diff options
| -rw-r--r-- | boot.c | 19 |
1 files changed, 19 insertions, 0 deletions
@@ -106,6 +106,25 @@ readboot(dosfs, boot) boot->FSInfo = block[48] + (block[49] << 8); boot->Backup = block[50] + (block[51] << 8); + /* If the OEM Name field is EXFAT, it's not FAT32, so bail */ + if (!memcmp(&block[3], "EXFAT ", 8)) { + pfatal("exFAT filesystem is not supported."); + return FSFATAL; + } + + /* check basic parameters */ + if ((boot->FSInfo == 0) || + (boot->BytesPerSec % DOSBOOTBLOCKSIZE != 0) || + (boot->BytesPerSec / DOSBOOTBLOCKSIZE == 0) || + (boot->SecPerClust == 0)) { + /* + * Either the BIOS Parameter Block has been corrupted, + * or this is not a FAT32 filesystem, most likely an + * exFAT filesystem. + */ + pfatal("Invalid FAT32 Extended BIOS Parameter Block"); + return FSFATAL; + } if (lseek(dosfs, boot->FSInfo * boot->BytesPerSec, SEEK_SET) != boot->FSInfo * boot->BytesPerSec || read(dosfs, fsinfo, sizeof fsinfo) |