
> identified by a unique id (buf_id). The start-of-buffer member offset is
> usually a good unique identifier.
>
> The semantics for using a writable buffer are the same as for packet data.
> The BPF program must contain a range test (buf + num > buf_end) to ensure
> that the verifier can verify that offsets are within the allowed range.
>
> Whenever a helper is called that might update the content of the context
> all range information for registers that hold pointers to a buffer is
> cleared, just as it is done for packet pointers.
>
> Signed-off-by: Kris Van Hees <kris.van.hees@xxxxxxxxxx>
> Reviewed-by: Nick Alcock <nick.alcock@xxxxxxxxxx>
> ---
> include/linux/bpf.h | 3 +
> include/linux/bpf_verifier.h | 4 +-
> kernel/bpf/verifier.c | 198 ++++++++++++++++++++++++-----------
> 3 files changed, 145 insertions(+), 60 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index e4bcb79656c4..fc3eda0192fb 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -275,6 +275,8 @@ enum bpf_reg_type {
> PTR_TO_TCP_SOCK, /* reg points to struct tcp_sock */
> PTR_TO_TCP_SOCK_OR_NULL, /* reg points to struct tcp_sock or NULL */
> PTR_TO_TP_BUFFER, /* reg points to a writable raw tp's buffer */
> + PTR_TO_BUFFER, /* reg points to ctx buffer */
> + PTR_TO_BUFFER_END, /* reg points to ctx buffer end */
> };
>
> /* The information passed from prog-specific *_is_valid_access
> @@ -283,6 +285,7 @@ enum bpf_reg_type {
> struct bpf_insn_access_aux {
> enum bpf_reg_type reg_type;
> int ctx_field_size;
> + u32 buf_id;
> };
>
> static inline void
> diff --git a/include/linux/bpf_verifier.h b/include/linux/bpf_verifier.h
> index 1305ccbd8fe6..3538382184f3 100644
> --- a/include/linux/bpf_verifier.h
> +++ b/include/linux/bpf_verifier.h
> @@ -45,7 +45,7 @@ struct bpf_reg_state {
> /* Ordering of fields matters. See states_equal() */
> enum bpf_reg_type type;
> union {
> - /* valid when type == PTR_TO_PACKET */
> + /* valid when type == PTR_TO_PACKET | PTR_TO_BUFFER */
> u16 range;
>
> /* valid when type == CONST_PTR_TO_MAP | PTR_TO_MAP_VALUE |
> @@ -132,6 +132,8 @@ struct bpf_reg_state {
> */
> u32 frameno;
> enum bpf_reg_liveness live;
> + /* For PTR_TO_BUFFER, to identify distinct buffers in a context. */
> + u32 buf_id;
> };
>
> enum bpf_stack_slot_type {
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index f9e5536fd1af..5fba4e6f5424 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -406,6 +406,8 @@ static const char * const reg_type_str[] = {
> [PTR_TO_TCP_SOCK] = "tcp_sock",
> [PTR_TO_TCP_SOCK_OR_NULL] = "tcp_sock_or_null",
> [PTR_TO_TP_BUFFER] = "tp_buffer",
> + [PTR_TO_BUFFER] = "buf",
> + [PTR_TO_BUFFER_END] = "buf_end",
> };
>
> static char slot_type_char[] = {
> @@ -467,6 +469,9 @@ static void print_verifier_state(struct bpf_verifier_env *env,
> verbose(env, ",off=%d", reg->off);
> if (type_is_pkt_pointer(t))
> verbose(env, ",r=%d", reg->range);
> + else if (t == PTR_TO_BUFFER)
> + verbose(env, ",r=%d,bid=%d", reg->range,
> + reg->buf_id);
> else if (t == CONST_PTR_TO_MAP ||
> t == PTR_TO_MAP_VALUE ||
> t == PTR_TO_MAP_VALUE_OR_NULL)
> @@ -855,6 +860,12 @@ static bool reg_is_pkt_pointer_any(const struct bpf_reg_state *reg)
> reg->type == PTR_TO_PACKET_END;
> }
>
> +static bool reg_is_buf_pointer_any(const struct bpf_reg_state *reg)
> +{
> + return reg_is_pkt_pointer_any(reg) ||
> + reg->type == PTR_TO_BUFFER || reg->type == PTR_TO_BUFFER_END;
> +}
> +
> /* Unmodified PTR_TO_PACKET[_META,_END] register from ctx access. */
> static bool reg_is_init_pkt_pointer(const struct bpf_reg_state *reg,
> enum bpf_reg_type which)
> @@ -1550,7 +1561,7 @@ static int check_map_access(struct bpf_verifier_env *env, u32 regno,
> return err;
> }
>
> -#define MAX_PACKET_OFF 0xffff
> +#define MAX_BUFFER_OFF 0xffff
>
> static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
> const struct bpf_call_arg_meta *meta,
> @@ -1585,7 +1596,7 @@ static bool may_access_direct_pkt_data(struct bpf_verifier_env *env,
> }
> }
>
> -static int __check_packet_access(struct bpf_verifier_env *env, u32 regno,
> +static int __check_buffer_access(struct bpf_verifier_env *env, u32 regno,
> int off, int size, bool zero_size_allowed)
> {
> struct bpf_reg_state *regs = cur_regs(env);
> @@ -1593,14 +1604,15 @@ static int __check_packet_access(struct bpf_verifier_env *env, u32 regno,
>
> if (off < 0 || size < 0 || (size == 0 && !zero_size_allowed) ||
> (u64)off + size > reg->range) {
> - verbose(env, "invalid access to packet, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
> - off, size, regno, reg->id, reg->off, reg->range);
> + verbose(env, "invalid access to %s, off=%d size=%d, R%d(id=%d,off=%d,r=%d)\n",
> + reg_is_pkt_pointer(reg) ? "packet" : "buffer", off,
> + size, regno, reg->id, reg->off, reg->range);
> return -EACCES;
> }
> return 0;
> }
>
> -static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
> +static int check_buffer_access(struct bpf_verifier_env *env, u32 regno, int off,
> int size, bool zero_size_allowed)
> {
> struct bpf_reg_state *regs = cur_regs(env);
> @@ -1620,35 +1632,37 @@ static int check_packet_access(struct bpf_verifier_env *env, u32 regno, int off,
> regno);
> return -EACCES;
> }
> - err = __check_packet_access(env, regno, off, size, zero_size_allowed);
> + err = __check_buffer_access(env, regno, off, size, zero_size_allowed);
> if (err) {
> - verbose(env, "R%d offset is outside of the packet\n", regno);
> + verbose(env, "R%d offset is outside of the %s\n",
> + regno, reg_is_pkt_pointer(reg) ? "packet" : "buffer");
> return err;
> }
>
> - /* __check_packet_access has made sure "off + size - 1" is within u16.
> - * reg->umax_value can't be bigger than MAX_PACKET_OFF which is 0xffff,
> - * otherwise find_good_pkt_pointers would have refused to set range info
> - * that __check_packet_access would have rejected this pkt access.
> - * Therefore, "off + reg->umax_value + size - 1" won't overflow u32.
> - */
> - env->prog->aux->max_pkt_offset =
> - max_t(u32, env->prog->aux->max_pkt_offset,
> - off + reg->umax_value + size - 1);
> + if (reg_is_pkt_pointer(reg)) {
> + /* __check_buffer_access ensures "off + size - 1" is within u16
> + * reg->umax_value can't be bigger than * MAX_BUFFER_OFF which
> + * is 0xffff, otherwise find_good_buf_pointers would have
> + * refused to set range info and __check_buffer_access would
> + * have rejected this pkt access.
> + * Therefore, "off + reg->umax_value + size - 1" won't overflow
> + * u32.
> + */
> + env->prog->aux->max_pkt_offset =
> + max_t(u32, env->prog->aux->max_pkt_offset,
> + off + reg->umax_value + size - 1);
> + }
>
> return err;
> }
>
> /* check access to 'struct bpf_context' fields. Supports fixed offsets only */
> -static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off, int size,
> - enum bpf_access_type t, enum bpf_reg_type *reg_type)
> +static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx,
> + int off, int size, enum bpf_access_type t,
> + struct bpf_insn_access_aux *info)
> {
> - struct bpf_insn_access_aux info = {
> - .reg_type = *reg_type,
> - };
> -
> if (env->ops->is_valid_access &&
> - env->ops->is_valid_access(off, size, t, env->prog, &info)) {
> + env->ops->is_valid_access(off, size, t, env->prog, info)) {
> /* A non zero info.ctx_field_size indicates that this field is a
> * candidate for later verifier transformation to load the whole
> * field and then apply a mask when accessed with a narrower
> @@ -1656,9 +1670,7 @@ static int check_ctx_access(struct bpf_verifier_env *env, int insn_idx, int off,
> * will only allow for whole field access and rejects any other
> * type of narrower access.
> */
> - *reg_type = info.reg_type;
> -
> - env->insn_aux_data[insn_idx].ctx_field_size = info.ctx_field_size;
> + env->insn_aux_data[insn_idx].ctx_field_size = info->ctx_field_size;
> /* remember the offset of last byte accessed in ctx */
> if (env->prog->aux->max_ctx_offset < off + size)
> env->prog->aux->max_ctx_offset = off + size;
> @@ -1870,6 +1882,10 @@ static int check_ptr_alignment(struct bpf_verifier_env *env,
> case PTR_TO_TCP_SOCK:
> pointer_desc = "tcp_sock ";
> break;
> + case PTR_TO_BUFFER:
> + pointer_desc = "buffer ";
> + strict = true;
> + break;
> default:
> break;
> }
> @@ -2084,7 +2100,11 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
> mark_reg_unknown(env, regs, value_regno);
>
> } else if (reg->type == PTR_TO_CTX) {
> - enum bpf_reg_type reg_type = SCALAR_VALUE;
> + struct bpf_insn_access_aux info = {
> + .reg_type = SCALAR_VALUE,
> + .buf_id = 0,
> + };
> +
>
> if (t == BPF_WRITE && value_regno >= 0 &&
> is_pointer_value(env, value_regno)) {
> @@ -2096,21 +2116,22 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
> if (err < 0)
> return err;
>
> - err = check_ctx_access(env, insn_idx, off, size, t, &reg_type);
> + err = check_ctx_access(env, insn_idx, off, size, t, &info);
> if (!err && t == BPF_READ && value_regno >= 0) {
> /* ctx access returns either a scalar, or a
> * PTR_TO_PACKET[_META,_END]. In the latter
> * case, we know the offset is zero.
> */
> - if (reg_type == SCALAR_VALUE) {
> + if (info.reg_type == SCALAR_VALUE) {
> mark_reg_unknown(env, regs, value_regno);
> } else {
> mark_reg_known_zero(env, regs,
> value_regno);
> - if (reg_type_may_be_null(reg_type))
> + if (reg_type_may_be_null(info.reg_type))
> regs[value_regno].id = ++env->id_gen;
> }
> - regs[value_regno].type = reg_type;
> + regs[value_regno].type = info.reg_type;
> + regs[value_regno].buf_id = info.buf_id;
> }
>
> } else if (reg->type == PTR_TO_STACK) {
> @@ -2141,7 +2162,17 @@ static int check_mem_access(struct bpf_verifier_env *env, int insn_idx, u32 regn
> value_regno);
> return -EACCES;
> }
> - err = check_packet_access(env, regno, off, size, false);
> + err = check_buffer_access(env, regno, off, size, false);
> + if (!err && t == BPF_READ && value_regno >= 0)
> + mark_reg_unknown(env, regs, value_regno);
> + } else if (reg->type == PTR_TO_BUFFER) {
> + if (t == BPF_WRITE && value_regno >= 0 &&
> + is_pointer_value(env, value_regno)) {
> + verbose(env, "R%d leaks addr into buffer\n",
> + value_regno);
> + return -EACCES;
> + }
> + err = check_buffer_access(env, regno, off, size, false);
> if (!err && t == BPF_READ && value_regno >= 0)
> mark_reg_unknown(env, regs, value_regno);
> } else if (reg->type == PTR_TO_FLOW_KEYS) {
> @@ -2382,7 +2413,7 @@ static int check_helper_mem_access(struct bpf_verifier_env *env, int regno,
> switch (reg->type) {
> case PTR_TO_PACKET:
> case PTR_TO_PACKET_META:
> - return check_packet_access(env, regno, reg->off, access_size,
> + return check_buffer_access(env, regno, reg->off, access_size,
> zero_size_allowed);
> case PTR_TO_MAP_VALUE:
> if (check_map_access_type(env, regno, reg->off, access_size,
> @@ -2962,34 +2993,35 @@ static int check_func_proto(const struct bpf_func_proto *fn, int func_id)
> check_refcount_ok(fn, func_id) ? 0 : -EINVAL;
> }
>
> -/* Packet data might have moved, any old PTR_TO_PACKET[_META,_END]
> - * are now invalid, so turn them into unknown SCALAR_VALUE.
> +/* Packet or buffer data might have moved, any old PTR_TO_PACKET[_META,_END]
> + * and/or PTR_TO_BUFFER[_END] are now invalid, so turn them into unknown
> + * SCALAR_VALUE.
> */
> -static void __clear_all_pkt_pointers(struct bpf_verifier_env *env,
> +static void __clear_all_buf_pointers(struct bpf_verifier_env *env,
> struct bpf_func_state *state)
> {
> struct bpf_reg_state *regs = state->regs, *reg;
> int i;
>
> for (i = 0; i < MAX_BPF_REG; i++)
> - if (reg_is_pkt_pointer_any(&regs[i]))
> + if (reg_is_buf_pointer_any(&regs[i]))
> mark_reg_unknown(env, regs, i);
>
> bpf_for_each_spilled_reg(i, state, reg) {
> if (!reg)
> continue;
> - if (reg_is_pkt_pointer_any(reg))
> + if (reg_is_buf_pointer_any(reg))
> __mark_reg_unknown(reg);
> }
> }
>
> -static void clear_all_pkt_pointers(struct bpf_verifier_env *env)
> +static void clear_all_buf_pointers(struct bpf_verifier_env *env)
> {
> struct bpf_verifier_state *vstate = env->cur_state;
> int i;
>
> for (i = 0; i <= vstate->curframe; i++)
> - __clear_all_pkt_pointers(env, vstate->frame[i]);
> + __clear_all_buf_pointers(env, vstate->frame[i]);
> }
>
> static void release_reg_references(struct bpf_verifier_env *env,
> @@ -3417,7 +3449,7 @@ static int check_helper_call(struct bpf_verifier_env *env, int func_id, int insn
> }
>
> if (changes_data)
> - clear_all_pkt_pointers(env);
> + clear_all_buf_pointers(env);
> return 0;
> }
>
> @@ -4349,7 +4381,7 @@ static int check_alu_op(struct bpf_verifier_env *env, struct bpf_insn *insn)
> return 0;
> }
>
> -static void __find_good_pkt_pointers(struct bpf_func_state *state,
> +static void __find_good_buf_pointers(struct bpf_func_state *state,
> struct bpf_reg_state *dst_reg,
> enum bpf_reg_type type, u16 new_range)
> {
> @@ -4358,7 +4390,11 @@ static void __find_good_pkt_pointers(struct bpf_func_state *state,
>
> for (i = 0; i < MAX_BPF_REG; i++) {
> reg = &state->regs[i];
> - if (reg->type == type && reg->id == dst_reg->id)
> + if (reg->type != type)
> + continue;
> + if (type == PTR_TO_BUFFER && reg->buf_id != dst_reg->buf_id)
> + continue;
> + if (reg->id == dst_reg->id)
> /* keep the maximum range already checked */
> reg->range = max(reg->range, new_range);
> }
> @@ -4366,12 +4402,16 @@ static void __find_good_pkt_pointers(struct bpf_func_state *state,
> bpf_for_each_spilled_reg(i, state, reg) {
> if (!reg)
> continue;
> - if (reg->type == type && reg->id == dst_reg->id)
> + if (reg->type != type)
> + continue;
> + if (type == PTR_TO_BUFFER && reg->buf_id != dst_reg->buf_id)
> + continue;
> + if (reg->id == dst_reg->id)
> reg->range = max(reg->range, new_range);
> }
> }
>
> -static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
> +static void find_good_buf_pointers(struct bpf_verifier_state *vstate,
> struct bpf_reg_state *dst_reg,
> enum bpf_reg_type type,
> bool range_right_open)
> @@ -4384,8 +4424,8 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
> /* This doesn't give us any range */
> return;
>
> - if (dst_reg->umax_value > MAX_PACKET_OFF ||
> - dst_reg->umax_value + dst_reg->off > MAX_PACKET_OFF)
> + if (dst_reg->umax_value > MAX_BUFFER_OFF ||
> + dst_reg->umax_value + dst_reg->off > MAX_BUFFER_OFF)
> /* Risk of overflow. For instance, ptr + (1<<63) may be less
> * than pkt_end, but that's because it's also less than pkt.
> */
> @@ -4440,10 +4480,10 @@ static void find_good_pkt_pointers(struct bpf_verifier_state *vstate,
> /* If our ids match, then we must have the same max_value. And we
> * don't care about the other reg's fixed offset, since if it's too big
> * the range won't allow anything.
> - * dst_reg->off is known < MAX_PACKET_OFF, therefore it fits in a u16.
> + * dst_reg->off is known < MAX_BUFFER_OFF, therefore it fits in a u16.
> */
> for (i = 0; i <= vstate->curframe; i++)
> - __find_good_pkt_pointers(vstate->frame[i], dst_reg, type,
> + __find_good_buf_pointers(vstate->frame[i], dst_reg, type,
> new_range);
> }
>
> @@ -4934,7 +4974,7 @@ static void __mark_ptr_or_null_regs(struct bpf_func_state *state, u32 id,
> }
> }
>
> -/* The logic is similar to find_good_pkt_pointers(), both could eventually
> +/* The logic is similar to find_good_buf_pointers(), both could eventually
> * be folded together at some point.
> */
> static void mark_ptr_or_null_regs(struct bpf_verifier_state *vstate, u32 regno,
> @@ -4977,14 +5017,24 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn,
> (dst_reg->type == PTR_TO_PACKET_META &&
> reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
> /* pkt_data' > pkt_end, pkt_meta' > pkt_data */
> - find_good_pkt_pointers(this_branch, dst_reg,
> + find_good_buf_pointers(this_branch, dst_reg,
> dst_reg->type, false);
> } else if ((dst_reg->type == PTR_TO_PACKET_END &&
> src_reg->type == PTR_TO_PACKET) ||
> (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
> src_reg->type == PTR_TO_PACKET_META)) {
> /* pkt_end > pkt_data', pkt_data > pkt_meta' */
> - find_good_pkt_pointers(other_branch, src_reg,
> + find_good_buf_pointers(other_branch, src_reg,
> + src_reg->type, true);
> + } else if (dst_reg->type == PTR_TO_BUFFER &&
> + src_reg->type == PTR_TO_BUFFER_END) {
> + /* buf' > buf_end */
> + find_good_buf_pointers(this_branch, dst_reg,
> + dst_reg->type, false);
> + } else if (dst_reg->type == PTR_TO_BUFFER_END &&
> + src_reg->type == PTR_TO_BUFFER) {
> + /* buf_end > buf' */
> + find_good_buf_pointers(other_branch, src_reg,
> src_reg->type, true);
> } else {
> return false;
> @@ -4996,14 +5046,24 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn,
> (dst_reg->type == PTR_TO_PACKET_META &&
> reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
> /* pkt_data' < pkt_end, pkt_meta' < pkt_data */
> - find_good_pkt_pointers(other_branch, dst_reg,
> + find_good_buf_pointers(other_branch, dst_reg,
> dst_reg->type, true);
> } else if ((dst_reg->type == PTR_TO_PACKET_END &&
> src_reg->type == PTR_TO_PACKET) ||
> (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
> src_reg->type == PTR_TO_PACKET_META)) {
> /* pkt_end < pkt_data', pkt_data > pkt_meta' */
> - find_good_pkt_pointers(this_branch, src_reg,
> + find_good_buf_pointers(this_branch, src_reg,
> + src_reg->type, false);
> + } else if (dst_reg->type == PTR_TO_BUFFER &&
> + src_reg->type == PTR_TO_BUFFER_END) {
> + /* buf' < buf_end */
> + find_good_buf_pointers(other_branch, dst_reg,
> + dst_reg->type, true);
> + } else if (dst_reg->type == PTR_TO_BUFFER_END &&
> + src_reg->type == PTR_TO_BUFFER) {
> + /* buf_end < buf' */
> + find_good_buf_pointers(this_branch, src_reg,
> src_reg->type, false);
> } else {
> return false;
> @@ -5015,14 +5075,24 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn,
> (dst_reg->type == PTR_TO_PACKET_META &&
> reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
> /* pkt_data' >= pkt_end, pkt_meta' >= pkt_data */
> - find_good_pkt_pointers(this_branch, dst_reg,
> + find_good_buf_pointers(this_branch, dst_reg,
> dst_reg->type, true);
> } else if ((dst_reg->type == PTR_TO_PACKET_END &&
> src_reg->type == PTR_TO_PACKET) ||
> (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
> src_reg->type == PTR_TO_PACKET_META)) {
> /* pkt_end >= pkt_data', pkt_data >= pkt_meta' */
> - find_good_pkt_pointers(other_branch, src_reg,
> + find_good_buf_pointers(other_branch, src_reg,
> + src_reg->type, false);
> + } else if (dst_reg->type == PTR_TO_BUFFER &&
> + src_reg->type == PTR_TO_BUFFER_END) {
> + /* buf' >= buf_end */
> + find_good_buf_pointers(this_branch, dst_reg,
> + dst_reg->type, true);
> + } else if (dst_reg->type == PTR_TO_BUFFER_END &&
> + src_reg->type == PTR_TO_BUFFER) {
> + /* buf_end >= buf' */
> + find_good_buf_pointers(other_branch, src_reg,
> src_reg->type, false);
> } else {
> return false;
> @@ -5034,15 +5104,25 @@ static bool try_match_pkt_pointers(const struct bpf_insn *insn,
> (dst_reg->type == PTR_TO_PACKET_META &&
> reg_is_init_pkt_pointer(src_reg, PTR_TO_PACKET))) {
> /* pkt_data' <= pkt_end, pkt_meta' <= pkt_data */
> - find_good_pkt_pointers(other_branch, dst_reg,
> + find_good_buf_pointers(other_branch, dst_reg,
> dst_reg->type, false);
> } else if ((dst_reg->type == PTR_TO_PACKET_END &&
> src_reg->type == PTR_TO_PACKET) ||
> (reg_is_init_pkt_pointer(dst_reg, PTR_TO_PACKET) &&
> src_reg->type == PTR_TO_PACKET_META)) {
> /* pkt_end <= pkt_data', pkt_data <= pkt_meta' */
> - find_good_pkt_pointers(this_branch, src_reg,
> + find_good_buf_pointers(this_branch, src_reg,
> src_reg->type, true);
> + } else if (dst_reg->type == PTR_TO_BUFFER &&
> + src_reg->type == PTR_TO_BUFFER_END) {
> + /* buf' <= buf_end */
> + find_good_buf_pointers(other_branch, dst_reg,
> + dst_reg->type, true);
> + } else if (dst_reg->type == PTR_TO_BUFFER_END &&
> + src_reg->type == PTR_TO_BUFFER) {
> + /* buf_end <= buf' */
> + find_good_buf_pointers(this_branch, src_reg,
> + src_reg->type, false);
> } else {
> return false;
> }
> @@ -7972,7 +8052,7 @@ static int fixup_bpf_calls(struct bpf_verifier_env *env)
> */
> prog->cb_access = 1;
> env->prog->aux->stack_depth = MAX_BPF_STACK;
> - env->prog->aux->max_pkt_offset = MAX_PACKET_OFF;
> + env->prog->aux->max_pkt_offset = MAX_BUFFER_OFF;
>
> /* mark bpf_tail_call as different opcode to avoid
> * conditional branch in the interpeter for every normal