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authorDavid S. Miller <davem@davemloft.net>2021-09-28 13:52:46 +0100
committerDavid S. Miller <davem@davemloft.net>2021-09-28 13:52:46 +0100
commit4ccb9f03fee7b20484187ba7e25a7b9b79fe63d5 (patch)
tree3e6fd2e4a67b6e2be99331518f3c7c541367ad3d /arch
parentc894b51e2a23c8c00acb3cea5045c5b70691e790 (diff)
parentced185824c89b60e65b5a2606954c098320cdfb8 (diff)
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> ,
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/net/bpf_jit.c57
-rw-r--r--arch/x86/net/bpf_jit_comp.c66
2 files changed, 91 insertions, 32 deletions
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c
index 0af88622c619..cb6d22439f71 100644
--- a/arch/mips/net/bpf_jit.c
+++ b/arch/mips/net/bpf_jit.c
@@ -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 */
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 0fe6aacef3db..9ea57389c554 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -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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