[PATCH] f2fs: compress: do sanity check on cluster

Chao Yu
2021-08-03T10:40:11Z

This patch adds f2fs_sanity_check_cluster() to support doing
sanity check on cluster of compressed file, it will be triggered
from below two paths:

- __f2fs_cluster_blocks()
- f2fs_map_blocks(F2FS_GET_BLOCK_FIEMAP)

And it can detect below three kind of cluster insanity status.

C: COMPRESS_ADDR
N: NULL_ADDR or NEW_ADDR
V: valid blkaddr
*: any value

1. [*|C|*|*]
2. [C|*|C|*]
3. [C|N|N|V]

Signed-off-by: Chao Yu <chao@kernel.org>
---
fs/f2fs/compress.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++
fs/f2fs/data.c | 21 ++++++++++++------
fs/f2fs/f2fs.h | 1 +
3 files changed, 68 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 455561826c7d..4aa166d3d9bf 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -898,6 +898,54 @@ static bool cluster_has_invalid_data(struct compress_ctx *cc)
return false;
}

+bool f2fs_sanity_check_cluster(struct dnode_of_data *dn)
+{
+ struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
+ unsigned int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
+ bool compressed = dn->data_blkaddr == COMPRESS_ADDR;
+ int cluster_end = 0;
+ int i;
+ char *reason = "";
+
+ if (!compressed)
+ return false;
+
+ /* [..., COMPR_ADDR, ...] */
+ if (dn->ofs_in_node % cluster_size) {
+ reason = "[*|C|*|*]";
+ goto out;
+ }
+
+ for (i = 1; i < cluster_size; i++) {
+ block_t blkaddr = data_blkaddr(dn->inode, dn->node_page,
+ dn->ofs_in_node + i);
+
+ /* [COMPR_ADDR, ..., COMPR_ADDR] */
+ if (blkaddr == COMPRESS_ADDR) {
+ reason = "[C|*|C|*]";
+ goto out;
+ }
+ if (compressed) {
+ if (!__is_valid_data_blkaddr(blkaddr)) {
+ if (!cluster_end)
+ cluster_end = i;
+ continue;
+ }
+ /* [COMPR_ADDR, NULL_ADDR or NEW_ADDR, valid_blkaddr] */
+ if (cluster_end) {
+ reason = "[C|N|N|V]";
+ goto out;
+ }
+ }
+ }
+ return false;
+out:
+ f2fs_warn(sbi, "access invalid cluster, ino:%lu, nid:%u, ofs_in_node:%u, reason:%s",
+ dn->inode->i_ino, dn->nid, dn->ofs_in_node, reason);
+ set_sbi_flag(sbi, SBI_NEED_FSCK);
+ return true;
+}
+
static int __f2fs_cluster_blocks(struct inode *inode,
unsigned int cluster_idx, bool compr)
{
@@ -915,6 +963,11 @@ static int __f2fs_cluster_blocks(struct inode *inode,
goto fail;
}

+ if (f2fs_sanity_check_cluster(&dn)) {
+ ret = -EFSCORRUPTED;
+ goto fail;
+ }
+
if (dn.data_blkaddr == COMPRESS_ADDR) {
int i;

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 948083c88d17..75dda2035f68 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1558,13 +1558,20 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
}
if (flag == F2FS_GET_BLOCK_PRECACHE)
goto sync_out;
- if (flag == F2FS_GET_BLOCK_FIEMAP &&
- blkaddr == NULL_ADDR) {
- if (map->m_next_pgofs)
- *map->m_next_pgofs = pgofs + 1;
- goto sync_out;
- }
- if (flag != F2FS_GET_BLOCK_FIEMAP) {
+ if (flag == F2FS_GET_BLOCK_FIEMAP) {
+ if (blkaddr == NULL_ADDR) {
+ if (map->m_next_pgofs)
+ *map->m_next_pgofs = pgofs + 1;
+ goto sync_out;
+ }
+#ifdef CONFIG_F2FS_FS_COMPRESSION
+ if (f2fs_compressed_file(inode) &&
+ f2fs_sanity_check_cluster(&dn)) {
+ err = -EFSCORRUPTED;
+ goto sync_out;
+ }
+#endif
+ } else {
/* for defragment case */
if (map->m_next_pgofs)
*map->m_next_pgofs = pgofs + 1;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 20389b9b3eac..86d416ffad61 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -4060,6 +4060,7 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
block_t blkaddr);
bool f2fs_cluster_is_empty(struct compress_ctx *cc);
bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
+bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
int f2fs_write_multi_pages(struct compress_ctx *cc,
int *submitted,
--
2.22.1