[PATCH v2 1/6] net: wget: prevent overwriting reserved memory

[Masahisa Kojima]

Hi Simon,

On Sat, 2 Sept 2023 at 09:09, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Masahisa,
>
> On Fri, 1 Sept 2023 at 04:26, Masahisa Kojima
> <masahisa.kojima at linaro.org> wrote:
> >
> > This introduces the valid range check to store the received
> > blocks using lmb. The same logic is implemented in tftp.
> >
> > Signed-off-by: Masahisa Kojima <masahisa.kojima at linaro.org>
> > ---
> >  net/wget.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 69 insertions(+), 7 deletions(-)
> >
> > diff --git a/net/wget.c b/net/wget.c
> > index 2dbfeb1a1d..8bf4db4d04 100644
> > --- a/net/wget.c
> > +++ b/net/wget.c
> > @@ -4,16 +4,20 @@
> >   * Copyright Duncan Hare <dh at synoia.com> 2017
> >   */
> >
> > +#include <asm/global_data.h>
> >  #include <command.h>
> >  #include <common.h>
> >  #include <display_options.h>
> >  #include <env.h>
> >  #include <image.h>
> > +#include <lmb.h>
> >  #include <mapmem.h>
> >  #include <net.h>
> >  #include <net/tcp.h>
> >  #include <net/wget.h>
> >
> > +DECLARE_GLOBAL_DATA_PTR;
> > +
> >  static const char bootfile1[] = "GET ";
> >  static const char bootfile3[] = " HTTP/1.0\r\n\r\n";
> >  static const char http_eom[] = "\r\n\r\n";
> > @@ -55,6 +59,32 @@ static unsigned int retry_tcp_ack_num;       /* TCP retry acknowledge number*/
> >  static unsigned int retry_tcp_seq_num; /* TCP retry sequence number */
> >  static int retry_len;                  /* TCP retry length */
> >
> > +#ifdef CONFIG_LMB
> > +static ulong wget_load_size;
> > +#endif
> > +
> > +/**
> > + * wget_init_max_size() - initialize maximum load size
> > + *
> > + * Return:     0 if success, -1 if fails
> > + */
> > +static int wget_init_load_size(void)
> > +{
> > +#ifdef CONFIG_LMB
>
> please can you use if IS_ENABLED() throughout?
OK.

>
> > +       struct lmb lmb;
> > +       phys_size_t max_size;
> > +
> > +       lmb_init_and_reserve(&lmb, gd->bd, (void *)gd->fdt_blob);
> > +
> > +       max_size = lmb_get_free_size(&lmb, image_load_addr);
> > +       if (!max_size)
> > +               return -1;
> > +
> > +       wget_load_size = max_size;
> > +#endif
> > +       return 0;
> > +}
> > +
> >  /**
> >   * store_block() - store block in memory
> >   * @src: source of data
> > @@ -63,10 +93,24 @@ static int retry_len;                       /* TCP retry length */
> >   */
> >  static inline int store_block(uchar *src, unsigned int offset, unsigned int len)
> >  {
> > +       ulong store_addr = image_load_addr + offset;
> >         ulong newsize = offset + len;
> >         uchar *ptr;
> >
> > -       ptr = map_sysmem(image_load_addr + offset, len);
> > +#ifdef CONFIG_LMB
> > +       ulong end_addr = image_load_addr + wget_load_size;
> > +
> > +       if (!end_addr)
> > +               end_addr = ULONG_MAX;
> > +
> > +       if (store_addr < image_load_addr ||
> > +               store_addr + len > end_addr) {
> > +               puts("\nwget error: ");
> > +               puts("trying to overwrite reserved memory...\n");
> > +               return -1;
> > +       }
> > +#endif
> > +       ptr = map_sysmem(store_addr, len);
> >         memcpy(ptr, src, len);
> >         unmap_sysmem(ptr);
> >
> > @@ -240,25 +284,37 @@ static void wget_connected(uchar *pkt, unsigned int tcp_seq_num,
> >
> >                         net_boot_file_size = 0;
> >
> > -                       if (len > hlen)
> > -                               store_block(pkt + hlen, 0, len - hlen);
> > +                       if (len > hlen) {
> > +                               if (store_block(pkt + hlen, 0, len - hlen) != 0) {
> > +                                       wget_loop_state = NETLOOP_FAIL;
> > +                                       wget_fail("wget: store error\n", tcp_seq_num, tcp_ack_num, action);
> > +                                       return;
> > +                               }
> > +                       }
> >
> >                         debug_cond(DEBUG_WGET,
> >                                    "wget: Connected Pkt %p hlen %x\n",
> >                                    pkt, hlen);
> >
> >                         for (i = 0; i < pkt_q_idx; i++) {
> > +                               int err;
> > +
> >                                 ptr1 = map_sysmem(
> >                                         (phys_addr_t)(pkt_q[i].pkt),
> >                                         pkt_q[i].len);
> > -                               store_block(ptr1,
> > -                                           pkt_q[i].tcp_seq_num -
> > -                                           initial_data_seq_num,
> > -                                           pkt_q[i].len);
> > +                               err = store_block(ptr1,
> > +                                                 pkt_q[i].tcp_seq_num -
> > +                                                 initial_data_seq_num,
> > +                                                 pkt_q[i].len);
> >                                 unmap_sysmem(ptr1);
> >                                 debug_cond(DEBUG_WGET,
> >                                            "wget: Connctd pkt Q %p len %x\n",
> >                                            pkt_q[i].pkt, pkt_q[i].len);
> > +                               if (err) {
> > +                                       wget_loop_state = NETLOOP_FAIL;
> > +                                       wget_fail("wget: store error\n", tcp_seq_num, tcp_ack_num, action);
> > +                                       return;
> > +                               }
> >                         }
> >                 }
> >         }
> > @@ -420,6 +476,12 @@ void wget_start(void)
> >         debug_cond(DEBUG_WGET,
> >                    "\nwget:Load address: 0x%lx\nLoading: *\b", image_load_addr);
> >
> > +       if (wget_init_load_size()) {
> > +               puts("\nwget error: ");
> > +               puts("trying to overwrite reserved memory...\n");
>
> I think it is OK to use printf() here.
OK.

>
> > +               return;
>
> Needs to return the error code

I will modify it to notify the caller of the  error by calling
"net_set_state(NETLOOP_FAIL);"
instead of returning the error code.

Thanks,
Masahisa Kojima

>
> > +       }
> > +
> >         net_set_timeout_handler(wget_timeout, wget_timeout_handler);
> >         tcp_set_tcp_handler(wget_handler);
> >
> > --
> > 2.34.1
> >
>
> Regards,
> Simon