proxmox-mirrors/grub2
1
0
Fork 0
mirror of https://git.proxmox.com/git/grub2 synced 2025-07-24 19:01:43 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

zfs: Fix possible negative shift operation

Browse Source 
While it is possible for the return value from zfs_log2() to be zero
(0), it is quite unlikely, given that the previous assignment to blksz
is shifted up by SPA_MINBLOCKSHIFT (9) before 9 is subtracted at the
assignment to epbs.

But, while unlikely during a normal operation, it may be that a carefully
crafted ZFS filesystem could result in a zero (0) value to the
dn_datalbkszsec field, which means that the shift left does nothing
and assigns zero (0) to blksz, resulting in a negative epbs value.

Fixes: CID 73608

Signed-off-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Darren Kenny 2020-11-24 16:41:49 +00:00 committed by Daniel Kiper
parent 2298f6e0d9
commit a02091834d
1 changed files with 5 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
grub-core/fs/zfs/zfs.c
View File

@ -2670,6 +2670,11 @@ dnode_get (dnode_end_t * mdn, grub_uint64_t objnum, grub_uint8_t type,
blksz = grub_zfs_to_cpu16 (mdn->dn.dn_datablkszsec,
mdn->endian) << SPA_MINBLOCKSHIFT;
epbs = zfs_log2 (blksz) - DNODE_SHIFT;
/* While this should never happen, we should check that epbs is not negative. */
if (epbs < 0)
epbs = 0;
blkid = objnum >> epbs;
idx = objnum & ((1 << epbs) - 1);