Merge tag 'net-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

Pull networking fixes from Jakub Kicinski:
 "Networking fixes for 5.10-rc5, including fixes from the WiFi
  (mac80211), can and bpf (including the strncpy_from_user fix).

  Current release - regressions:

   - mac80211: fix memory leak of filtered powersave frames

   - mac80211: free sta in sta_info_insert_finish() on errors to avoid
     sleeping in atomic context

   - netlabel: fix an uninitialized variable warning added in -rc4

  Previous release - regressions:

   - vsock: forward all packets to the host when no H2G is registered,
     un-breaking AWS Nitro Enclaves

   - net: Exempt multicast addresses from five-second neighbor lifetime
     requirement, decreasing the chances neighbor tables fill up

   - net/tls: fix corrupted data in recvmsg

   - qed: fix ILT configuration of SRC block

   - can: m_can: process interrupt only when not runtime suspended

  Previous release - always broken:

   - page_frag: Recover from memory pressure by not recycling pages
     allocating from the reserves

   - strncpy_from_user: Mask out bytes after NUL terminator

   - ip_tunnels: Set tunnel option flag only when tunnel metadata is
     present, always setting it confuses Open vSwitch

   - bpf, sockmap:
      - Fix partial copy_page_to_iter so progress can still be made
      - Fix socket memory accounting and obeying SO_RCVBUF

   - net: Have netpoll bring-up DSA management interface

   - net: bridge: add missing counters to ndo_get_stats64 callback

   - tcp: brr: only postpone PROBE_RTT if RTT is < current min_rtt

   - enetc: Workaround MDIO register access HW bug

   - net/ncsi: move netlink family registration to a subsystem init,
     instead of tying it to driver probe

   - net: ftgmac100: unregister NC-SI when removing driver to avoid
     crash

   - lan743x:
      - prevent interrupt storm on open
      - fix freeing skbs in the wrong context

   - net/mlx5e: Fix socket refcount leak on kTLS RX resync

   - net: dsa: mv88e6xxx: Avoid VLAN database corruption on 6097

   - fix 21 unset return codes and other mistakes on error paths, mostly
     detected by the Hulk Robot"

* tag 'net-5.10-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (115 commits)
  fail_function: Remove a redundant mutex unlock
  selftest/bpf: Test bpf_probe_read_user_str() strips trailing bytes after NUL
  lib/strncpy_from_user.c: Mask out bytes after NUL terminator.
  net/smc: fix direct access to ib_gid_addr->ndev in smc_ib_determine_gid()
  net/smc: fix matching of existing link groups
  ipv6: Remove dependency of ipv6_frag_thdr_truncated on ipv6 module
  libbpf: Fix VERSIONED_SYM_COUNT number parsing
  net/mlx4_core: Fix init_hca fields offset
  atm: nicstar: Unmap DMA on send error
  page_frag: Recover from memory pressure
  net: dsa: mv88e6xxx: Wait for EEPROM done after HW reset
  mlxsw: core: Use variable timeout for EMAD retries
  mlxsw: Fix firmware flashing
  net: Have netpoll bring-up DSA management interface
  atl1e: fix error return code in atl1e_probe()
  atl1c: fix error return code in atl1c_probe()
  ah6: fix error return code in ah6_input()
  net: usb: qmi_wwan: Set DTR quirk for MR400
  can: m_can: process interrupt only when not runtime suspended
  can: flexcan: flexcan_chip_start(): fix erroneous flexcan_transceiver_enable() during bus-off recovery
  ...

3 files changed, 29 insertions, 6 deletions

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 6200519582a6..1388bf733071 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -7786,9 +7786,11 @@ static int check_return_code(struct bpf_verifier_env *env)
 	struct tnum range = tnum_range(0, 1);
 	enum bpf_prog_type prog_type = resolve_prog_type(env->prog);
 	int err;
+	const bool is_subprog = env->cur_state->frame[0]->subprogno;
 
 	/* LSM and struct_ops func-ptr's return type could be "void" */
-	if ((prog_type == BPF_PROG_TYPE_STRUCT_OPS ||
+	if (!is_subprog &&
+	    (prog_type == BPF_PROG_TYPE_STRUCT_OPS ||
 	     prog_type == BPF_PROG_TYPE_LSM) &&
 	    !prog->aux->attach_func_proto->type)
 		return 0;
@@ -7808,6 +7810,16 @@ static int check_return_code(struct bpf_verifier_env *env)
 		return -EACCES;
 	}
 
+	reg = cur_regs(env) + BPF_REG_0;
+	if (is_subprog) {
+		if (reg->type != SCALAR_VALUE) {
+			verbose(env, "At subprogram exit the register R0 is not a scalar value (%s)\n",
+				reg_type_str[reg->type]);
+			return -EINVAL;
+		}
+		return 0;
+	}
+
 	switch (prog_type) {
 	case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
 		if (env->prog->expected_attach_type == BPF_CGROUP_UDP4_RECVMSG ||
@@ -7861,7 +7873,6 @@ static int check_return_code(struct bpf_verifier_env *env)
 		return 0;
 	}
 
-	reg = cur_regs(env) + BPF_REG_0;
 	if (reg->type != SCALAR_VALUE) {
 		verbose(env, "At program exit the register R0 is not a known value (%s)\n",
 			reg_type_str[reg->type]);
@@ -9572,12 +9583,13 @@ static int check_pseudo_btf_id(struct bpf_verifier_env *env,
 			       struct bpf_insn *insn,
 			       struct bpf_insn_aux_data *aux)
 {
-	u32 datasec_id, type, id = insn->imm;
 	const struct btf_var_secinfo *vsi;
 	const struct btf_type *datasec;
 	const struct btf_type *t;
 	const char *sym_name;
 	bool percpu = false;
+	u32 type, id = insn->imm;
+	s32 datasec_id;
 	u64 addr;
 	int i;
 
diff --git a/kernel/fail_function.c b/kernel/fail_function.c
index 63b349168da7..b0b1ad93fa95 100644
--- a/kernel/fail_function.c
+++ b/kernel/fail_function.c
@@ -253,7 +253,7 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 
 	if (copy_from_user(buf, buffer, count)) {
 		ret = -EFAULT;
-		goto out;
+		goto out_free;
 	}
 	buf[count] = '\0';
 	sym = strstrip(buf);
@@ -307,8 +307,9 @@ static ssize_t fei_write(struct file *file, const char __user *buffer,
 		ret = count;
 	}
 out:
-	kfree(buf);
 	mutex_unlock(&fei_lock);
+out_free:
+	kfree(buf);
 	return ret;
 }
 
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 4517c8b66518..048c655315f1 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -181,6 +181,16 @@ bpf_probe_read_user_str_common(void *dst, u32 size,
 {
 	int ret;
 
+	/*
+	 * NB: We rely on strncpy_from_user() not copying junk past the NUL
+	 * terminator into `dst`.
+	 *
+	 * strncpy_from_user() does long-sized strides in the fast path. If the
+	 * strncpy does not mask out the bytes after the NUL in `unsafe_ptr`,
+	 * then there could be junk after the NUL in `dst`. If user takes `dst`
+	 * and keys a hash map with it, then semantically identical strings can
+	 * occupy multiple entries in the map.
+	 */
 	ret = strncpy_from_user_nofault(dst, unsafe_ptr, size);
 	if (unlikely(ret < 0))
 		memset(dst, 0, size);
@@ -1198,7 +1208,7 @@ static int bpf_btf_printf_prepare(struct btf_ptr *ptr, u32 btf_ptr_size,
 	*btf = bpf_get_btf_vmlinux();
 
 	if (IS_ERR_OR_NULL(*btf))
-		return PTR_ERR(*btf);
+		return IS_ERR(*btf) ? PTR_ERR(*btf) : -EINVAL;
 
 	if (ptr->type_id > 0)
 		*btf_id = ptr->type_id;