From: Erick Archer <erick.archer@outlook.com>
To: Marek Lindner <mareklindner@neomailbox.ch>,
Simon Wunderlich <sw@simonwunderlich.de>,
Antonio Quartulli <a@unstable.cc>,
Sven Eckelmann <sven@narfation.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Kees Cook <keescook@chromium.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: Erick Archer <erick.archer@outlook.com>,
b.a.t.m.a.n@lists.open-mesh.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: [PATCH] batman-adv: Add flex array to struct batadv_tvlv_tt_data
Date: Tue, 2 Apr 2024 19:23:01 +0200 [thread overview]
Message-ID: <AS8PR02MB7237987BF9DFCA030B330F658B3E2@AS8PR02MB7237.eurprd02.prod.outlook.com> (raw)
The "struct batadv_tvlv_tt_data" uses a dynamically sized set of
trailing elements. Specifically, it uses an array of structures of type
"batadv_tvlv_tt_vlan_data". So, use the preferred way in the kernel
declaring a flexible array [1].
The order in which the structure batadv_tvlv_tt_data and the structure
batadv_tvlv_tt_vlan_data are defined must be swap to avoid an incomplete
type error.
Also, avoid the open-coded arithmetic in memory allocator functions [2]
using the "struct_size" macro and use the "flex_array_size" helper to
clarify some calculations, when possible.
Moreover, the new structure member also allow us to avoid the open-coded
arithmetic on pointers in some situations. Take advantage of this.
This code was detected with the help of Coccinelle, and audited and
modified manually.
Link: https://www.kernel.org/doc/html/next/process/deprecated.html#zero-length-and-one-element-arrays [1]
Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
Signed-off-by: Erick Archer <erick.archer@outlook.com>
---
Hi,
I would like to add the "__counted_by(num_vlan)" tag to the new flex member
but I don't know if this line can affect it.
ntohs(tt_data->num_vlan)
If there is no problem I can send a v2 with the "__counted_by" tag.
The Coccinelle script used to detect this code pattern is the following:
virtual report
@rule1@
type t1;
type t2;
identifier i0;
identifier i1;
identifier i2;
identifier ALLOC =~ "kmalloc|kzalloc|kmalloc_node|kzalloc_node|vmalloc|vzalloc|kvmalloc|kvzalloc";
position p1;
@@
i0 = sizeof(t1) + sizeof(t2) * i1;
...
i2 = ALLOC@p1(..., i0, ...);
@script:python depends on report@
p1 << rule1.p1;
@@
msg = "WARNING: verify allocation on line %s" % (p1[0].line)
coccilib.report.print_report(p1[0],msg)
Regards,
Erick
---
include/uapi/linux/batadv_packet.h | 28 +++++++++---------
net/batman-adv/translation-table.c | 47 ++++++++++++------------------
2 files changed, 33 insertions(+), 42 deletions(-)
diff --git a/include/uapi/linux/batadv_packet.h b/include/uapi/linux/batadv_packet.h
index 6e25753015df..49cd345b84a7 100644
--- a/include/uapi/linux/batadv_packet.h
+++ b/include/uapi/linux/batadv_packet.h
@@ -592,19 +592,6 @@ struct batadv_tvlv_gateway_data {
__be32 bandwidth_up;
};
-/**
- * struct batadv_tvlv_tt_data - tt data propagated through the tt tvlv container
- * @flags: translation table flags (see batadv_tt_data_flags)
- * @ttvn: translation table version number
- * @num_vlan: number of announced VLANs. In the TVLV this struct is followed by
- * one batadv_tvlv_tt_vlan_data object per announced vlan
- */
-struct batadv_tvlv_tt_data {
- __u8 flags;
- __u8 ttvn;
- __be16 num_vlan;
-};
-
/**
* struct batadv_tvlv_tt_vlan_data - vlan specific tt data propagated through
* the tt tvlv container
@@ -618,6 +605,21 @@ struct batadv_tvlv_tt_vlan_data {
__u16 reserved;
};
+/**
+ * struct batadv_tvlv_tt_data - tt data propagated through the tt tvlv container
+ * @flags: translation table flags (see batadv_tt_data_flags)
+ * @ttvn: translation table version number
+ * @num_vlan: number of announced VLANs. In the TVLV this struct is followed by
+ * one batadv_tvlv_tt_vlan_data object per announced vlan
+ * @vlan_data: array of batadv_tvlv_tt_vlan_data objects
+ */
+struct batadv_tvlv_tt_data {
+ __u8 flags;
+ __u8 ttvn;
+ __be16 num_vlan;
+ struct batadv_tvlv_tt_vlan_data vlan_data[];
+};
+
/**
* struct batadv_tvlv_tt_change - translation table diff data
* @flags: status indicators concerning the non-mesh client (see
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c
index b95c36765d04..96d22d8209f4 100644
--- a/net/batman-adv/translation-table.c
+++ b/net/batman-adv/translation-table.c
@@ -856,8 +856,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node *orig_node,
num_entries += atomic_read(&vlan->tt.num_entries);
}
- change_offset = sizeof(**tt_data);
- change_offset += num_vlan * sizeof(*tt_vlan);
+ change_offset = struct_size(*tt_data, vlan_data, num_vlan);
/* if tt_len is negative, allocate the space needed by the full table */
if (*tt_len < 0)
@@ -876,7 +875,7 @@ batadv_tt_prepare_tvlv_global_data(struct batadv_orig_node *orig_node,
(*tt_data)->ttvn = atomic_read(&orig_node->last_ttvn);
(*tt_data)->num_vlan = htons(num_vlan);
- tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
+ tt_vlan = (*tt_data)->vlan_data;
hlist_for_each_entry(vlan, &orig_node->vlan_list, list) {
tt_vlan->vid = htons(vlan->vid);
tt_vlan->crc = htonl(vlan->tt.crc);
@@ -936,8 +935,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv,
total_entries += vlan_entries;
}
- change_offset = sizeof(**tt_data);
- change_offset += num_vlan * sizeof(*tt_vlan);
+ change_offset = struct_size(*tt_data, vlan_data, num_vlan);
/* if tt_len is negative, allocate the space needed by the full table */
if (*tt_len < 0)
@@ -956,7 +954,7 @@ batadv_tt_prepare_tvlv_local_data(struct batadv_priv *bat_priv,
(*tt_data)->ttvn = atomic_read(&bat_priv->tt.vn);
(*tt_data)->num_vlan = htons(num_vlan);
- tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(*tt_data + 1);
+ tt_vlan = (*tt_data)->vlan_data;
hlist_for_each_entry(vlan, &bat_priv->softif_vlan_list, list) {
vlan_entries = atomic_read(&vlan->tt.num_entries);
if (vlan_entries < 1)
@@ -2916,7 +2914,6 @@ static bool batadv_send_tt_request(struct batadv_priv *bat_priv,
{
struct batadv_tvlv_tt_data *tvlv_tt_data = NULL;
struct batadv_tt_req_node *tt_req_node = NULL;
- struct batadv_tvlv_tt_vlan_data *tt_vlan_req;
struct batadv_hard_iface *primary_if;
bool ret = false;
int i, size;
@@ -2932,7 +2929,7 @@ static bool batadv_send_tt_request(struct batadv_priv *bat_priv,
if (!tt_req_node)
goto out;
- size = sizeof(*tvlv_tt_data) + sizeof(*tt_vlan_req) * num_vlan;
+ size = struct_size(tvlv_tt_data, vlan_data, num_vlan);
tvlv_tt_data = kzalloc(size, GFP_ATOMIC);
if (!tvlv_tt_data)
goto out;
@@ -2944,12 +2941,10 @@ static bool batadv_send_tt_request(struct batadv_priv *bat_priv,
/* send all the CRCs within the request. This is needed by intermediate
* nodes to ensure they have the correct table before replying
*/
- tt_vlan_req = (struct batadv_tvlv_tt_vlan_data *)(tvlv_tt_data + 1);
for (i = 0; i < num_vlan; i++) {
- tt_vlan_req->vid = tt_vlan->vid;
- tt_vlan_req->crc = tt_vlan->crc;
+ tvlv_tt_data->vlan_data[i].vid = tt_vlan->vid;
+ tvlv_tt_data->vlan_data[i].crc = tt_vlan->crc;
- tt_vlan_req++;
tt_vlan++;
}
@@ -3001,7 +2996,6 @@ static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv,
struct batadv_orig_node *res_dst_orig_node = NULL;
struct batadv_tvlv_tt_change *tt_change;
struct batadv_tvlv_tt_data *tvlv_tt_data = NULL;
- struct batadv_tvlv_tt_vlan_data *tt_vlan;
bool ret = false, full_table;
u8 orig_ttvn, req_ttvn;
u16 tvlv_len;
@@ -3024,10 +3018,9 @@ static bool batadv_send_other_tt_response(struct batadv_priv *bat_priv,
orig_ttvn = (u8)atomic_read(&req_dst_orig_node->last_ttvn);
req_ttvn = tt_data->ttvn;
- tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(tt_data + 1);
/* this node doesn't have the requested data */
if (orig_ttvn != req_ttvn ||
- !batadv_tt_global_check_crc(req_dst_orig_node, tt_vlan,
+ !batadv_tt_global_check_crc(req_dst_orig_node, tt_data->vlan_data,
ntohs(tt_data->num_vlan)))
goto out;
@@ -3370,7 +3363,6 @@ static void batadv_handle_tt_response(struct batadv_priv *bat_priv,
struct batadv_orig_node *orig_node = NULL;
struct batadv_tvlv_tt_change *tt_change;
u8 *tvlv_ptr = (u8 *)tt_data;
- u16 change_offset;
batadv_dbg(BATADV_DBG_TT, bat_priv,
"Received TT_RESPONSE from %pM for ttvn %d t_size: %d [%c]\n",
@@ -3383,10 +3375,7 @@ static void batadv_handle_tt_response(struct batadv_priv *bat_priv,
spin_lock_bh(&orig_node->tt_lock);
- change_offset = sizeof(struct batadv_tvlv_tt_vlan_data);
- change_offset *= ntohs(tt_data->num_vlan);
- change_offset += sizeof(*tt_data);
- tvlv_ptr += change_offset;
+ tvlv_ptr += struct_size(tt_data, vlan_data, ntohs(tt_data->num_vlan));
tt_change = (struct batadv_tvlv_tt_change *)tvlv_ptr;
if (tt_data->flags & BATADV_TT_FULL_TABLE) {
@@ -3985,10 +3974,10 @@ static void batadv_tt_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
u8 flags, void *tvlv_value,
u16 tvlv_value_len)
{
- struct batadv_tvlv_tt_vlan_data *tt_vlan;
struct batadv_tvlv_tt_change *tt_change;
struct batadv_tvlv_tt_data *tt_data;
u16 num_entries, num_vlan;
+ size_t flex_size;
if (tvlv_value_len < sizeof(*tt_data))
return;
@@ -3998,17 +3987,18 @@ static void batadv_tt_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv,
num_vlan = ntohs(tt_data->num_vlan);
- if (tvlv_value_len < sizeof(*tt_vlan) * num_vlan)
+ flex_size = flex_array_size(tt_data, vlan_data, num_vlan);
+ if (tvlv_value_len < flex_size)
return;
- tt_vlan = (struct batadv_tvlv_tt_vlan_data *)(tt_data + 1);
- tt_change = (struct batadv_tvlv_tt_change *)(tt_vlan + num_vlan);
- tvlv_value_len -= sizeof(*tt_vlan) * num_vlan;
+ tt_change = (struct batadv_tvlv_tt_change *)(tt_data->vlan_data +
+ num_vlan);
+ tvlv_value_len -= flex_size;
num_entries = batadv_tt_entries(tvlv_value_len);
- batadv_tt_update_orig(bat_priv, orig, tt_vlan, num_vlan, tt_change,
- num_entries, tt_data->ttvn);
+ batadv_tt_update_orig(bat_priv, orig, tt_data->vlan_data, num_vlan,
+ tt_change, num_entries, tt_data->ttvn);
}
/**
@@ -4039,8 +4029,7 @@ static int batadv_tt_tvlv_unicast_handler_v1(struct batadv_priv *bat_priv,
tt_data = tvlv_value;
tvlv_value_len -= sizeof(*tt_data);
- tt_vlan_len = sizeof(struct batadv_tvlv_tt_vlan_data);
- tt_vlan_len *= ntohs(tt_data->num_vlan);
+ tt_vlan_len = flex_array_size(tt_data, vlan_data, tt_data->num_vlan);
if (tvlv_value_len < tt_vlan_len)
return NET_RX_SUCCESS;
--
2.25.1
next reply other threads:[~2024-04-02 17:23 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-02 17:23 Erick Archer [this message]
2024-04-02 19:06 ` [PATCH] batman-adv: Add flex array to struct batadv_tvlv_tt_data Sven Eckelmann
2024-04-06 16:46 ` Erick Archer
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