[PATCH 1/5] batman-adv: Trigger events for auto adjusted MTU

[PATCH 1/5] batman-adv: Trigger events for auto adjusted MTU

[Simon Wunderlich]

From: Sven Eckelmann <sven@narfation.org>

If an interface changes the MTU, it is expected that an NETDEV_PRECHANGEMTU
and NETDEV_CHANGEMTU notification events is triggered. This worked fine for
.ndo_change_mtu based changes because core networking code took care of it.
But for auto-adjustments after hard-interfaces changes, these events were
simply missing.

Due to this problem, non-batman-adv components weren't aware of MTU changes
and thus couldn't perform their own tasks correctly.

Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Cc: stable@vger.kernel.org
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/hard-interface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index 41c1ad33d009..ae5762af0146 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -630,7 +630,7 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
  */
 void batadv_update_min_mtu(struct net_device *soft_iface)
 {
-	soft_iface->mtu = batadv_hardif_min_mtu(soft_iface);
+	dev_set_mtu(soft_iface, batadv_hardif_min_mtu(soft_iface));
 
 	/* Check if the local translate table should be cleaned up to match a
 	 * new (and smaller) MTU.
-- 
2.39.2

Re: [PATCH 1/5] batman-adv: Trigger events for auto adjusted MTU

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Simon Wunderlich <sw@simonwunderlich.de>:

On Wed, 16 Aug 2023 18:33:14 +0200 you wrote:
> From: Sven Eckelmann <sven@narfation.org>
> 
> If an interface changes the MTU, it is expected that an NETDEV_PRECHANGEMTU
> and NETDEV_CHANGEMTU notification events is triggered. This worked fine for
> .ndo_change_mtu based changes because core networking code took care of it.
> But for auto-adjustments after hard-interfaces changes, these events were
> simply missing.
> 
> [...]

Here is the summary with links:
  - [1/5] batman-adv: Trigger events for auto adjusted MTU
    https://git.kernel.org/netdev/net/c/c6a953cce8d0
  - [2/5] batman-adv: Don't increase MTU when set by user
    https://git.kernel.org/netdev/net/c/d8e42a2b0add
  - [3/5] batman-adv: Do not get eth header before batadv_check_management_packet
    https://git.kernel.org/netdev/net/c/eac27a41ab64
  - [4/5] batman-adv: Fix TT global entry leak when client roamed back
    https://git.kernel.org/netdev/net/c/d25ddb7e788d
  - [5/5] batman-adv: Fix batadv_v_ogm_aggr_send memory leak
    https://git.kernel.org/netdev/net/c/421d467dc2d4

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

[PATCH 2/5] batman-adv: Don't increase MTU when set by user

[Simon Wunderlich]

From: Sven Eckelmann <sven@narfation.org>

If the user set an MTU value, it usually means that there are special
requirements for the MTU. But if an interface gots activated, the MTU was
always recalculated and then the user set value was overwritten.

The only reason why this user set value has to be overwritten, is when the
MTU has to be decreased because batman-adv is not able to transfer packets
with the user specified size.

Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Cc: stable@vger.kernel.org
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/hard-interface.c | 14 +++++++++++++-
 net/batman-adv/soft-interface.c |  3 +++
 net/batman-adv/types.h          |  6 ++++++
 3 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/hard-interface.c b/net/batman-adv/hard-interface.c
index ae5762af0146..24c9c0c3f316 100644
--- a/net/batman-adv/hard-interface.c
+++ b/net/batman-adv/hard-interface.c
@@ -630,7 +630,19 @@ int batadv_hardif_min_mtu(struct net_device *soft_iface)
  */
 void batadv_update_min_mtu(struct net_device *soft_iface)
 {
-	dev_set_mtu(soft_iface, batadv_hardif_min_mtu(soft_iface));
+	struct batadv_priv *bat_priv = netdev_priv(soft_iface);
+	int limit_mtu;
+	int mtu;
+
+	mtu = batadv_hardif_min_mtu(soft_iface);
+
+	if (bat_priv->mtu_set_by_user)
+		limit_mtu = bat_priv->mtu_set_by_user;
+	else
+		limit_mtu = ETH_DATA_LEN;
+
+	mtu = min(mtu, limit_mtu);
+	dev_set_mtu(soft_iface, mtu);
 
 	/* Check if the local translate table should be cleaned up to match a
 	 * new (and smaller) MTU.
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
index d3fdf82282af..85d00dc9ce32 100644
--- a/net/batman-adv/soft-interface.c
+++ b/net/batman-adv/soft-interface.c
@@ -153,11 +153,14 @@ static int batadv_interface_set_mac_addr(struct net_device *dev, void *p)
 
 static int batadv_interface_change_mtu(struct net_device *dev, int new_mtu)
 {
+	struct batadv_priv *bat_priv = netdev_priv(dev);
+
 	/* check ranges */
 	if (new_mtu < 68 || new_mtu > batadv_hardif_min_mtu(dev))
 		return -EINVAL;
 
 	dev->mtu = new_mtu;
+	bat_priv->mtu_set_by_user = new_mtu;
 
 	return 0;
 }
diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h
index ca9449ec9836..cf1a0eafe3ab 100644
--- a/net/batman-adv/types.h
+++ b/net/batman-adv/types.h
@@ -1546,6 +1546,12 @@ struct batadv_priv {
 	/** @soft_iface: net device which holds this struct as private data */
 	struct net_device *soft_iface;
 
+	/**
+	 * @mtu_set_by_user: MTU was set once by user
+	 * protected by rtnl_lock
+	 */
+	int mtu_set_by_user;
+
 	/**
 	 * @bat_counters: mesh internal traffic statistic counters (see
 	 *  batadv_counters)
-- 
2.39.2

[PATCH 3/5] batman-adv: Do not get eth header before batadv_check_management_packet

[Simon Wunderlich]

From: Remi Pommarel <repk@triplefau.lt>

If received skb in batadv_v_elp_packet_recv or batadv_v_ogm_packet_recv
is either cloned or non linearized then its data buffer will be
reallocated by batadv_check_management_packet when skb_cow or
skb_linearize get called. Thus geting ethernet header address inside
skb data buffer before batadv_check_management_packet had any chance to
reallocate it could lead to the following kernel panic:

  Unable to handle kernel paging request at virtual address ffffff8020ab069a
  Mem abort info:
    ESR = 0x96000007
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
    FSC = 0x07: level 3 translation fault
  Data abort info:
    ISV = 0, ISS = 0x00000007
    CM = 0, WnR = 0
  swapper pgtable: 4k pages, 39-bit VAs, pgdp=0000000040f45000
  [ffffff8020ab069a] pgd=180000007fffa003, p4d=180000007fffa003, pud=180000007fffa003, pmd=180000007fefe003, pte=0068000020ab0706
  Internal error: Oops: 96000007 [#1] SMP
  Modules linked in: ahci_mvebu libahci_platform libahci dvb_usb_af9035 dvb_usb_dib0700 dib0070 dib7000m dibx000_common ath11k_pci ath10k_pci ath10k_core mwl8k_new nf_nat_sip nf_conntrack_sip xhci_plat_hcd xhci_hcd nf_nat_pptp nf_conntrack_pptp at24 sbsa_gwdt
  CPU: 1 PID: 16 Comm: ksoftirqd/1 Not tainted 5.15.42-00066-g3242268d425c-dirty #550
  Hardware name: A8k (DT)
  pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
  pc : batadv_is_my_mac+0x60/0xc0
  lr : batadv_v_ogm_packet_recv+0x98/0x5d0
  sp : ffffff8000183820
  x29: ffffff8000183820 x28: 0000000000000001 x27: ffffff8014f9af00
  x26: 0000000000000000 x25: 0000000000000543 x24: 0000000000000003
  x23: ffffff8020ab0580 x22: 0000000000000110 x21: ffffff80168ae880
  x20: 0000000000000000 x19: ffffff800b561000 x18: 0000000000000000
  x17: 0000000000000000 x16: 0000000000000000 x15: 00dc098924ae0032
  x14: 0f0405433e0054b0 x13: ffffffff00000080 x12: 0000004000000001
  x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
  x8 : 0000000000000000 x7 : ffffffc076dae000 x6 : ffffff8000183700
  x5 : ffffffc00955e698 x4 : ffffff80168ae000 x3 : ffffff80059cf000
  x2 : ffffff800b561000 x1 : ffffff8020ab0696 x0 : ffffff80168ae880
  Call trace:
   batadv_is_my_mac+0x60/0xc0
   batadv_v_ogm_packet_recv+0x98/0x5d0
   batadv_batman_skb_recv+0x1b8/0x244
   __netif_receive_skb_core.isra.0+0x440/0xc74
   __netif_receive_skb_one_core+0x14/0x20
   netif_receive_skb+0x68/0x140
   br_pass_frame_up+0x70/0x80
   br_handle_frame_finish+0x108/0x284
   br_handle_frame+0x190/0x250
   __netif_receive_skb_core.isra.0+0x240/0xc74
   __netif_receive_skb_list_core+0x6c/0x90
   netif_receive_skb_list_internal+0x1f4/0x310
   napi_complete_done+0x64/0x1d0
   gro_cell_poll+0x7c/0xa0
   __napi_poll+0x34/0x174
   net_rx_action+0xf8/0x2a0
   _stext+0x12c/0x2ac
   run_ksoftirqd+0x4c/0x7c
   smpboot_thread_fn+0x120/0x210
   kthread+0x140/0x150
   ret_from_fork+0x10/0x20
  Code: f9403844 eb03009f 54fffee1 f94

Thus ethernet header address should only be fetched after
batadv_check_management_packet has been called.

Fixes: 0da0035942d4 ("batman-adv: OGMv2 - add basic infrastructure")
Cc: stable@vger.kernel.org
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/bat_v_elp.c | 3 ++-
 net/batman-adv/bat_v_ogm.c | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c
index acff565849ae..1d704574e6bf 100644
--- a/net/batman-adv/bat_v_elp.c
+++ b/net/batman-adv/bat_v_elp.c
@@ -505,7 +505,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb,
 	struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct batadv_elp_packet *elp_packet;
 	struct batadv_hard_iface *primary_if;
-	struct ethhdr *ethhdr = (struct ethhdr *)skb_mac_header(skb);
+	struct ethhdr *ethhdr;
 	bool res;
 	int ret = NET_RX_DROP;
 
@@ -513,6 +513,7 @@ int batadv_v_elp_packet_recv(struct sk_buff *skb,
 	if (!res)
 		goto free_skb;
 
+	ethhdr = eth_hdr(skb);
 	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 		goto free_skb;
 
diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index e710e9afe78f..84eac41d4658 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -985,7 +985,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv = netdev_priv(if_incoming->soft_iface);
 	struct batadv_ogm2_packet *ogm_packet;
-	struct ethhdr *ethhdr = eth_hdr(skb);
+	struct ethhdr *ethhdr;
 	int ogm_offset;
 	u8 *packet_pos;
 	int ret = NET_RX_DROP;
@@ -999,6 +999,7 @@ int batadv_v_ogm_packet_recv(struct sk_buff *skb,
 	if (!batadv_check_management_packet(skb, if_incoming, BATADV_OGM2_HLEN))
 		goto free_skb;
 
+	ethhdr = eth_hdr(skb);
 	if (batadv_is_my_mac(bat_priv, ethhdr->h_source))
 		goto free_skb;
 
-- 
2.39.2

[PATCH 4/5] batman-adv: Fix TT global entry leak when client roamed back

[Simon Wunderlich]

From: Remi Pommarel <repk@triplefau.lt>

When a client roamed back to a node before it got time to destroy the
pending local entry (i.e. within the same originator interval) the old
global one is directly removed from hash table and left as such.

But because this entry had an extra reference taken at lookup (i.e using
batadv_tt_global_hash_find) there is no way its memory will be reclaimed
at any time causing the following memory leak:

  unreferenced object 0xffff0000073c8000 (size 18560):
    comm "softirq", pid 0, jiffies 4294907738 (age 228.644s)
    hex dump (first 32 bytes):
      06 31 ac 12 c7 7a 05 00 01 00 00 00 00 00 00 00  .1...z..........
      2c ad be 08 00 80 ff ff 6c b6 be 08 00 80 ff ff  ,.......l.......
    backtrace:
      [<00000000ee6e0ffa>] kmem_cache_alloc+0x1b4/0x300
      [<000000000ff2fdbc>] batadv_tt_global_add+0x700/0xe20
      [<00000000443897c7>] _batadv_tt_update_changes+0x21c/0x790
      [<000000005dd90463>] batadv_tt_update_changes+0x3c/0x110
      [<00000000a2d7fc57>] batadv_tt_tvlv_unicast_handler_v1+0xafc/0xe10
      [<0000000011793f2a>] batadv_tvlv_containers_process+0x168/0x2b0
      [<00000000b7cbe2ef>] batadv_recv_unicast_tvlv+0xec/0x1f4
      [<0000000042aef1d8>] batadv_batman_skb_recv+0x25c/0x3a0
      [<00000000bbd8b0a2>] __netif_receive_skb_core.isra.0+0x7a8/0xe90
      [<000000004033d428>] __netif_receive_skb_one_core+0x64/0x74
      [<000000000f39a009>] __netif_receive_skb+0x48/0xe0
      [<00000000f2cd8888>] process_backlog+0x174/0x344
      [<00000000507d6564>] __napi_poll+0x58/0x1f4
      [<00000000b64ef9eb>] net_rx_action+0x504/0x590
      [<00000000056fa5e4>] _stext+0x1b8/0x418
      [<00000000878879d6>] run_ksoftirqd+0x74/0xa4
  unreferenced object 0xffff00000bae1a80 (size 56):
    comm "softirq", pid 0, jiffies 4294910888 (age 216.092s)
    hex dump (first 32 bytes):
      00 78 b1 0b 00 00 ff ff 0d 50 00 00 00 00 00 00  .x.......P......
      00 00 00 00 00 00 00 00 50 c8 3c 07 00 00 ff ff  ........P.<.....
    backtrace:
      [<00000000ee6e0ffa>] kmem_cache_alloc+0x1b4/0x300
      [<00000000d9aaa49e>] batadv_tt_global_add+0x53c/0xe20
      [<00000000443897c7>] _batadv_tt_update_changes+0x21c/0x790
      [<000000005dd90463>] batadv_tt_update_changes+0x3c/0x110
      [<00000000a2d7fc57>] batadv_tt_tvlv_unicast_handler_v1+0xafc/0xe10
      [<0000000011793f2a>] batadv_tvlv_containers_process+0x168/0x2b0
      [<00000000b7cbe2ef>] batadv_recv_unicast_tvlv+0xec/0x1f4
      [<0000000042aef1d8>] batadv_batman_skb_recv+0x25c/0x3a0
      [<00000000bbd8b0a2>] __netif_receive_skb_core.isra.0+0x7a8/0xe90
      [<000000004033d428>] __netif_receive_skb_one_core+0x64/0x74
      [<000000000f39a009>] __netif_receive_skb+0x48/0xe0
      [<00000000f2cd8888>] process_backlog+0x174/0x344
      [<00000000507d6564>] __napi_poll+0x58/0x1f4
      [<00000000b64ef9eb>] net_rx_action+0x504/0x590
      [<00000000056fa5e4>] _stext+0x1b8/0x418
      [<00000000878879d6>] run_ksoftirqd+0x74/0xa4

Releasing the extra reference from batadv_tt_global_hash_find even at
roam back when batadv_tt_global_free is called fixes this memory leak.

Cc: stable@vger.kernel.org
Fixes: 068ee6e204e1 ("batman-adv: roaming handling mechanism redesign")
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Signed-off-by; Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/translation-table.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index 36ca31252a73..b95c36765d04 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -774,7 +774,6 @@ bool batadv_tt_local_add(struct net_device *soft_iface, const u8 *addr,
 		if (roamed_back) {
 			batadv_tt_global_free(bat_priv, tt_global,
 					      "Roaming canceled");
-			tt_global = NULL;
 		} else {
 			/* The global entry has to be marked as ROAMING and
 			 * has to be kept for consistency purpose
-- 
2.39.2

[PATCH 5/5] batman-adv: Fix batadv_v_ogm_aggr_send memory leak

[Simon Wunderlich]

From: Remi Pommarel <repk@triplefau.lt>

When batadv_v_ogm_aggr_send is called for an inactive interface, the skb
is silently dropped by batadv_v_ogm_send_to_if() but never freed causing
the following memory leak:

  unreferenced object 0xffff00000c164800 (size 512):
    comm "kworker/u8:1", pid 2648, jiffies 4295122303 (age 97.656s)
    hex dump (first 32 bytes):
      00 80 af 09 00 00 ff ff e1 09 00 00 75 01 60 83  ............u.`.
      1f 00 00 00 b8 00 00 00 15 00 05 00 da e3 d3 64  ...............d
    backtrace:
      [<0000000007ad20f6>] __kmalloc_track_caller+0x1a8/0x310
      [<00000000d1029e55>] kmalloc_reserve.constprop.0+0x70/0x13c
      [<000000008b9d4183>] __alloc_skb+0xec/0x1fc
      [<00000000c7af5051>] __netdev_alloc_skb+0x48/0x23c
      [<00000000642ee5f5>] batadv_v_ogm_aggr_send+0x50/0x36c
      [<0000000088660bd7>] batadv_v_ogm_aggr_work+0x24/0x40
      [<0000000042fc2606>] process_one_work+0x3b0/0x610
      [<000000002f2a0b1c>] worker_thread+0xa0/0x690
      [<0000000059fae5d4>] kthread+0x1fc/0x210
      [<000000000c587d3a>] ret_from_fork+0x10/0x20

Free the skb in that case to fix this leak.

Cc: stable@vger.kernel.org
Fixes: 0da0035942d4 ("batman-adv: OGMv2 - add basic infrastructure")
Signed-off-by: Remi Pommarel <repk@triplefau.lt>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
---
 net/batman-adv/bat_v_ogm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/batman-adv/bat_v_ogm.c b/net/batman-adv/bat_v_ogm.c
index 84eac41d4658..e503ee0d896b 100644
--- a/net/batman-adv/bat_v_ogm.c
+++ b/net/batman-adv/bat_v_ogm.c
@@ -123,8 +123,10 @@ static void batadv_v_ogm_send_to_if(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv = netdev_priv(hard_iface->soft_iface);
 
-	if (hard_iface->if_status != BATADV_IF_ACTIVE)
+	if (hard_iface->if_status != BATADV_IF_ACTIVE) {
+		kfree_skb(skb);
 		return;
+	}
 
 	batadv_inc_counter(bat_priv, BATADV_CNT_MGMT_TX);
 	batadv_add_counter(bat_priv, BATADV_CNT_MGMT_TX_BYTES,
-- 
2.39.2