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SubjectRE: [PATCH 3/4] exfat: add boot region verification
Date
[snip]
> +static int exfat_verify_boot_region(struct super_block *sb) {
> + struct buffer_head *bh = NULL;
> + u32 chksum = 0, *p_sig, *p_chksum;
> + int sn, i;
> +
> + /* read boot sector sub-regions */
> + for (sn = 0; sn < 11; sn++) {
> + bh = sb_bread(sb, sn);
> + if (!bh)
> + return -EIO;
> +
> + if (sn != 0 && sn <= 8) {
> + /* extended boot sector sub-regions */
> + p_sig = (u32 *)&bh->b_data[sb->s_blocksize - 4];
> + if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE) {
> + exfat_err(sb, "no exboot-signature");
exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x", sn, *p_sig);
> + brelse(bh);
> + return -EINVAL;
Don't make mount error, Just print warning message.
> + }
> + }
> +
> + chksum = exfat_calc_chksum32(bh->b_data, sb->s_blocksize,
> + chksum, sn ? CS_DEFAULT : CS_BOOT_SECTOR);
> + brelse(bh);
> + }
> +
> + /* boot checksum sub-regions */
> + bh = sb_bread(sb, sn);
> + if (!bh)
> + return -EIO;
> +
> + for (i = 0; i < sb->s_blocksize; i += sizeof(u32)) {
> + p_chksum = (u32 *)&bh->b_data[i];
> + if (le32_to_cpu(*p_chksum) != chksum) {
> + exfat_err(sb, "mismatch checksum");
Print invalid checksum value also.
> + brelse(bh);
> + return -EINVAL;
> + }
> + }
> + brelse(bh);
> + return 0;
> +}
> +
> /* mount the file system volume */
> static int __exfat_fill_super(struct super_block *sb) { @@ -498,6 +542,12 @@ static int
> __exfat_fill_super(struct super_block *sb)
> goto free_bh;
> }
>
> + ret = exfat_verify_boot_region(sb);
> + if (ret) {
> + exfat_err(sb, "invalid boot region");
> + goto free_bh;
> + }
> +
> ret = exfat_create_upcase_table(sb);
> if (ret) {
> exfat_err(sb, "failed to load upcase table");
> --
> 2.25.1


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