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fat: Make signature checking even more lax

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This commit is contained in:
mintsuki 2022-07-10 19:50:19 +02:00
parent 77616a0218
commit e7e73ae6fe
1 changed files with 6 additions and 14 deletions
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20
common/fs/fat32.s2.c
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@ -104,27 +104,19 @@ static int fat32_init_context(struct fat32_context* context, struct volume *part
struct fat32_bpb bpb;
volume_read(context->part, &bpb, 0, sizeof(struct fat32_bpb));
// Generic check
if (*(uint16_t *)(((void *)&bpb) + 510) != 0xaa55) {
return 1;
}
// Checks for FAT12/16
if (strncmp((((void *)&bpb) + 0x36), "FAT", 3) == 0) {
uint8_t sig = *(((uint8_t *)&bpb) + 0x26);
if (sig == 0x29 || sig == 0xd0) {
goto valid;
}
goto valid;
}
// Checks for FAT32
if (strncmp((((void *)&bpb) + 0x52), "FAT", 3) == 0) {
uint8_t sig = *(((uint8_t *)&bpb) + 0x42);
goto valid;
}
if (sig == 0x29 || sig == 0x28 || sig == 0xd0) {
goto valid;
}
// Checks for FAT32 (with 64-bit sector count)
if (strncmp((((void *)&bpb) + 0x03), "FAT32", 5) == 0) {
goto valid;
}
return 1;