sblock was local and so considered new variable on every loop
iteration.
While on it, dynamically allocate buffer to reduce stack usage.
Closes: 50597
---
grub-core/fs/btrfs.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/grub-core/fs/btrfs.c b/grub-core/fs/btrfs.c
index 9cffa91..99e81f9 100644
--- a/grub-core/fs/btrfs.c
+++ b/grub-core/fs/btrfs.c
@@ -229,24 +229,29 @@ read_sblock (grub_disk_t disk, struct
grub_btrfs_superblock *sb)
{
unsigned i;
grub_err_t err = GRUB_ERR_NONE;
+ struct grub_btrfs_superblock *sblock;
+
+ sblock = grub_malloc (sizeof (*sblock));
+ if (sblock == NULL)
+ return grub_errno;
+
for (i = 0; i < ARRAY_SIZE (superblock_sectors); i++)
{
- struct grub_btrfs_superblock sblock;
/* Don't try additional superblocks beyond device size. */
- if (i && (grub_le_to_cpu64 (sblock.this_device.size)
+ if (i && (grub_le_to_cpu64 (sblock->this_device.size)
>> GRUB_DISK_SECTOR_BITS) <= superblock_sectors[i])
break;
err = grub_disk_read (disk, superblock_sectors[i], 0,
- sizeof (sblock), &sblock);
+ sizeof (*sblock), sblock);
if (err == GRUB_ERR_OUT_OF_RANGE)
break;
- if (grub_memcmp ((char *) sblock.signature, GRUB_BTRFS_SIGNATURE,
+ if (grub_memcmp ((char *) sblock->signature, GRUB_BTRFS_SIGNATURE,
sizeof (GRUB_BTRFS_SIGNATURE) - 1) != 0)
break;
- if (i == 0 || grub_le_to_cpu64 (sblock.generation)
+ if (i == 0 || grub_le_to_cpu64 (sblock->generation)
> grub_le_to_cpu64 (sb->generation))
- grub_memcpy (sb, &sblock, sizeof (sblock));
+ grub_memcpy (sb, sblock, sizeof (*sblock));
}
if ((err == GRUB_ERR_OUT_OF_RANGE || !err) && i == 0)
@@ -255,6 +260,7 @@ read_sblock (grub_disk_t disk, struct grub_btrfs_superblock
*sb)
if (err == GRUB_ERR_OUT_OF_RANGE)
grub_errno = err = GRUB_ERR_NONE;
+ grub_free (sblock);
return err;
}
--
tg: (8014b7b..) bug/50597 (depends on: master)
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