Re: [Qemu-devel] [PATCH] acpi: fix file size check with -acpitable.

[Blue Swirl]

Thanks, applied.

On Tue, Aug 24, 2010 at 5:06 AM, Isaku Yamahata <address@hidden> wrote:
> ping.
>
> On Thu, Jul 29, 2010 at 06:08:42PM +0900, Isaku Yamahata wrote:
>> acpi table file can be modified during load so file size check
>> should be more strict.
>> pointer calculation should be after qemu_realloc(). not before realloc().
>>
>> Signed-off-by: Isaku Yamahata <address@hidden>
>> ---
>>  hw/acpi.c |   28 +++++++++++++++++++---------
>>  1 files changed, 19 insertions(+), 9 deletions(-)
>>
>> diff --git a/hw/acpi.c b/hw/acpi.c
>> index c7044b1..069e05f 100644
>> --- a/hw/acpi.c
>> +++ b/hw/acpi.c
>> @@ -50,6 +50,8 @@ int acpi_table_add(const char *t)
>>      char buf[1024], *p, *f;
>>      struct acpi_table_header acpi_hdr;
>>      unsigned long val;
>> +    uint32_t length;
>> +    struct acpi_table_header *acpi_hdr_p;
>>      size_t off;
>>
>>      memset(&acpi_hdr, 0, sizeof(acpi_hdr));
>> @@ -108,7 +110,7 @@ int acpi_table_add(const char *t)
>>           buf[0] = '\0';
>>      }
>>
>> -    acpi_hdr.length = sizeof(acpi_hdr);
>> +    length = sizeof(acpi_hdr);
>>
>>      f = buf;
>>      while (buf[0]) {
>> @@ -120,7 +122,7 @@ int acpi_table_add(const char *t)
>>              fprintf(stderr, "Can't stat file '%s': %s\n", f, 
>> strerror(errno));
>>              goto out;
>>          }
>> -        acpi_hdr.length += s.st_size;
>> +        length += s.st_size;
>>          if (!n)
>>              break;
>>          *n = ':';
>> @@ -131,12 +133,12 @@ int acpi_table_add(const char *t)
>>          acpi_tables_len = sizeof(uint16_t);
>>          acpi_tables = qemu_mallocz(acpi_tables_len);
>>      }
>> +    acpi_tables = qemu_realloc(acpi_tables,
>> +                               acpi_tables_len + sizeof(uint16_t) + length);
>>      p = acpi_tables + acpi_tables_len;
>> -    acpi_tables_len += sizeof(uint16_t) + acpi_hdr.length;
>> -    acpi_tables = qemu_realloc(acpi_tables, acpi_tables_len);
>> +    acpi_tables_len += sizeof(uint16_t) + length;
>>
>> -    acpi_hdr.length = cpu_to_le32(acpi_hdr.length);
>> -    *(uint16_t*)p = acpi_hdr.length;
>> +    *(uint16_t*)p = cpu_to_le32(length);
>>      p += sizeof(uint16_t);
>>      memcpy(p, &acpi_hdr, sizeof(acpi_hdr));
>>      off = sizeof(acpi_hdr);
>> @@ -157,7 +159,9 @@ int acpi_table_add(const char *t)
>>              goto out;
>>          }
>>
>> -        do {
>> +        /* off < length is necessary because file size can be changed
>> +           under our foot */
>> +        while(s.st_size && off < length); {
>>              int r;
>>              r = read(fd, p + off, s.st_size);
>>              if (r > 0) {
>> @@ -167,15 +171,21 @@ int acpi_table_add(const char *t)
>>                  close(fd);
>>                  goto out;
>>              }
>> -        } while(s.st_size);
>> +        }
>>
>>          close(fd);
>>          if (!n)
>>              break;
>>          f = n + 1;
>>      }
>> +    if (off < length) {
>> +        /* don't pass random value in process to guest */
>> +        memset(p + off, 0, length - off);
>> +    }
>>
>> -    ((struct acpi_table_header*)p)->checksum = acpi_checksum((uint8_t*)p, 
>> off);
>> +    acpi_hdr_p = (struct acpi_table_header*)p;
>> +    acpi_hdr_p->length = cpu_to_le32(length);
>> +    acpi_hdr_p->checksum = acpi_checksum((uint8_t*)p, length);
>>      /* increase number of tables */
>>      (*(uint16_t*)acpi_tables) =
>>           cpu_to_le32(le32_to_cpu(*(uint16_t*)acpi_tables) + 1);
>> --
>> 1.7.1.1
>>
>
> --
> yamahata
>
>