* Avoid incrementing by moving comma into strlen("uuid_disk=,") and
considering NUL byte.
* Appending a UUID only adds UUID_STR_LEN bytes.
Don't count the terminating NUL.
* The length of the hexadecimal representation of lba_int is
2 * sizeof(lba_int).
* We don't use a 'MiB' postfix but a '0x' prefix.
* The uuid field is only needed if configured.
Fixes: 2fcaa413b3f6 ("gpt: harden set_gpt_info() against non NULL-terminated
strings")
Signed-off-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
---
v2:
new patch
---
cmd/gpt.c | 33 ++++++++++++++++++++-------------
1 file changed, 20 insertions(+), 13 deletions(-)
diff --git a/cmd/gpt.c b/cmd/gpt.c
index 092f7defff..e7a53747fc 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -162,22 +162,29 @@ static bool found_key(const char *str, const char *key)
return result;
}
+/**
+ * calc_parts_list_len() - get size of partition table description
+ *
+ * @numparts: number of partitions
+ * Return: string size including terminating NUL
+ */
static int calc_parts_list_len(int numparts)
{
- int partlistlen = UUID_STR_LEN + 1 + strlen("uuid_disk=");
- /* for the comma */
- partlistlen++;
-
- /* per-partition additions; numparts starts at 1, so this should be
correct */
- partlistlen += numparts * (strlen("name=,") + PART_NAME_LEN + 1);
+ /* number of hexadecimal digits of the lbaint_t representation */
+ const int lbaint_size = 2 * sizeof(lbaint_t);
+ int partlistlen;
+
+ /* media description including terminating NUL */
+ partlistlen = strlen("uuid_disk=;") + UUID_STR_LEN + 1;
+ /* per-partition descriptions; numparts */
+ partlistlen += numparts * (strlen("name=,") + PART_NAME_LEN);
/* see part.h for definition of struct disk_partition */
- partlistlen += numparts * (strlen("start=MiB,") + sizeof(lbaint_t) + 1);
- partlistlen += numparts * (strlen("size=MiB,") + sizeof(lbaint_t) + 1);
- partlistlen += numparts * (strlen("uuid=;") + UUID_STR_LEN + 1);
- /* for the terminating null */
- partlistlen++;
- debug("Length of partitions_list is %d for %d partitions\n",
partlistlen,
- numparts);
+ partlistlen += numparts * (strlen("start=0x,") + lbaint_size);
+ partlistlen += numparts * (strlen("size=0x,") + lbaint_size);
+ if (IS_ENABLED(CONFIG_PARTITION_UUIDS))
+ partlistlen += numparts * (strlen("uuid=;") + UUID_STR_LEN);
+ debug("Length of partitions_list is %d for %d partitions\n",
+ partlistlen, numparts);
return partlistlen;
}
--
2.40.1
