mlxfw: fix null-ptr-deref in mlxfw_mfa2_tlv_next()

Function mlxfw_mfa2_tlv_multi_get() returns NULL if 'tlv' in
question does not pass checks in mlxfw_mfa2_tlv_payload_get(). This
behaviour may lead to NULL pointer dereference in 'multi->total_len'.
Fix this issue by testing mlxfw_mfa2_tlv_multi_get()'s return value
against NULL.

Found by Linux Verification Center (linuxtesting.org) with static
analysis tool SVACE.

Fixes: 410ed13cae39 ("Add the mlxfw module for Mellanox firmware flash process")
Co-developed-by: Natalia Petrova <n.petrova@fintech.ru>
Signed-off-by: Nikita Zhandarovich <n.zhandarovich@fintech.ru>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://lore.kernel.org/r/20230417120718.52325-1-n.zhandarovich@fintech.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv_multi.c b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv_multi.c
index 017d68f1e1232c394aa4b2ac209300256fbbab51..972c571b41587a14518b71d8bacce2172f82a081 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv_multi.c
+++ b/drivers/net/ethernet/mellanox/mlxfw/mlxfw_mfa2_tlv_multi.c
@@ -31,6 +31,8 @@ mlxfw_mfa2_tlv_next(const struct mlxfw_mfa2_file *mfa2_file,
 
        if (tlv->type == MLXFW_MFA2_TLV_MULTI_PART) {
                multi = mlxfw_mfa2_tlv_multi_get(mfa2_file, tlv);
+               if (!multi)
+                       return NULL;
                tlv_len = NLA_ALIGN(tlv_len + be16_to_cpu(multi->total_len));
        }