Skip to content

badblocks: fix infinite loop due to incorrect rounding and overflow #774

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
blktests-ci wants to merge 1 commit into
base: linus-master_base
Choose a base branch
from
+34 −9
Open

badblocks: fix infinite loop due to incorrect rounding and overflow #774

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
43 changes: 34 additions & 9 deletions block/badblocks.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -855,13 +855,21 @@ static bool _badblocks_set(struct badblocks *bb, sector_t s, sector_t sectors,

if (bb->shift) {
/* round the start down, and the end up */
if (s > ULLONG_MAX - sectors)
return false;
sector_t next = s + sectors;

rounddown(s, 1 << bb->shift);
roundup(next, 1 << bb->shift);
sectors = next - s;
s = rounddown(s, 1 << bb->shift);
next = roundup(next, 1 << bb->shift);
if (next < s)
sectors = 0;
else
sectors = next - s;
}

if (sectors == 0)
return false;

write_seqlock_irqsave(&bb->lock, flags);

bad.ack = acknowledged;
Expand Down Expand Up @@ -1070,12 +1078,20 @@ static bool _badblocks_clear(struct badblocks *bb, sector_t s, sector_t sectors)
* However it is better the think a block is bad when it
* isn't than to think a block is not bad when it is.
*/
if (s > ULLONG_MAX - sectors)
return false;
target = s + sectors;
roundup(s, 1 << bb->shift);
rounddown(target, 1 << bb->shift);
sectors = target - s;
s = roundup(s, 1 << bb->shift);
target = rounddown(target, 1 << bb->shift);
if (target < s)
sectors = 0;
else
sectors = target - s;
}

if (sectors == 0)
return false;

write_seqlock_irq(&bb->lock);

bad.ack = true;
Expand Down Expand Up @@ -1305,11 +1321,20 @@ int badblocks_check(struct badblocks *bb, sector_t s, sector_t sectors,

if (bb->shift > 0) {
/* round the start down, and the end up */
if (s > ULLONG_MAX - sectors) {
return -EINVAL;
}
sector_t target = s + sectors;

rounddown(s, 1 << bb->shift);
roundup(target, 1 << bb->shift);
sectors = target - s;
s = rounddown(s, 1 << bb->shift);
target = roundup(target, 1 << bb->shift);
if (target < s)
sectors = 0;
else
sectors = target - s;

if (sectors == 0)
return 0;
}

retry:
Expand Down