On Tue, Feb 12, 2019 at 05:46:57PM +0000, Andre Przywara wrote:
> From: Andrei Borzenkov <arvidj...@gmail.com>
>
> The BOOTP RFC describes the boot file name and the server name as being
> part of the integral BOOTP data structure, with some limits on the size
> of them.
> DHCP extends this by allowing them to be separate DHCP options, which is
> more flexible.
>
> Teach the code dealing with those fields to check for those DHCP options
> first and use this information, if provided. We fall back to using the
> BOOTP information if those options are not used.
>
> Signed-off-by: Andre Przywara <andre.przyw...@arm.com>
> ---
> grub-core/net/bootp.c | 72 +++++++++++++++++++++++++++++++------------
> include/grub/net.h | 2 ++
> 2 files changed, 54 insertions(+), 20 deletions(-)
>
> diff --git a/grub-core/net/bootp.c b/grub-core/net/bootp.c
> index 42117b72d..0c6756ea0 100644
> --- a/grub-core/net/bootp.c
> +++ b/grub-core/net/bootp.c
> @@ -169,7 +169,9 @@ grub_net_configure_by_dhcp_ack (const char *name,
> int mask = -1;
> char server_ip[sizeof ("xxx.xxx.xxx.xxx")];
> const grub_uint8_t *opt;
> - grub_uint8_t opt_len;
> + grub_uint8_t opt_len, overload = 0;
> + const char *boot_file = 0, *server_name = 0;
> + grub_size_t boot_file_len, server_name_len;
>
> addr.type = GRUB_NET_NETWORK_LEVEL_PROTOCOL_IPV4;
> addr.ipv4 = bp->your_ip;
> @@ -188,9 +190,36 @@ grub_net_configure_by_dhcp_ack (const char *name,
> if (!inter)
> return 0;
>
> - if (size > OFFSET_OF (boot_file, bp))
> - grub_env_set_net_property (name, "boot_file", bp->boot_file,
> - sizeof (bp->boot_file));
> + opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_OVERLOAD, &opt_len);
> + if (opt && opt_len == 1)
> + overload = *opt;
> +
> + opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_TFTP_SERVER_NAME,
> &opt_len);
> + if (opt && opt_len)
> + {
> + server_name = (const char *) opt;
> + server_name_len = opt_len;
> + }
> + else if (size > OFFSET_OF (server_name, bp) && !(overload &
> GRUB_DHCP_OPT_OVERLOAD_SNAME) &&
> + bp->server_name[0])
> + {
> + server_name = bp->server_name;
> + server_name_len = sizeof (bp->server_name);
> + }
> +
> + opt = find_dhcp_option (bp, size, GRUB_NET_DHCP_BOOTFILE_NAME, &opt_len);
> + if (opt && opt_len)
> + {
> + boot_file = (const char *) opt;
> + boot_file_len = opt_len;
> + }
> + else if (size > OFFSET_OF (boot_file, bp) && !(overload &&
> GRUB_DHCP_OPT_OVERLOAD_FILE) &&
> + bp->boot_file[0])
> + {
> + boot_file = bp->boot_file;
> + boot_file_len = sizeof (bp->boot_file);
> + }
> +
> if (bp->server_ip)
> {
> grub_snprintf (server_ip, sizeof (server_ip), "%d.%d.%d.%d",
> @@ -221,35 +250,38 @@ grub_net_configure_by_dhcp_ack (const char *name,
> *device = grub_xasprintf ("tftp,%s", server_ip);
> grub_print_error ();
> }
> - if (size > OFFSET_OF (server_name, bp)
> - && bp->server_name[0])
> +
> + if (server_name)
> {
> - grub_env_set_net_property (name, "dhcp_server_name", bp->server_name,
> - sizeof (bp->server_name));
> + grub_env_set_net_property (name, "dhcp_server_name", server_name,
> server_name_len);
> if (is_def && !grub_net_default_server)
> {
> - grub_net_default_server = grub_strdup (bp->server_name);
> + grub_net_default_server = grub_strdup (server_name);
> grub_print_error ();
> }
> if (device && !*device)
> {
> - *device = grub_xasprintf ("tftp,%s", bp->server_name);
> + *device = grub_xasprintf ("tftp,%s", server_name);
> grub_print_error ();
> }
> }
>
> - if (size > OFFSET_OF (boot_file, bp) && path)
> + if (boot_file)
> {
> - *path = grub_strndup (bp->boot_file, sizeof (bp->boot_file));
> - grub_print_error ();
> - if (*path)
> + grub_env_set_net_property (name, "boot_file", boot_file,
> boot_file_len);
> + if (path)
> {
> - char *slash;
> - slash = grub_strrchr (*path, '/');
> - if (slash)
> - *slash = 0;
> - else
> - **path = 0;
> + *path = grub_strndup (boot_file, boot_file_len);
> + grub_print_error ();
> + if (*path)
> + {
> + char *slash;
> + slash = grub_strrchr (*path, '/');
> + if (slash)
> + *slash = 0;
> + else
> + **path = 0;
> + }
I am not sure why you are changing the code starting from
"if (size > OFFSET_OF (boot_file, bp) && path)". Could you
enlighten me?
Daniel
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