From: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
Subject: [PATCH v2 09/15] hfsplus: implement get and verify block list header functionality
This patch implements functionality of reading of block list's
header from journal log and veryfing of it.
Signed-off-by: Vyacheslav Dubeyko <slava@xxxxxxxxxxx>
CC: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
CC: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Tested-by: Hin-Tak Leung <htl10@xxxxxxxxxxxxxxxxxxxxx>
---
fs/hfsplus/journal.c | 102 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 102 insertions(+)
diff --git a/fs/hfsplus/journal.c b/fs/hfsplus/journal.c
index b81dc33..d155114 100644
--- a/fs/hfsplus/journal.c
+++ b/fs/hfsplus/journal.c
@@ -49,6 +49,18 @@
#define JHDR_SIZE(jh) \
(le32_to_cpu(((struct hfsplus_journal_header *)(jh))->jhdr_size))
+#define TR_MAX_BLOCKS(blhdr) \
+ (le16_to_cpu(((struct hfsplus_blhdr *)(blhdr))->max_blocks))
+#define TR_BLOCKS(blhdr) \
+ (le16_to_cpu(((struct hfsplus_blhdr *)(blhdr))->num_blocks))
+#define TR_BYTES(blhdr) \
+ (le32_to_cpu(((struct hfsplus_blhdr *)(blhdr))->bytes_used))
+#define TR_SEQ_NUM(blhdr) \
+ (le32_to_cpu(((struct hfsplus_blhdr *)(blhdr))->binfo[0].block.seq_num))
+#define NEED_CHECK_CSUM(blhdr) \
+ (le32_to_cpu(((struct hfsplus_blhdr *)(blhdr))->flags) & \
+ HFSPLUS_BLHDR_CHECK_CHECKSUMS)
+
/*
* struct hfsplus_blist_desc - descriptor of block list buffer
* @start_sec: start sector of block list
@@ -295,12 +307,102 @@ static void hfsplus_deinit_block_list_desc(struct hfsplus_blist_desc *desc)
kfree(desc->dst_buf);
}
+static struct hfsplus_blhdr *hfsplus_get_blhdr(struct super_block *sb,
+ sector_t start_sector,
+ struct hfsplus_blist_desc *desc)
+{
+ struct hfsplus_blhdr *blhdr;
+ int err;
+
+ hfs_dbg(JREPLAY, "get block list header: start_sector %lu\n",
+ start_sector);
+
+ BUG_ON(!desc->blist_buf);
+
+ if (desc->start_sec == start_sector && desc->cur_sec == start_sector)
+ return &desc->blhdr;
+
+ err = hfsplus_submit_bio(sb, start_sector,
+ desc->blist_buf, (void **)&blhdr, READA,
+ &desc->available_bytes);
+ if (err) {
+ pr_err("unable to read block list header\n");
+ return NULL;
+ }
+
+ desc->start_sec = start_sector;
+ desc->cur_sec = start_sector;
+ memcpy((void *)&desc->blhdr, (const void *)blhdr, sizeof(*blhdr));
+ desc->binfo = &blhdr->binfo[0];
+
+ return &desc->blhdr;
+}
+
static inline
bool hfsplus_journal_empty(struct hfsplus_journal_header *jh)
{
return TR_START(jh) == LAST_TR_END(jh);
}
+static inline
+bool hfsplus_transaction_seq_num_valid(u32 prev_seq_num,
+ struct hfsplus_blhdr *blhdr)
+{
+ if (prev_seq_num != 0) {
+ u32 seq = TR_SEQ_NUM(blhdr);
+
+ if ((seq != 0) && (seq != prev_seq_num) &&
+ (seq != (prev_seq_num + 1))) {
+ pr_err("transaction seq number %u is invalid\n",
+ TR_SEQ_NUM(blhdr));
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static
+int hfsplus_verify_blhdr(u32 prev_seq_num, struct hfsplus_blhdr *blhdr)
+{
+ __le32 blhdr_checksum, cksum;
+
+ if (!hfsplus_transaction_seq_num_valid(prev_seq_num, blhdr))
+ return -EIO;
+
+ if (TR_BLOCKS(blhdr) == 0 || TR_BYTES(blhdr) == 0) {
+ pr_err("corrupted block list header\n");
+ hfs_dbg(JOURNAL, "num_blocks %u, max_blocks %u\n",
+ TR_BLOCKS(blhdr), TR_BYTES(blhdr));
+ return -EIO;
+ }
+
+ if (TR_BLOCKS(blhdr) > TR_MAX_BLOCKS(blhdr)) {
+ pr_err("corrupted block list header\n");
+ hfs_dbg(JOURNAL, "num_blocks %u, max_blocks %u\n",
+ TR_BLOCKS(blhdr), TR_MAX_BLOCKS(blhdr));
+ return -EIO;
+ }
+
+ if (!NEED_CHECK_CSUM(blhdr))
+ return 0; /* don't check checksums */
+
+ blhdr_checksum = blhdr->checksum;
+ blhdr->checksum = 0;
+
+ cksum = HFSPLUS_CALC_CHECKSUM((unsigned char *)blhdr, sizeof(*blhdr));
+ if (le32_to_cpu(cksum) != le32_to_cpu(blhdr_checksum)) {
+ blhdr->checksum = blhdr_checksum;
+ pr_err("corrupted block list header\n");
+ hfs_dbg(JOURNAL, "calculated CRC %#x, blhdr_checksum %#x\n",
+ cksum, be32_to_cpu(blhdr_checksum));
+ return -EIO;
+ }
+
+ blhdr->checksum = blhdr_checksum;
+ return 0;
+}
+
static int hfsplus_replay_journal(struct super_block *sb);
static
--
1.7.9.5
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