Re: [PATCH] net: eepro100: validate various address values

[Stefan Weil <sw@weilnetz.de>]

Am 19.02.21 um 10:26 schrieb P J P:

>    Hello Stefan,
>
> +-- On Fri, 19 Feb 2021, Stefan Weil wrote --+
> | If there are no recursions in normal use, the following patch should work:
> |
> | diff --git a/hw/net/eepro100.c b/hw/net/eepro100.c
> | index 16e95ef9cc..2474cf3dc2 100644
> | --- a/hw/net/eepro100.c
> | +++ b/hw/net/eepro100.c
> | @@ -279,6 +279,9 @@ typedef struct {
> |      /* Quasi static device properties (no need to save them). */
> |      uint16_t stats_size;
> |      bool has_extended_tcb_support;
> | +
> | +    /* Flag to avoid recursions. */
> | +    bool busy;
> |  } EEPRO100State;
> |
> |  /* Word indices in EEPROM. */
> | @@ -837,6 +840,14 @@ static void action_command(EEPRO100State *s)
> |         Therefore we limit the number of iterations. */
> |      unsigned max_loop_count = 16;
> |
> | +    if (s->busy) {
> | +        /* Prevent recursions. */
> | +        logout("recursion in %s:%u\n", __FILE__, __LINE__);
> | +        return;
> | +    }
> | +
> | +    s->busy = true;
> | +
> |      for (;;) {
> |          bool bit_el;
> |          bool bit_s;
> | @@ -933,6 +944,7 @@ static void action_command(EEPRO100State *s)
> |      }
> |      TRACE(OTHER, logout("CU list empty\n"));
> |      /* List is empty. Now CU is idle or suspended. */
> | +    s->busy = false;
> |  }
> |
> |  static void eepro100_cu_command(EEPRO100State * s, uint8_t val)
>
> Please see:
>    -> https://ruhr-uni-bochum.sciebo.de/s/NNWP2GfwzYKeKwE?path=%2Feepro100_stackoverflow1
>
> * It does not seem to address above case.


My suggested patch fixes that test case: it no longer crashes because of 
an endless recursion.

Stefan