30.03.2016 17:09, Ignat Korchagin пишет:
> Implemented as a separate function which should process arbitrary length data.
TBH I still think that simply setting READBUF_SIZE to 64K is the
simplest solution.
> As for tests, it seems that the easiest way is to add this signature
to tests/file_filter. Not sure how should I send you the patch with
binary data though.
>
Just sign files and send new signatures and keys, I will commit them.
> diff --git a/grub-core/commands/verify.c b/grub-core/commands/verify.c
> index 166d0aa..cc8fa39 100644
> --- a/grub-core/commands/verify.c
> +++ b/grub-core/commands/verify.c
> @@ -445,6 +445,88 @@ rsa_pad (gcry_mpi_t *hmpi, grub_uint8_t *hval,
> return ret;
> }
>
> +static grub_uint64_t
> +grub_subpacket_keyid_search (grub_file_t f, grub_ssize_t sub_len,
> + const gcry_md_spec_t *hash, void *context)
This does more than just searching for keyid, it also hashes content, so
name is misleading.
> +{
> + grub_uint64_t keyid = 0;
> + grub_uint8_t *readbuf = NULL;
> +
> + while (sub_len > 0)
> + {
> + grub_uint8_t szid[5];
> + grub_size_t sz_len;
> + grub_size_t l;
> +
> + grub_ssize_t r = grub_file_read (f, szid, 1);
> + if (r != 1)
> + return 0;
> +
> + if (szid[0] < 192)
> + {
> + l = szid[0];
> + sz_len = 1;
> + }
> + else if (szid[0] < 255)
> + {
> + r = grub_file_read (f, szid + 1, 1);
> + if (r != 1)
> + return 0;
> +
> + l = (((szid[0] & ~192) << GRUB_CHAR_BIT) | szid[1]) + 192;
> + sz_len = 2;
> + }
> + else
> + {
> + r = grub_file_read (f, szid + 1, 4);
> + if (r != 4)
> + return 0;
> +
> + l = grub_be_to_cpu32 (grub_get_unaligned32 (szid + 1));
> + sz_len = 5;
> + }
> +
> + readbuf = grub_zalloc (l);
So you allocate full subpacket length anyway. Why not set READBUF_SIZE
to max size then from the very start?
> + if (!readbuf)
> + return 0;
> +
> + r = grub_file_read (f, readbuf, l);
> + if (r <= 0)
> + goto fail;
> +
> + while ((grub_size_t)r < l)
> + {
> + grub_ssize_t rr = grub_file_read (f, readbuf + r, l -
> (grub_size_t)r);
> + if (rr <= 0)
> + goto fail;
> + r += rr;
> + }
> +
> + if (*readbuf == 0x10 && l >= 8)
> + keyid = grub_get_unaligned64 (readbuf + 1);
> +
> + if (hash && context)
> + {
> + hash->write (context, szid, sz_len);
> + hash->write (context, readbuf, l);
> + }
> +
> + grub_free (readbuf);
> + readbuf = NULL;
> +
> + sub_len -= sz_len + l;
> + }
> +
> +fail:
> + if (readbuf)
> + {
> + grub_free (readbuf);
> + return 0;
> + }
> +
> + return keyid;
> +}
> +
> static grub_err_t
> grub_verify_signature_real (char *buf, grub_size_t size,
> grub_file_t f, grub_file_t sig,
> @@ -532,17 +614,7 @@ grub_verify_signature_real (char *buf, grub_size_t size,
>
> hash->write (context, &v, sizeof (v));
> hash->write (context, &v4, sizeof (v4));
> - while (rem)
> - {
> - r = grub_file_read (sig, readbuf,
> - rem < READBUF_SIZE ? rem : READBUF_SIZE);
> - if (r < 0)
> - goto fail;
> - if (r == 0)
> - break;
> - hash->write (context, readbuf, r);
> - rem -= r;
> - }
> + keyid = grub_subpacket_keyid_search (sig, rem, hash, context);
> hash->write (context, &v, sizeof (v));
> s = 0xff;
> hash->write (context, &s, sizeof (s));
> @@ -550,37 +622,11 @@ grub_verify_signature_real (char *buf, grub_size_t size,
> r = grub_file_read (sig, &unhashed_sub, sizeof (unhashed_sub));
> if (r != sizeof (unhashed_sub))
> goto fail;
> - {
> - grub_uint8_t *ptr;
> - grub_uint32_t l;
> - rem = grub_be_to_cpu16 (unhashed_sub);
> - if (rem > READBUF_SIZE)
> - goto fail;
> - r = grub_file_read (sig, readbuf, rem);
> - if (r != rem)
> - goto fail;
> - for (ptr = readbuf; ptr < readbuf + rem; ptr += l)
> - {
> - if (*ptr < 192)
> - l = *ptr++;
> - else if (*ptr < 255)
> - {
> - if (ptr + 1 >= readbuf + rem)
> - break;
> - l = (((ptr[0] & ~192) << GRUB_CHAR_BIT) | ptr[1]) + 192;
> - ptr += 2;
> - }
> - else
> - {
> - if (ptr + 5 >= readbuf + rem)
> - break;
> - l = grub_be_to_cpu32 (grub_get_unaligned32 (ptr + 1));
> - ptr += 5;
> - }
> - if (*ptr == 0x10 && l >= 8)
> - keyid = grub_get_unaligned64 (ptr + 1);
> - }
> - }
> + rem = grub_be_to_cpu16 (unhashed_sub);
> + if (keyid == 0)
> + keyid = grub_subpacket_keyid_search (sig, rem, NULL, NULL);
> + else
> + grub_subpacket_keyid_search (sig, rem, NULL, NULL);
>
> hash->final (context);
>
>
>
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>
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