diff options
Diffstat (limited to 'fs/exfat/super.c')
| -rw-r--r-- | fs/exfat/super.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/fs/exfat/super.c b/fs/exfat/super.c index 6a1330be5a9a..405717e4e3ea 100644 --- a/fs/exfat/super.c +++ b/fs/exfat/super.c @@ -491,6 +491,50 @@ static int exfat_read_boot_sector(struct super_block *sb) return 0; } +static int exfat_verify_boot_region(struct super_block *sb) +{ + struct buffer_head *bh = NULL; + u32 chksum = 0; + __le32 *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 = (__le32 *)&bh->b_data[sb->s_blocksize - 4]; + if (le32_to_cpu(*p_sig) != EXBOOT_SIGNATURE) + exfat_warn(sb, "Invalid exboot-signature(sector = %d): 0x%08x", + sn, le32_to_cpu(*p_sig)); + } + + 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 = (__le32 *)&bh->b_data[i]; + if (le32_to_cpu(*p_chksum) != chksum) { + exfat_err(sb, "Invalid boot checksum (boot checksum : 0x%08x, checksum : 0x%08x)", + le32_to_cpu(*p_chksum), chksum); + brelse(bh); + return -EINVAL; + } + } + brelse(bh); + return 0; +} + /* mount the file system volume */ static int __exfat_fill_super(struct super_block *sb) { @@ -503,6 +547,12 @@ 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"); |