The definition of bpb's num_total_sectors_16 and num_total_sectors_32 is that either the 16-bit field is non-zero and is used (in which case eg mkfs.fat sets the 32-bit field to zero), or it is zero and the 32-bit field is used. Therefore, a BPB is invalid only if *both* fields are zero; having one field as zero and the other as non-zero is the case to be expected.
This affects all users of grub_chainloader_patch_bpb which are in chainloader.c, freedos.c, and ntldr.c Tested with lDebug booted in qemu via grub2's FreeDOS direct loading support, refer to https://bitbucket.org/ecm/ldosboot + https://bitbucket.org/ecm/ldebug --- grub-core/loader/i386/pc/chainloader.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/grub-core/loader/i386/pc/chainloader.c b/grub-core/loader/i386/pc/chainloader.c index c79c4fe0f..18220b7aa 100644 --- a/grub-core/loader/i386/pc/chainloader.c +++ b/grub-core/loader/i386/pc/chainloader.c @@ -117,7 +117,7 @@ grub_chainloader_patch_bpb (void *bs, grub_device_t dev, grub_uint8_t dl) if (bpb->num_reserved_sectors == 0) break; - if (bpb->num_total_sectors_16 == 0 || bpb->num_total_sectors_32 == 0) + if (bpb->num_total_sectors_16 == 0 && bpb->num_total_sectors_32 == 0) break; if (bpb->num_fats == 0) -- 2.11.0 _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org https://lists.gnu.org/mailman/listinfo/grub-devel
