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efidisk: Respect block_io_protocol buffer alignment

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Returned from the OpenProtocol operation, the grub_efi_block_io_media
structure contains the io_align field, specifying the minimum alignment
required for buffers used in any data transfers with the device.

Make grub_efidisk_readwrite() allocate a temporary buffer, aligned to
this boundary, if the buffer passed to it does not already meet the
requirements.

Also sanity check the io_align field in grub_efidisk_open() for
power-of-two-ness and bail if invalid.
This commit is contained in:
Leif Lindholm 2016-02-27 13:44:59 +01:00 committed by Vladimir Serbinenko
parent ca028db3d4
commit 51f375d688
1 changed files with 41 additions and 7 deletions
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48
grub-core/disk/efi/efidisk.c
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@ -493,8 +493,15 @@ grub_efidisk_open (const char *name, struct grub_disk *disk)
m = d->block_io->media;
/* FIXME: Probably it is better to store the block size in the disk,
and total sectors should be replaced with total blocks. */
grub_dprintf ("efidisk", "m = %p, last block = %llx, block size = %x\n",
m, (unsigned long long) m->last_block, m->block_size);
grub_dprintf ("efidisk",
"m = %p, last block = %llx, block size = %x, io align = %x\n",
m, (unsigned long long) m->last_block, m->block_size,
m->io_align);
/* Ensure required buffer alignment is a power of two (or is zero). */
if (m->io_align & (m->io_align - 1))
return grub_error (GRUB_ERR_IO, "invalid buffer alignment %d", m->io_align);
disk->total_sectors = m->last_block + 1;
/* Don't increase this value due to bug in some EFI. */
disk->max_agglomerate = 0xa0000 >> (GRUB_DISK_CACHE_BITS + GRUB_DISK_SECTOR_BITS);
@ -524,15 +531,42 @@ grub_efidisk_readwrite (struct grub_disk *disk, grub_disk_addr_t sector,
{
struct grub_efidisk_data *d;
grub_efi_block_io_t *bio;
grub_efi_status_t status;
grub_size_t io_align, num_bytes;
char *aligned_buf;
d = disk->data;
bio = d->block_io;
return efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
bio->media->media_id,
(grub_efi_uint64_t) sector,
(grub_efi_uintn_t) size << disk->log_sector_size,
buf);
/* Set alignment to 1 if 0 specified */
io_align = bio->media->io_align ? bio->media->io_align : 1;
num_bytes = size << disk->log_sector_size;
if ((grub_addr_t) buf & (io_align - 1))
{
aligned_buf = grub_memalign (io_align, num_bytes);
if (! aligned_buf)
return GRUB_EFI_OUT_OF_RESOURCES;
if (wr)
grub_memcpy (aligned_buf, buf, num_bytes);
}
else
{
aligned_buf = buf;
}
status = efi_call_5 ((wr ? bio->write_blocks : bio->read_blocks), bio,
bio->media->media_id, (grub_efi_uint64_t) sector,
(grub_efi_uintn_t) num_bytes, aligned_buf);
if ((grub_addr_t) buf & (io_align - 1))
{
if (!wr)
grub_memcpy (buf, aligned_buf, num_bytes);
grub_free (aligned_buf);
}
return status;
}
static grub_err_t