From: Eric Biggers <ebiggers@xxxxxxxxxx>
Validate the inode and filename lengths in fast-commit journal records
so that a malicious fast-commit journal cannot cause a crash by having
invalid values for these. Also validate EXT4_FC_TAG_DEL_RANGE.
Fixes: aa75f4d3daae ("ext4: main fast-commit commit path")
Cc: <stable@xxxxxxxxxxxxxxx> # v5.10+
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
fs/ext4/fast_commit.c | 38 +++++++++++++++++++-------------------
fs/ext4/fast_commit.h | 2 +-
2 files changed, 20 insertions(+), 20 deletions(-)
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index 1e8be05542396..d5ad4b2b235d6 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1991,32 +1991,31 @@ void ext4_fc_replay_cleanup(struct super_block *sb)
kfree(sbi->s_fc_replay_state.fc_modified_inodes);
}
-static inline bool ext4_fc_tag_len_isvalid(struct ext4_fc_tl *tl,
- u8 *val, u8 *end)
+static bool ext4_fc_value_len_isvalid(struct ext4_sb_info *sbi,
+ int tag, int len)
{
- if (val + tl->fc_len > end)
- return false;
-
- /* Here only check ADD_RANGE/TAIL/HEAD which will read data when do
- * journal rescan before do CRC check. Other tags length check will
- * rely on CRC check.
- */
- switch (tl->fc_tag) {
+ switch (tag) {
case EXT4_FC_TAG_ADD_RANGE:
- return (sizeof(struct ext4_fc_add_range) == tl->fc_len);
- case EXT4_FC_TAG_TAIL:
- return (sizeof(struct ext4_fc_tail) <= tl->fc_len);
- case EXT4_FC_TAG_HEAD:
- return (sizeof(struct ext4_fc_head) == tl->fc_len);
+ return len == sizeof(struct ext4_fc_add_range);
case EXT4_FC_TAG_DEL_RANGE:
+ return len == sizeof(struct ext4_fc_del_range);
+ case EXT4_FC_TAG_CREAT:
case EXT4_FC_TAG_LINK:
case EXT4_FC_TAG_UNLINK:
- case EXT4_FC_TAG_CREAT:
+ len -= sizeof(struct ext4_fc_dentry_info);
+ return len >= 1 && len <= EXT4_NAME_LEN;
case EXT4_FC_TAG_INODE:
+ len -= sizeof(struct ext4_fc_inode);
+ return len >= EXT4_GOOD_OLD_INODE_SIZE &&
+ len <= sbi->s_inode_size;
case EXT4_FC_TAG_PAD:
- default:
- return true;
+ return true; /* padding can have any length */
+ case EXT4_FC_TAG_TAIL:
+ return len >= sizeof(struct ext4_fc_tail);
+ case EXT4_FC_TAG_HEAD:
+ return len == sizeof(struct ext4_fc_head);
}
+ return false;
}
/*
@@ -2079,7 +2078,8 @@ static int ext4_fc_replay_scan(journal_t *journal,
cur = cur + EXT4_FC_TAG_BASE_LEN + tl.fc_len) {
ext4_fc_get_tl(&tl, cur);
val = cur + EXT4_FC_TAG_BASE_LEN;
- if (!ext4_fc_tag_len_isvalid(&tl, val, end)) {
+ if (tl.fc_len > end - val ||
+ !ext4_fc_value_len_isvalid(sbi, tl.fc_tag, tl.fc_len)) {
ret = state->fc_replay_num_tags ?
JBD2_FC_REPLAY_STOP : -ECANCELED;
goto out_err;
diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h
index 256f2ad27204a..2fadb2c4780c8 100644
--- a/fs/ext4/fast_commit.h
+++ b/fs/ext4/fast_commit.h
@@ -58,7 +58,7 @@ struct ext4_fc_dentry_info {
__u8 fc_dname[];
};
-/* Value structure for EXT4_FC_TAG_INODE and EXT4_FC_TAG_INODE_PARTIAL. */
+/* Value structure for EXT4_FC_TAG_INODE. */
struct ext4_fc_inode {
__le32 fc_ino;
__u8 fc_raw_inode[];
--
2.38.1
