qemu/qcow2-bitmap-Fix-uint64_t-left-shift-ove.patch
2019-11-07 20:37:13 +00:00

67 lines
2.6 KiB
Diff

From: Tuguoyi <tu.guoyi@h3c.com>
Date: Fri, 1 Nov 2019 07:37:35 +0000
Subject: qcow2-bitmap: Fix uint64_t left-shift overflow
Git-commit: 570542ecb11e04b61ef4b3f4d0965a6915232a88
There are two issues in In check_constraints_on_bitmap(),
1) The sanity check on the granularity will cause uint64_t
integer left-shift overflow when cluster_size is 2M and the
granularity is BIGGER than 32K.
2) The way to calculate image size that the maximum bitmap
supported can map to is a bit incorrect.
This patch fix it by add a helper function to calculate the
number of bytes needed by a normal bitmap in image and compare
it to the maximum bitmap bytes supported by qemu.
Fixes: 5f72826e7fc62167cf3a
Signed-off-by: Guoyi Tu <tu.guoyi@h3c.com>
Message-id: 4ba40cd1e7ee4a708b40899952e49f22@h3c.com
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Bruce Rogers <brogers@suse.com>
---
block/qcow2-bitmap.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c
index b2487101edec0bdde613c561da89..65034da1c0766603d273c200797d 100644
--- a/block/qcow2-bitmap.c
+++ b/block/qcow2-bitmap.c
@@ -142,6 +142,13 @@ static int check_table_entry(uint64_t entry, int cluster_size)
return 0;
}
+static int64_t get_bitmap_bytes_needed(int64_t len, uint32_t granularity)
+{
+ int64_t num_bits = DIV_ROUND_UP(len, granularity);
+
+ return DIV_ROUND_UP(num_bits, 8);
+}
+
static int check_constraints_on_bitmap(BlockDriverState *bs,
const char *name,
uint32_t granularity,
@@ -150,6 +157,7 @@ static int check_constraints_on_bitmap(BlockDriverState *bs,
BDRVQcow2State *s = bs->opaque;
int granularity_bits = ctz32(granularity);
int64_t len = bdrv_getlength(bs);
+ int64_t bitmap_bytes;
assert(granularity > 0);
assert((granularity & (granularity - 1)) == 0);
@@ -171,9 +179,9 @@ static int check_constraints_on_bitmap(BlockDriverState *bs,
return -EINVAL;
}
- if ((len > (uint64_t)BME_MAX_PHYS_SIZE << granularity_bits) ||
- (len > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size <<
- granularity_bits))
+ bitmap_bytes = get_bitmap_bytes_needed(len, granularity);
+ if ((bitmap_bytes > (uint64_t)BME_MAX_PHYS_SIZE) ||
+ (bitmap_bytes > (uint64_t)BME_MAX_TABLE_SIZE * s->cluster_size))
{
error_setg(errp, "Too much space will be occupied by the bitmap. "
"Use larger granularity");