[PATCH 4/6] net: lwip: Enable https:// support for wget

Ilias Apalodimas ilias.apalodimas at linaro.org
Mon Oct 21 13:00:11 CEST 2024


Hi Simon,

On Sat, 19 Oct 2024 at 14:50, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Ilias,
>
> On Fri, 18 Oct 2024 at 08:23, Ilias Apalodimas
> <ilias.apalodimas at linaro.org> wrote:
> >
> > With the recent changes of lwip & mbedTLS we can now download from
> > https:// urls instead of just http://.
> > Adjust our wget lwip version parsing to support both URLs.
> > While at it adjust the default TCP window for QEMU since https seems to
> > requite at least 16384
> >
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > ---
> >  cmd/Kconfig      | 19 ++++++++++++
> >  net/lwip/Kconfig |  2 +-
> >  net/lwip/wget.c  | 78 +++++++++++++++++++++++++++++++++++++++++++-----
> >  3 files changed, 91 insertions(+), 8 deletions(-)
> >
> > diff --git a/cmd/Kconfig b/cmd/Kconfig
> > index 8c677b1e4864..e58566a9ba34 100644
> > --- a/cmd/Kconfig
> > +++ b/cmd/Kconfig
> > @@ -2118,6 +2118,25 @@ config CMD_WGET
> >           wget is a simple command to download kernel, or other files,
> >           from a http server over TCP.
> >
> > +config WGET_HTTPS
> > +       bool "wget https"
> > +       depends on CMD_WGET
>
> Is it possible to do wget programmatically, i.e. without CMDLINE?

Yes. But that would require more untangling of wget. I'll look into
that once we are done with features.

>
> > +       depends on PROT_TCP_LWIP
> > +       depends on MBEDTLS_LIB
> > +        select SHA256
> > +        select RSA
> > +        select ASYMMETRIC_KEY_TYPE
> > +        select ASYMMETRIC_PUBLIC_KEY_SUBTYPE
> > +        select X509_CERTIFICATE_PARSER
> > +        select PKCS7_MESSAGE_PARSER
> > +       select MBEDTLS_LIB_CRYPTO
> > +       select MBEDTLS_LIB_TLS
> > +       select RSA_VERIFY_WITH_PKEY
> > +       select X509_CERTIFICATE_PARSER
> > +       select PKCS7_MESSAGE_PARSER
> > +       help
> > +         Enable TLS over http for wget.
> > +
> >  endif  # if CMD_NET
> >
> >  config CMD_PXE
> > diff --git a/net/lwip/Kconfig b/net/lwip/Kconfig
> > index 8a67de4cf335..a9ae9bf7fa2a 100644
> > --- a/net/lwip/Kconfig
> > +++ b/net/lwip/Kconfig
> > @@ -37,7 +37,7 @@ config PROT_UDP_LWIP
> >
> >  config LWIP_TCP_WND
> >         int "Value of TCP_WND"
> > -       default 8000 if ARCH_QEMU
> > +       default 32768 if ARCH_QEMU
> >         default 3000000
> >         help
> >           Default value for TCP_WND in the lwIP configuration
> > diff --git a/net/lwip/wget.c b/net/lwip/wget.c
> > index b495ebd1aa96..b4f039d38962 100644
> > --- a/net/lwip/wget.c
> > +++ b/net/lwip/wget.c
> > @@ -7,13 +7,17 @@
> >  #include <efi_loader.h>
> >  #include <image.h>
> >  #include <lwip/apps/http_client.h>
> > +#include "lwip/altcp_tls.h"
> >  #include <lwip/timeouts.h>
> > +#include <rng.h>
> >  #include <mapmem.h>
> >  #include <net.h>
> >  #include <time.h>
> > +#include <dm/uclass.h>
> >
> >  #define SERVER_NAME_SIZE 200
> >  #define HTTP_PORT_DEFAULT 80
> > +#define HTTPS_PORT_DEFAULT 443
> >  #define PROGRESS_PRINT_STEP_BYTES (100 * 1024)
> >
> >  enum done_state {
> > @@ -32,18 +36,53 @@ struct wget_ctx {
> >         enum done_state done;
> >  };
> >
> > +bool wget_validate_uri(char *uri);
> > +
> > +int mbedtls_hardware_poll(void *data, unsigned char *output, size_t len,
> > +                         size_t *olen)
> > +{
> > +       struct udevice *dev;
> > +       u64 rng = 0;
> > +       int err;
>
> ret
>
> > +
> > +       *olen = 0;
> > +
> > +       err = uclass_get_device(UCLASS_RNG, 0, &dev);
>
> Using uclass_get_device_by_seq() would allow aliases to select which
> device is used.

Ok, but I don't think we need it here. We just need a random number
from any device that can send us one no?

>
> > +       if (err)
> > +               return err;
> > +       err = dm_rng_read(dev, &rng, sizeof(rng));
> > +       if (err) {
> > +               log_err("Failed to get an rng: %d\n", err);
>
> If you are showing an error, I think it is more likely to happen when
> trying to find the device, so perhaps do this on the
> uclass_get_device() call?

Sure

>
> > +               return err;
> > +       }
> > +
> > +       memcpy(output, &rng, len);
> > +       *olen = sizeof(rng);
>
> But then why not dm_rng_read() into output and avoid the u64?
> Actually, dm_rng_ops-read() should return the number of bytes,
> perhaps?

The caller defines the length. Copying blindly a u64 might overflow.
But the current code should be
*olen = len

>
> > +
> > +       return 0;
> > +}
> > +
> >  static int parse_url(char *url, char *host, u16 *port, char **path)
> >  {
> >         char *p, *pp;
> >         long lport;
> > +       size_t prefix_len = 0;
> > +
> > +       if (!wget_validate_uri(url)) {
> > +               log_err("Invalid URL. Use http(s)://\n");
> > +               return -EINVAL;
> > +       }
> >
> > +       *port = HTTP_PORT_DEFAULT;
> > +       prefix_len = strlen("http://");
> >         p = strstr(url, "http://");
> >         if (!p) {
> > -               log_err("only http:// is supported\n");
> > -               return -EINVAL;
> > +               p = strstr(url, "https://");
> > +               prefix_len = strlen("https://");
> > +               *port = HTTPS_PORT_DEFAULT;
> >         }
> >
> > -       p += strlen("http://");
> > +       p += prefix_len;
> >
> >         /* Parse hostname */
> >         pp = strchr(p, ':');
> > @@ -67,9 +106,8 @@ static int parse_url(char *url, char *host, u16 *port, char **path)
> >                 if (lport > 65535)
> >                         return -EINVAL;
> >                 *port = (u16)lport;
> > -       } else {
> > -               *port = HTTP_PORT_DEFAULT;
> >         }
> > +
> >         if (*pp != '/')
> >                 return -EINVAL;
> >         *path = pp;
> > @@ -210,6 +248,9 @@ static void httpc_result_cb(void *arg, httpc_result_t httpc_result,
> >  static int wget_loop(struct udevice *udev, ulong dst_addr, char *uri)
> >  {
> >         char server_name[SERVER_NAME_SIZE];
> > +#if defined CONFIG_WGET_HTTPS
> > +       altcp_allocator_t tls_allocator;
> > +#endif
> >         httpc_connection_t conn;
> >         httpc_state_t *state;
> >         struct netif *netif;
> > @@ -232,6 +273,22 @@ static int wget_loop(struct udevice *udev, ulong dst_addr, char *uri)
> >                 return -1;
> >
> >         memset(&conn, 0, sizeof(conn));
> > +#if defined CONFIG_WGET_HTTPS
>
> if (IS_ENABLED(CONFIG_WGET_HTTPS))
>

Unfortunately, I don't think we can use that here. If
CONFIG_WGET_HTTPS is not enabled LWIP_ALTCP will not be defined, and
the altcp_allocator_t field will be missing from the struct leading to
a compilation error

Thanks
/Ilias

> > +       if (port == HTTPS_PORT_DEFAULT) {
> > +               tls_allocator.alloc = &altcp_tls_alloc;
> > +               tls_allocator.arg =
> > +                       altcp_tls_create_config_client(NULL, 0, server_name);
> > +
> > +               if (!tls_allocator.arg) {
> > +                       log_err("error: Cannot create a TLS connection\n");
> > +                       net_lwip_remove_netif(netif);
> > +                       return -1;
> > +               }
> > +
> > +               conn.altcp_allocator = &tls_allocator;
> > +       }
> > +#endif
> > +
> >         conn.result_fn = httpc_result_cb;
> >         ctx.path = path;
> >         if (httpc_get_file_dns(server_name, port, path, &conn, httpc_recv_cb,
> > @@ -316,6 +373,7 @@ bool wget_validate_uri(char *uri)
> >         char c;
> >         bool ret = true;
> >         char *str_copy, *s, *authority;
> > +       size_t prefix_len = 0;
> >
> >         for (c = 0x1; c < 0x21; c++) {
> >                 if (strchr(uri, c)) {
> > @@ -323,15 +381,21 @@ bool wget_validate_uri(char *uri)
> >                         return false;
> >                 }
> >         }
> > +
> >         if (strchr(uri, 0x7f)) {
> >                 log_err("invalid character is used\n");
> >                 return false;
> >         }
> >
> > -       if (strncmp(uri, "http://", 7)) {
> > -               log_err("only http:// is supported\n");
> > +       if (!strncmp(uri, "http://", strlen("http://"))) {
> > +               prefix_len = strlen("http://");
> > +       } else if (!strncmp(uri, "https://", strlen("https://"))) {
> > +               prefix_len = strlen("https://");
> > +       } else {
> > +               log_err("only http(s):// is supported\n");
> >                 return false;
> >         }
> > +
> >         str_copy = strdup(uri);
> >         if (!str_copy)
> >                 return false;
> > --
> > 2.45.2
> >
>
> Regards,
> Simon


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