Re: [Qemu-devel] [PULL 02/21] roms: assert if max rom size is less than the used size

[Thomas Huth]

On 15/05/2019 22.50, Paolo Bonzini wrote:
> From: Igor Mammedov 
> 
> It would ensure that we would notice attempt to write beyond
> the allocated buffer. In case of MemoryRegion backed ROM it's
> the host buffer and the guest RAM otherwise.
> 
> assert can be triggered with:
>   dd if=/dev/zero of=/tmp/blob bs=63k count=1
>   qemu-system-x86_64 `for  i in {1..33}; do echo -n " -acpitable /tmp/blob"; 
> done`

Sorry, but a user should normally never be able to trigger an assert,
even if passing lots of garbage to qemu via the command line. asserts
are for guarding against programming errors.

Could you please change this into a proper error message instead?

 Thanks,
  Thomas

[Qemu-devel] [PULL 02/21] roms: assert if max rom size is less than the used size

[Paolo Bonzini]

From: Igor Mammedov 

It would ensure that we would notice attempt to write beyond
the allocated buffer. In case of MemoryRegion backed ROM it's
the host buffer and the guest RAM otherwise.

assert can be triggered with:
  dd if=/dev/zero of=/tmp/blob bs=63k count=1
  qemu-system-x86_64 `for  i in {1..33}; do echo -n " -acpitable /tmp/blob"; 
done`

Fixes: (a1666142db acpi-build: make ROMs RAM blocks resizeable)

Reported-by: Wei Yang 
Signed-off-by: Igor Mammedov 
Message-Id: <1554982098-336210-1-git-send-email-imamm...@redhat.com>
Signed-off-by: Paolo Bonzini 
---
 hw/core/loader.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/core/loader.c b/hw/core/loader.c
index fe5cb24..a097bbe 100644
--- a/hw/core/loader.c
+++ b/hw/core/loader.c
@@ -1025,6 +1025,7 @@ MemoryRegion *rom_add_blob(const char *name, const void 
*blob, size_t len,
 rom->addr = addr;
 rom->romsize  = max_len ? max_len : len;
 rom->datasize = len;
+g_assert(rom->romsize >= rom->datasize);
 rom->data = g_malloc0(rom->datasize);
 memcpy(rom->data, blob, len);
 rom_insert(rom);
-- 
1.8.3.1