From: Ye Bin <yebin10@xxxxxxxxxx> [ Upstream commit fdc2a3c75dd8345c5b48718af90bad1a7811bedb ] Introduce EXT4_FC_TAG_BASE_LEN helper for calculate length of struct ext4_fc_tl. Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220924075233.2315259-2-yebin10@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Stable-dep-of: 1b45cc5c7b92 ("ext4: fix potential out of bound read in ext4_fc_replay_scan()") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ext4/fast_commit.c | 54 ++++++++++++++++++++++--------------------- fs/ext4/fast_commit.h | 3 +++ 2 files changed, 31 insertions(+), 26 deletions(-) diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c index b26f304baa52..6c8b78ad0ff2 100644 --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -710,10 +710,10 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc) * After allocating len, we should have space at least for a 0 byte * padding. */ - if (len + sizeof(struct ext4_fc_tl) > bsize) + if (len + EXT4_FC_TAG_BASE_LEN > bsize) return NULL; - if (bsize - off - 1 > len + sizeof(struct ext4_fc_tl)) { + if (bsize - off - 1 > len + EXT4_FC_TAG_BASE_LEN) { /* * Only allocate from current buffer if we have enough space for * this request AND we have space to add a zero byte padding. @@ -730,10 +730,10 @@ static u8 *ext4_fc_reserve_space(struct super_block *sb, int len, u32 *crc) /* Need to add PAD tag */ tl = (struct ext4_fc_tl *)(sbi->s_fc_bh->b_data + off); tl->fc_tag = cpu_to_le16(EXT4_FC_TAG_PAD); - pad_len = bsize - off - 1 - sizeof(struct ext4_fc_tl); + pad_len = bsize - off - 1 - EXT4_FC_TAG_BASE_LEN; tl->fc_len = cpu_to_le16(pad_len); if (crc) - *crc = ext4_chksum(sbi, *crc, tl, sizeof(*tl)); + *crc = ext4_chksum(sbi, *crc, tl, EXT4_FC_TAG_BASE_LEN); if (pad_len > 0) ext4_fc_memzero(sb, tl + 1, pad_len, crc); ext4_fc_submit_bh(sb, false); @@ -775,7 +775,7 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc) * ext4_fc_reserve_space takes care of allocating an extra block if * there's no enough space on this block for accommodating this tail. */ - dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(tail), &crc); + dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + sizeof(tail), &crc); if (!dst) return -ENOSPC; @@ -785,8 +785,8 @@ static int ext4_fc_write_tail(struct super_block *sb, u32 crc) tl.fc_len = cpu_to_le16(bsize - off - 1 + sizeof(struct ext4_fc_tail)); sbi->s_fc_bytes = round_up(sbi->s_fc_bytes, bsize); - ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), &crc); - dst += sizeof(tl); + ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, &crc); + dst += EXT4_FC_TAG_BASE_LEN; tail.fc_tid = cpu_to_le32(sbi->s_journal->j_running_transaction->t_tid); ext4_fc_memcpy(sb, dst, &tail.fc_tid, sizeof(tail.fc_tid), &crc); dst += sizeof(tail.fc_tid); @@ -808,15 +808,15 @@ static bool ext4_fc_add_tlv(struct super_block *sb, u16 tag, u16 len, u8 *val, struct ext4_fc_tl tl; u8 *dst; - dst = ext4_fc_reserve_space(sb, sizeof(tl) + len, crc); + dst = ext4_fc_reserve_space(sb, EXT4_FC_TAG_BASE_LEN + len, crc); if (!dst) return false; tl.fc_tag = cpu_to_le16(tag); tl.fc_len = cpu_to_le16(len); - ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc); - ext4_fc_memcpy(sb, dst + sizeof(tl), val, len, crc); + ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc); + ext4_fc_memcpy(sb, dst + EXT4_FC_TAG_BASE_LEN, val, len, crc); return true; } @@ -828,8 +828,8 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc, struct ext4_fc_dentry_info fcd; struct ext4_fc_tl tl; int dlen = fc_dentry->fcd_name.len; - u8 *dst = ext4_fc_reserve_space(sb, sizeof(tl) + sizeof(fcd) + dlen, - crc); + u8 *dst = ext4_fc_reserve_space(sb, + EXT4_FC_TAG_BASE_LEN + sizeof(fcd) + dlen, crc); if (!dst) return false; @@ -838,8 +838,8 @@ static bool ext4_fc_add_dentry_tlv(struct super_block *sb, u32 *crc, fcd.fc_ino = cpu_to_le32(fc_dentry->fcd_ino); tl.fc_tag = cpu_to_le16(fc_dentry->fcd_op); tl.fc_len = cpu_to_le16(sizeof(fcd) + dlen); - ext4_fc_memcpy(sb, dst, &tl, sizeof(tl), crc); - dst += sizeof(tl); + ext4_fc_memcpy(sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc); + dst += EXT4_FC_TAG_BASE_LEN; ext4_fc_memcpy(sb, dst, &fcd, sizeof(fcd), crc); dst += sizeof(fcd); ext4_fc_memcpy(sb, dst, fc_dentry->fcd_name.name, dlen, crc); @@ -876,13 +876,13 @@ static int ext4_fc_write_inode(struct inode *inode, u32 *crc) ret = -ECANCELED; dst = ext4_fc_reserve_space(inode->i_sb, - sizeof(tl) + inode_len + sizeof(fc_inode.fc_ino), crc); + EXT4_FC_TAG_BASE_LEN + inode_len + sizeof(fc_inode.fc_ino), crc); if (!dst) goto err; - if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, sizeof(tl), crc)) + if (!ext4_fc_memcpy(inode->i_sb, dst, &tl, EXT4_FC_TAG_BASE_LEN, crc)) goto err; - dst += sizeof(tl); + dst += EXT4_FC_TAG_BASE_LEN; if (!ext4_fc_memcpy(inode->i_sb, dst, &fc_inode, sizeof(fc_inode), crc)) goto err; dst += sizeof(fc_inode); @@ -2036,9 +2036,10 @@ static int ext4_fc_replay_scan(journal_t *journal, } state->fc_replay_expected_off++; - for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) { - memcpy(&tl, cur, sizeof(tl)); - val = cur + sizeof(tl); + for (cur = start; cur < end; + cur = cur + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)) { + memcpy(&tl, cur, EXT4_FC_TAG_BASE_LEN); + val = cur + EXT4_FC_TAG_BASE_LEN; ext4_debug("Scan phase, tag:%s, blk %lld\n", tag2str(le16_to_cpu(tl.fc_tag)), bh->b_blocknr); switch (le16_to_cpu(tl.fc_tag)) { @@ -2061,13 +2062,13 @@ static int ext4_fc_replay_scan(journal_t *journal, case EXT4_FC_TAG_PAD: state->fc_cur_tag++; state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur, - sizeof(tl) + le16_to_cpu(tl.fc_len)); + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)); break; case EXT4_FC_TAG_TAIL: state->fc_cur_tag++; memcpy(&tail, val, sizeof(tail)); state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur, - sizeof(tl) + + EXT4_FC_TAG_BASE_LEN + offsetof(struct ext4_fc_tail, fc_crc)); if (le32_to_cpu(tail.fc_tid) == expected_tid && @@ -2094,7 +2095,7 @@ static int ext4_fc_replay_scan(journal_t *journal, } state->fc_cur_tag++; state->fc_crc = ext4_chksum(sbi, state->fc_crc, cur, - sizeof(tl) + le16_to_cpu(tl.fc_len)); + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)); break; default: ret = state->fc_replay_num_tags ? @@ -2149,9 +2150,10 @@ static int ext4_fc_replay(journal_t *journal, struct buffer_head *bh, start = (u8 *)bh->b_data; end = (__u8 *)bh->b_data + journal->j_blocksize - 1; - for (cur = start; cur < end; cur = cur + sizeof(tl) + le16_to_cpu(tl.fc_len)) { - memcpy(&tl, cur, sizeof(tl)); - val = cur + sizeof(tl); + for (cur = start; cur < end; + cur = cur + EXT4_FC_TAG_BASE_LEN + le16_to_cpu(tl.fc_len)) { + memcpy(&tl, cur, EXT4_FC_TAG_BASE_LEN); + val = cur + EXT4_FC_TAG_BASE_LEN; if (state->fc_replay_num_tags == 0) { ret = JBD2_FC_REPLAY_STOP; diff --git a/fs/ext4/fast_commit.h b/fs/ext4/fast_commit.h index 1db12847a83b..a6154c3ed135 100644 --- a/fs/ext4/fast_commit.h +++ b/fs/ext4/fast_commit.h @@ -70,6 +70,9 @@ struct ext4_fc_tail { __le32 fc_crc; }; +/* Tag base length */ +#define EXT4_FC_TAG_BASE_LEN (sizeof(struct ext4_fc_tl)) + /* * Fast commit status codes */ -- 2.35.1
