On 7/31/26 14:40, Alexey Charkov wrote:
Several GPT header fields are read without converting from
little-endian, which is wrong on big-endian hosts.
gpt_fill_pte() takes my_lba and partition_entry_lba raw when working out
the region a partition must not overlap, so on a big-endian host both
bounds are byte-swapped garbage and the overlap check does not do
anything useful.
gpt_verify_partitions() compares the loop counter against
num_partition_entries raw, so its "More partitions than allowed!" guard
never triggers.
It also swaps gpt_part_size, which is already in host order, having been
computed from two le64_to_cpu() results a few lines above. Drop the
conversion rather than adding one.
All of this is a no-op on little-endian targets.
Signed-off-by: Alexey Charkov <[email protected]>
This change is not covered by the test in patch 6/6 as it runs only on
the sandbox.
Please, ensure that the GPT tests are also executed on a big-endian
systems, e.g malta64_defconfig which run in the CI via QEMU.
Reviewed-by: Heinrich Schuchardt <[email protected]>
---
disk/part_efi.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/disk/part_efi.c b/disk/part_efi.c
index af311867a285..062389c3af0c 100644
--- a/disk/part_efi.c
+++ b/disk/part_efi.c
@@ -462,10 +462,10 @@ int gpt_fill_pte(struct blk_desc *desc,
char *str_type_guid;
unsigned char *bin_type_guid;
#endif
- size_t hdr_start = gpt_h->my_lba;
+ size_t hdr_start = le64_to_cpu(gpt_h->my_lba);
size_t hdr_end = hdr_start + 1;
- size_t pte_start = gpt_h->partition_entry_lba;
+ size_t pte_start = le64_to_cpu(gpt_h->partition_entry_lba);
size_t pte_end = pte_start + gpt_pte_blocks(desc, gpt_h);
for (i = 0; i < parts; i++) {
@@ -851,7 +851,7 @@ int gpt_verify_partitions(struct blk_desc *desc,
gpt_e = *gpt_pte;
for (i = 0; i < parts; i++) {
- if (i == gpt_head->num_partition_entries) {
+ if (i == le32_to_cpu(gpt_head->num_partition_entries)) {
pr_err("More partitions than allowed!\n");
return -1;
}
@@ -877,7 +877,7 @@ int gpt_verify_partitions(struct blk_desc *desc,
(unsigned long long)gpt_part_size,
(unsigned long long)partitions[i].size);
- if (le64_to_cpu(gpt_part_size) != partitions[i].size) {
+ if (gpt_part_size != partitions[i].size) {
/* We do not check the extend partition size */
if ((i == parts - 1) && (partitions[i].size == 0))
continue;
