Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf

Daniel Borkmann says:

====================
pull-request: bpf 2021-09-28

The following pull-request contains BPF updates for your *net* tree.

We've added 10 non-merge commits during the last 14 day(s) which contain
a total of 11 files changed, 139 insertions(+), 53 deletions(-).

The main changes are:

1) Fix MIPS JIT jump code emission for too large offsets, from Piotr Krysiuk.

2) Fix x86 JIT atomic/fetch emission when dst reg maps to rax, from Johan Almbladh.

3) Fix cgroup_sk_alloc corner case when called from interrupt, from Daniel Borkmann.

4) Fix segfault in libbpf's linker for objects without BTF, from Kumar Kartikeya Dwivedi.

5) Fix bpf_jit_charge_modmem for applications with CAP_BPF, from Lorenz Bauer.

6) Fix return value handling for struct_ops BPF programs, from Hou Tao.

7) Various fixes to BPF selftests, from Jiri Benc.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
,
This commit is contained in:
David S. Miller 2021-09-28 13:52:46 +01:00
commit 4ccb9f03fe
11 changed files with 139 additions and 53 deletions

View File

@ -3384,9 +3384,11 @@ F: Documentation/networking/filter.rst
F: Documentation/userspace-api/ebpf/
F: arch/*/net/*
F: include/linux/bpf*
F: include/linux/btf*
F: include/linux/filter.h
F: include/trace/events/xdp.h
F: include/uapi/linux/bpf*
F: include/uapi/linux/btf*
F: include/uapi/linux/filter.h
F: kernel/bpf/
F: kernel/trace/bpf_trace.c

View File

@ -662,6 +662,11 @@ static void build_epilogue(struct jit_ctx *ctx)
((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative : func) : \
func##_positive)
static bool is_bad_offset(int b_off)
{
return b_off > 0x1ffff || b_off < -0x20000;
}
static int build_body(struct jit_ctx *ctx)
{
const struct bpf_prog *prog = ctx->skf;
@ -728,7 +733,10 @@ load_common:
/* Load return register on DS for failures */
emit_reg_move(r_ret, r_zero, ctx);
/* Return with error */
emit_b(b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_b(b_off, ctx);
emit_nop(ctx);
break;
case BPF_LD | BPF_W | BPF_IND:
@ -775,8 +783,10 @@ load_ind:
emit_jalr(MIPS_R_RA, r_s0, ctx);
emit_reg_move(MIPS_R_A0, r_skb, ctx); /* delay slot */
/* Check the error value */
emit_bcond(MIPS_COND_NE, r_ret, 0,
b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_bcond(MIPS_COND_NE, r_ret, 0, b_off, ctx);
emit_reg_move(r_ret, r_zero, ctx);
/* We are good */
/* X <- P[1:K] & 0xf */
@ -855,8 +865,10 @@ load_ind:
/* A /= X */
ctx->flags |= SEEN_X | SEEN_A;
/* Check if r_X is zero */
emit_bcond(MIPS_COND_EQ, r_X, r_zero,
b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_bcond(MIPS_COND_EQ, r_X, r_zero, b_off, ctx);
emit_load_imm(r_ret, 0, ctx); /* delay slot */
emit_div(r_A, r_X, ctx);
break;
@ -864,8 +876,10 @@ load_ind:
/* A %= X */
ctx->flags |= SEEN_X | SEEN_A;
/* Check if r_X is zero */
emit_bcond(MIPS_COND_EQ, r_X, r_zero,
b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_bcond(MIPS_COND_EQ, r_X, r_zero, b_off, ctx);
emit_load_imm(r_ret, 0, ctx); /* delay slot */
emit_mod(r_A, r_X, ctx);
break;
@ -926,7 +940,10 @@ load_ind:
break;
case BPF_JMP | BPF_JA:
/* pc += K */
emit_b(b_imm(i + k + 1, ctx), ctx);
b_off = b_imm(i + k + 1, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_b(b_off, ctx);
emit_nop(ctx);
break;
case BPF_JMP | BPF_JEQ | BPF_K:
@ -1056,12 +1073,16 @@ jmp_cmp:
break;
case BPF_RET | BPF_A:
ctx->flags |= SEEN_A;
if (i != prog->len - 1)
if (i != prog->len - 1) {
/*
* If this is not the last instruction
* then jump to the epilogue
*/
emit_b(b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_b(b_off, ctx);
}
emit_reg_move(r_ret, r_A, ctx); /* delay slot */
break;
case BPF_RET | BPF_K:
@ -1075,7 +1096,10 @@ jmp_cmp:
* If this is not the last instruction
* then jump to the epilogue
*/
emit_b(b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_b(b_off, ctx);
emit_nop(ctx);
}
break;
@ -1133,8 +1157,10 @@ jmp_cmp:
/* Load *dev pointer */
emit_load_ptr(r_s0, r_skb, off, ctx);
/* error (0) in the delay slot */
emit_bcond(MIPS_COND_EQ, r_s0, r_zero,
b_imm(prog->len, ctx), ctx);
b_off = b_imm(prog->len, ctx);
if (is_bad_offset(b_off))
return -E2BIG;
emit_bcond(MIPS_COND_EQ, r_s0, r_zero, b_off, ctx);
emit_reg_move(r_ret, r_zero, ctx);
if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
BUILD_BUG_ON(sizeof_field(struct net_device, ifindex) != 4);
@ -1244,7 +1270,10 @@ void bpf_jit_compile(struct bpf_prog *fp)
/* Generate the actual JIT code */
build_prologue(&ctx);
build_body(&ctx);
if (build_body(&ctx)) {
module_memfree(ctx.target);
goto out;
}
build_epilogue(&ctx);
/* Update the icache */

View File

@ -1341,9 +1341,10 @@ st: if (is_imm8(insn->off))
if (insn->imm == (BPF_AND | BPF_FETCH) ||
insn->imm == (BPF_OR | BPF_FETCH) ||
insn->imm == (BPF_XOR | BPF_FETCH)) {
u8 *branch_target;
bool is64 = BPF_SIZE(insn->code) == BPF_DW;
u32 real_src_reg = src_reg;
u32 real_dst_reg = dst_reg;
u8 *branch_target;
/*
* Can't be implemented with a single x86 insn.
@ -1354,11 +1355,13 @@ st: if (is_imm8(insn->off))
emit_mov_reg(&prog, true, BPF_REG_AX, BPF_REG_0);
if (src_reg == BPF_REG_0)
real_src_reg = BPF_REG_AX;
if (dst_reg == BPF_REG_0)
real_dst_reg = BPF_REG_AX;
branch_target = prog;
/* Load old value */
emit_ldx(&prog, BPF_SIZE(insn->code),
BPF_REG_0, dst_reg, insn->off);
BPF_REG_0, real_dst_reg, insn->off);
/*
* Perform the (commutative) operation locally,
* put the result in the AUX_REG.
@ -1369,7 +1372,8 @@ st: if (is_imm8(insn->off))
add_2reg(0xC0, AUX_REG, real_src_reg));
/* Attempt to swap in new value */
err = emit_atomic(&prog, BPF_CMPXCHG,
dst_reg, AUX_REG, insn->off,
real_dst_reg, AUX_REG,
insn->off,
BPF_SIZE(insn->code));
if (WARN_ON(err))
return err;
@ -1383,11 +1387,10 @@ st: if (is_imm8(insn->off))
/* Restore R0 after clobbering RAX */
emit_mov_reg(&prog, true, BPF_REG_0, BPF_REG_AX);
break;
}
err = emit_atomic(&prog, insn->imm, dst_reg, src_reg,
insn->off, BPF_SIZE(insn->code));
insn->off, BPF_SIZE(insn->code));
if (err)
return err;
break;
@ -1744,7 +1747,7 @@ static void restore_regs(const struct btf_func_model *m, u8 **prog, int nr_args,
}
static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
struct bpf_prog *p, int stack_size, bool mod_ret)
struct bpf_prog *p, int stack_size, bool save_ret)
{
u8 *prog = *pprog;
u8 *jmp_insn;
@ -1777,11 +1780,15 @@ static int invoke_bpf_prog(const struct btf_func_model *m, u8 **pprog,
if (emit_call(&prog, p->bpf_func, prog))
return -EINVAL;
/* BPF_TRAMP_MODIFY_RETURN trampolines can modify the return
/*
* BPF_TRAMP_MODIFY_RETURN trampolines can modify the return
* of the previous call which is then passed on the stack to
* the next BPF program.
*
* BPF_TRAMP_FENTRY trampoline may need to return the return
* value of BPF_PROG_TYPE_STRUCT_OPS prog.
*/
if (mod_ret)
if (save_ret)
emit_stx(&prog, BPF_DW, BPF_REG_FP, BPF_REG_0, -8);
/* replace 2 nops with JE insn, since jmp target is known */
@ -1828,13 +1835,15 @@ static int emit_cond_near_jump(u8 **pprog, void *func, void *ip, u8 jmp_cond)
}
static int invoke_bpf(const struct btf_func_model *m, u8 **pprog,
struct bpf_tramp_progs *tp, int stack_size)
struct bpf_tramp_progs *tp, int stack_size,
bool save_ret)
{
int i;
u8 *prog = *pprog;
for (i = 0; i < tp->nr_progs; i++) {
if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size, false))
if (invoke_bpf_prog(m, &prog, tp->progs[i], stack_size,
save_ret))
return -EINVAL;
}
*pprog = prog;
@ -1877,6 +1886,23 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog,
return 0;
}
static bool is_valid_bpf_tramp_flags(unsigned int flags)
{
if ((flags & BPF_TRAMP_F_RESTORE_REGS) &&
(flags & BPF_TRAMP_F_SKIP_FRAME))
return false;
/*
* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
* and it must be used alone.
*/
if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) &&
(flags & ~BPF_TRAMP_F_RET_FENTRY_RET))
return false;
return true;
}
/* Example:
* __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
* its 'struct btf_func_model' will be nr_args=2
@ -1949,17 +1975,19 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
struct bpf_tramp_progs *fmod_ret = &tprogs[BPF_TRAMP_MODIFY_RETURN];
u8 **branches = NULL;
u8 *prog;
bool save_ret;
/* x86-64 supports up to 6 arguments. 7+ can be added in the future */
if (nr_args > 6)
return -ENOTSUPP;
if ((flags & BPF_TRAMP_F_RESTORE_REGS) &&
(flags & BPF_TRAMP_F_SKIP_FRAME))
if (!is_valid_bpf_tramp_flags(flags))
return -EINVAL;
if (flags & BPF_TRAMP_F_CALL_ORIG)
stack_size += 8; /* room for return value of orig_call */
/* room for return value of orig_call or fentry prog */
save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET);
if (save_ret)
stack_size += 8;
if (flags & BPF_TRAMP_F_IP_ARG)
stack_size += 8; /* room for IP address argument */
@ -2005,7 +2033,8 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
}
if (fentry->nr_progs)
if (invoke_bpf(m, &prog, fentry, stack_size))
if (invoke_bpf(m, &prog, fentry, stack_size,
flags & BPF_TRAMP_F_RET_FENTRY_RET))
return -EINVAL;
if (fmod_ret->nr_progs) {
@ -2052,7 +2081,7 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
}
if (fexit->nr_progs)
if (invoke_bpf(m, &prog, fexit, stack_size)) {
if (invoke_bpf(m, &prog, fexit, stack_size, false)) {
ret = -EINVAL;
goto cleanup;
}
@ -2072,9 +2101,10 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i
ret = -EINVAL;
goto cleanup;
}
/* restore original return value back into RAX */
emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, -8);
}
/* restore return value of orig_call or fentry prog back into RAX */
if (save_ret)
emit_ldx(&prog, BPF_DW, BPF_REG_0, BPF_REG_FP, -8);
EMIT1(0x5B); /* pop rbx */
EMIT1(0xC9); /* leave */

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@ -578,11 +578,12 @@ struct btf_func_model {
* programs only. Should not be used with normal calls and indirect calls.
*/
#define BPF_TRAMP_F_SKIP_FRAME BIT(2)
/* Store IP address of the caller on the trampoline stack,
* so it's available for trampoline's programs.
*/
#define BPF_TRAMP_F_IP_ARG BIT(3)
/* Return the return value of fentry prog. Only used by bpf_struct_ops. */
#define BPF_TRAMP_F_RET_FENTRY_RET BIT(4)
/* Each call __bpf_prog_enter + call bpf_func + call __bpf_prog_exit is ~50
* bytes on x86. Pick a number to fit into BPF_IMAGE_SIZE / 2

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@ -368,6 +368,7 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
const struct btf_type *mtype, *ptype;
struct bpf_prog *prog;
u32 moff;
u32 flags;
moff = btf_member_bit_offset(t, member) / 8;
ptype = btf_type_resolve_ptr(btf_vmlinux, member->type, NULL);
@ -431,10 +432,12 @@ static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key,
tprogs[BPF_TRAMP_FENTRY].progs[0] = prog;
tprogs[BPF_TRAMP_FENTRY].nr_progs = 1;
flags = st_ops->func_models[i].ret_size > 0 ?
BPF_TRAMP_F_RET_FENTRY_RET : 0;
err = arch_prepare_bpf_trampoline(NULL, image,
st_map->image + PAGE_SIZE,
&st_ops->func_models[i], 0,
tprogs, NULL);
&st_ops->func_models[i],
flags, tprogs, NULL);
if (err < 0)
goto reset_unlock;

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@ -827,7 +827,7 @@ int bpf_jit_charge_modmem(u32 pages)
{
if (atomic_long_add_return(pages, &bpf_jit_current) >
(bpf_jit_limit >> PAGE_SHIFT)) {
if (!capable(CAP_SYS_ADMIN)) {
if (!bpf_capable()) {
atomic_long_sub(pages, &bpf_jit_current);
return -EPERM;
}

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@ -6574,22 +6574,29 @@ int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v)
void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
{
/* Don't associate the sock with unrelated interrupted task's cgroup. */
if (in_interrupt())
return;
struct cgroup *cgroup;
rcu_read_lock();
/* Don't associate the sock with unrelated interrupted task's cgroup. */
if (in_interrupt()) {
cgroup = &cgrp_dfl_root.cgrp;
cgroup_get(cgroup);
goto out;
}
while (true) {
struct css_set *cset;
cset = task_css_set(current);
if (likely(cgroup_tryget(cset->dfl_cgrp))) {
skcd->cgroup = cset->dfl_cgrp;
cgroup_bpf_get(cset->dfl_cgrp);
cgroup = cset->dfl_cgrp;
break;
}
cpu_relax();
}
out:
skcd->cgroup = cgroup;
cgroup_bpf_get(cgroup);
rcu_read_unlock();
}

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@ -552,6 +552,12 @@ static void convert_skb_to___skb(struct sk_buff *skb, struct __sk_buff *__skb)
__skb->gso_segs = skb_shinfo(skb)->gso_segs;
}
static struct proto bpf_dummy_proto = {
.name = "bpf_dummy",
.owner = THIS_MODULE,
.obj_size = sizeof(struct sock),
};
int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
@ -596,20 +602,19 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
break;
}
sk = kzalloc(sizeof(struct sock), GFP_USER);
sk = sk_alloc(net, AF_UNSPEC, GFP_USER, &bpf_dummy_proto, 1);
if (!sk) {
kfree(data);
kfree(ctx);
return -ENOMEM;
}
sock_net_set(sk, net);
sock_init_data(NULL, sk);
skb = build_skb(data, 0);
if (!skb) {
kfree(data);
kfree(ctx);
kfree(sk);
sk_free(sk);
return -ENOMEM;
}
skb->sk = sk;
@ -682,8 +687,7 @@ out:
if (dev && dev != net->loopback_dev)
dev_put(dev);
kfree_skb(skb);
bpf_sk_storage_free(sk);
kfree(sk);
sk_free(sk);
kfree(ctx);
return ret;
}

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@ -1649,11 +1649,17 @@ static bool btf_is_non_static(const struct btf_type *t)
static int find_glob_sym_btf(struct src_obj *obj, Elf64_Sym *sym, const char *sym_name,
int *out_btf_sec_id, int *out_btf_id)
{
int i, j, n = btf__get_nr_types(obj->btf), m, btf_id = 0;
int i, j, n, m, btf_id = 0;
const struct btf_type *t;
const struct btf_var_secinfo *vi;
const char *name;
if (!obj->btf) {
pr_warn("failed to find BTF info for object '%s'\n", obj->filename);
return -EINVAL;
}
n = btf__get_nr_types(obj->btf);
for (i = 1; i <= n; i++) {
t = btf__type_by_id(obj->btf, i);

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@ -375,7 +375,8 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.o: \
$(TRUNNER_BPF_PROGS_DIR)/%.c \
$(TRUNNER_BPF_PROGS_DIR)/*.h \
$$(INCLUDE_DIR)/vmlinux.h \
$(wildcard $(BPFDIR)/bpf_*.h) | $(TRUNNER_OUTPUT)
$(wildcard $(BPFDIR)/bpf_*.h) \
| $(TRUNNER_OUTPUT) $$(BPFOBJ)
$$(call $(TRUNNER_BPF_BUILD_RULE),$$<,$$@, \
$(TRUNNER_BPF_CFLAGS))

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@ -112,6 +112,14 @@ setup()
ip netns add "${NS2}"
ip netns add "${NS3}"
# rp_filter gets confused by what these tests are doing, so disable it
ip netns exec ${NS1} sysctl -wq net.ipv4.conf.all.rp_filter=0
ip netns exec ${NS2} sysctl -wq net.ipv4.conf.all.rp_filter=0
ip netns exec ${NS3} sysctl -wq net.ipv4.conf.all.rp_filter=0
ip netns exec ${NS1} sysctl -wq net.ipv4.conf.default.rp_filter=0
ip netns exec ${NS2} sysctl -wq net.ipv4.conf.default.rp_filter=0
ip netns exec ${NS3} sysctl -wq net.ipv4.conf.default.rp_filter=0
ip link add veth1 type veth peer name veth2
ip link add veth3 type veth peer name veth4
ip link add veth5 type veth peer name veth6
@ -236,11 +244,6 @@ setup()
ip -netns ${NS1} -6 route add ${IPv6_GRE}/128 dev veth5 via ${IPv6_6} ${VRF}
ip -netns ${NS2} -6 route add ${IPv6_GRE}/128 dev veth7 via ${IPv6_8} ${VRF}
# rp_filter gets confused by what these tests are doing, so disable it
ip netns exec ${NS1} sysctl -wq net.ipv4.conf.all.rp_filter=0
ip netns exec ${NS2} sysctl -wq net.ipv4.conf.all.rp_filter=0
ip netns exec ${NS3} sysctl -wq net.ipv4.conf.all.rp_filter=0
TMPFILE=$(mktemp /tmp/test_lwt_ip_encap.XXXXXX)
sleep 1 # reduce flakiness