| Message ID | 20200916140535.1451663-1-philmd@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series | hw/nvram/fw_cfg: Assert linked data is not NULL | expand |
Hi Phil, On 09/16/20 16:05, Philippe Mathieu-Daudé wrote: > The linked data passed to the fw_cfg device must not be NULL. > Add an assertion. > > Reported-by: Laszlo Ersek <lersek@redhat.com> > Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> > --- > hw/nvram/fw_cfg.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c > index f3a4728288e..40dcc08b57b 100644 > --- a/hw/nvram/fw_cfg.c > +++ b/hw/nvram/fw_cfg.c > @@ -711,6 +711,7 @@ static void fw_cfg_add_bytes_callback(FWCfgState *s, uint16_t key, > > key &= FW_CFG_ENTRY_MASK; > > + assert(data); > assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX); > assert(s->entries[arch][key].data == NULL); /* avoid key conflict */ > > (1) this assert() would fire without my [PATCH] hw/nvram/fw_cfg: fix FWCfgDataGeneratorClass::get_data() consumption so minimally we should apply your patch only after mine. (2) I'm unsure if it's *always* a programming error to link a NULL datum under an fw_cfg key. The reader functions fw_cfg_data_read() and fw_cfg_dma_transfer() deal with NULL data gracefully. I think we should add the assert() only if we can prove that "include/hw/nvram/fw_cfg.h" already forbids callers from passing in NULL data. Otherwise, we'll have to audit all the fw-cfg-add-xxx call sites, extend the comments in the header file, and *then* add the assert(). For now I'd only go with the patch I posted. Thanks! Laszlo
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index f3a4728288e..40dcc08b57b 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -711,6 +711,7 @@ static void fw_cfg_add_bytes_callback(FWCfgState *s, uint16_t key, key &= FW_CFG_ENTRY_MASK; + assert(data); assert(key < fw_cfg_max_entry(s) && len < UINT32_MAX); assert(s->entries[arch][key].data == NULL); /* avoid key conflict */
The linked data passed to the fw_cfg device must not be NULL. Add an assertion. Reported-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com> --- hw/nvram/fw_cfg.c | 1 + 1 file changed, 1 insertion(+)