releases/5.10.99/ext4-fix-error-handling-in-ext4_fc_record_modified_inode.patch

From cdce59a1549190b66f8e3fe465c2b2f714b98a94 Mon Sep 17 00:00:00 2001
From: Ritesh Harjani <riteshh@linux.ibm.com>
Date: Mon, 17 Jan 2022 17:41:49 +0530
Subject: ext4: fix error handling in ext4_fc_record_modified_inode()

From: Ritesh Harjani <riteshh@linux.ibm.com>

commit cdce59a1549190b66f8e3fe465c2b2f714b98a94 upstream.

Current code does not fully takes care of krealloc() error case, which
could lead to silent memory corruption or a kernel bug.  This patch
fixes that.

Also it cleans up some duplicated error handling logic from various
functions in fast_commit.c file.

Reported-by: luo penghao <luo.penghao@zte.com.cn>
Suggested-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/62e8b6a1cce9359682051deb736a3c0953c9d1e9.1642416995.git.riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/ext4/fast_commit.c |   64 ++++++++++++++++++++++----------------------------
 1 file changed, 29 insertions(+), 35 deletions(-)

--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1388,14 +1388,15 @@ static int ext4_fc_record_modified_inode
 		if (state->fc_modified_inodes[i] == ino)
 			return 0;
 	if (state->fc_modified_inodes_used == state->fc_modified_inodes_size) {
-		state->fc_modified_inodes_size +=
-			EXT4_FC_REPLAY_REALLOC_INCREMENT;
 		state->fc_modified_inodes = krealloc(
-					state->fc_modified_inodes, sizeof(int) *
-					state->fc_modified_inodes_size,
-					GFP_KERNEL);
+				state->fc_modified_inodes,
+				sizeof(int) * (state->fc_modified_inodes_size +
+				EXT4_FC_REPLAY_REALLOC_INCREMENT),
+				GFP_KERNEL);
 		if (!state->fc_modified_inodes)
 			return -ENOMEM;
+		state->fc_modified_inodes_size +=
+			EXT4_FC_REPLAY_REALLOC_INCREMENT;
 	}
 	state->fc_modified_inodes[state->fc_modified_inodes_used++] = ino;
 	return 0;
@@ -1427,7 +1428,9 @@ static int ext4_fc_replay_inode(struct s
 	}
 	inode = NULL;
 
-	ext4_fc_record_modified_inode(sb, ino);
+	ret = ext4_fc_record_modified_inode(sb, ino);
+	if (ret)
+		goto out;
 
 	raw_fc_inode = (struct ext4_inode *)
 		(val + offsetof(struct ext4_fc_inode, fc_raw_inode));
@@ -1626,6 +1629,8 @@ static int ext4_fc_replay_add_range(stru
 	}
 
 	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
 
 	start = le32_to_cpu(ex->ee_block);
 	start_pblk = ext4_ext_pblock(ex);
@@ -1643,18 +1648,14 @@ static int ext4_fc_replay_add_range(stru
 		map.m_pblk = 0;
 		ret = ext4_map_blocks(NULL, inode, &map, 0);
 
-		if (ret < 0) {
-			iput(inode);
-			return 0;
-		}
+		if (ret < 0)
+			goto out;
 
 		if (ret == 0) {
 			/* Range is not mapped */
 			path = ext4_find_extent(inode, cur, NULL, 0);
-			if (IS_ERR(path)) {
-				iput(inode);
-				return 0;
-			}
+			if (IS_ERR(path))
+				goto out;
 			memset(&newex, 0, sizeof(newex));
 			newex.ee_block = cpu_to_le32(cur);
 			ext4_ext_store_pblock(
@@ -1668,10 +1669,8 @@ static int ext4_fc_replay_add_range(stru
 			up_write((&EXT4_I(inode)->i_data_sem));
 			ext4_ext_drop_refs(path);
 			kfree(path);
-			if (ret) {
-				iput(inode);
-				return 0;
-			}
+			if (ret)
+				goto out;
 			goto next;
 		}
 
@@ -1684,10 +1683,8 @@ static int ext4_fc_replay_add_range(stru
 			ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
 					ext4_ext_is_unwritten(ex),
 					start_pblk + cur - start);
-			if (ret) {
-				iput(inode);
-				return 0;
-			}
+			if (ret)
+				goto out;
 			/*
 			 * Mark the old blocks as free since they aren't used
 			 * anymore. We maintain an array of all the modified
@@ -1707,10 +1704,8 @@ static int ext4_fc_replay_add_range(stru
 			ext4_ext_is_unwritten(ex), map.m_pblk);
 		ret = ext4_ext_replay_update_ex(inode, cur, map.m_len,
 					ext4_ext_is_unwritten(ex), map.m_pblk);
-		if (ret) {
-			iput(inode);
-			return 0;
-		}
+		if (ret)
+			goto out;
 		/*
 		 * We may have split the extent tree while toggling the state.
 		 * Try to shrink the extent tree now.
@@ -1722,6 +1717,7 @@ next:
 	}
 	ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
 					sb->s_blocksize_bits);
+out:
 	iput(inode);
 	return 0;
 }
@@ -1751,6 +1747,8 @@ ext4_fc_replay_del_range(struct super_bl
 	}
 
 	ret = ext4_fc_record_modified_inode(sb, inode->i_ino);
+	if (ret)
+		goto out;
 
 	jbd_debug(1, "DEL_RANGE, inode %ld, lblk %d, len %d\n",
 			inode->i_ino, le32_to_cpu(lrange.fc_lblk),
@@ -1760,10 +1758,8 @@ ext4_fc_replay_del_range(struct super_bl
 		map.m_len = remaining;
 
 		ret = ext4_map_blocks(NULL, inode, &map, 0);
-		if (ret < 0) {
-			iput(inode);
-			return 0;
-		}
+		if (ret < 0)
+			goto out;
 		if (ret > 0) {
 			remaining -= ret;
 			cur += ret;
@@ -1778,15 +1774,13 @@ ext4_fc_replay_del_range(struct super_bl
 	ret = ext4_ext_remove_space(inode, lrange.fc_lblk,
 				lrange.fc_lblk + lrange.fc_len - 1);
 	up_write(&EXT4_I(inode)->i_data_sem);
-	if (ret) {
-		iput(inode);
-		return 0;
-	}
+	if (ret)
+		goto out;
 	ext4_ext_replay_shrink_inode(inode,
 		i_size_read(inode) >> sb->s_blocksize_bits);
 	ext4_mark_inode_dirty(NULL, inode);
+out:
 	iput(inode);
-
 	return 0;
 }