efi_loader: fix handling of DHCP acknowledge

The dhcp command may be executed after the first UEFI command.
We should still update the EFI_PXE_BASE_CODE_PROTOCOL.

Don't leak content of prior acknowledge packages.

Handle failing allocation when calling malloc().

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

diff --git a/lib/efi_loader/efi_net.c b/lib/efi_loader/efi_net.c
index 69276b2..96a5bcc 100644 (file)
--- a/lib/efi_loader/efi_net.c
+++ b/lib/efi_loader/efi_net.c
@@ -30,6 +30,7 @@ static uchar **receive_buffer;
 static size_t *receive_lengths;
 static int rx_packet_idx;
 static int rx_packet_num;
+static struct efi_net_obj *netobj;
 
 /*
  * The notification function of this event is called in every timer cycle
@@ -660,10 +661,16 @@ void efi_net_set_dhcp_ack(void *pkt, int len)
 {
        int maxsize = sizeof(*dhcp_ack);
 
-       if (!dhcp_ack)
+       if (!dhcp_ack) {
                dhcp_ack = malloc(maxsize);
-
+               if (!dhcp_ack)
+                       return;
+       }
+       memset(dhcp_ack, 0, maxsize);
        memcpy(dhcp_ack, pkt, min(len, maxsize));
+
+       if (netobj)
+               netobj->pxe_mode.dhcp_ack = *dhcp_ack;
 }
 
 /**
@@ -853,7 +860,6 @@ static efi_status_t EFIAPI efi_pxe_base_code_set_packets(
  */
 efi_status_t efi_net_register(void)
 {
-       struct efi_net_obj *netobj = NULL;
        efi_status_t r;
        int i;
 
@@ -982,6 +988,7 @@ failure_to_add_protocol:
        return r;
 out_of_resources:
        free(netobj);
+       netobj = NULL;
        free(transmit_buffer);
        if (receive_buffer)
                for (i = 0; i < ETH_PACKETS_BATCH_RECV; i++)