ext4: fix error handling in ext4_fc_record_modified_inode()

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

diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index ccd2b216d6ba143eff93b28c12d348b2ea1d5ee9..5934c23e153e59f3c769ce94e4ebcbf511973059 100644 (file)
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -1410,14 +1410,15 @@ static int ext4_fc_record_modified_inode(struct super_block *sb, int ino)
                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;
@@ -1449,7 +1450,9 @@ static int ext4_fc_replay_inode(struct super_block *sb, struct ext4_fc_tl *tl,
        }
        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));
@@ -1649,6 +1652,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
        }
 
        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);
@@ -1666,18 +1671,14 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
                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(
@@ -1691,10 +1692,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
                        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;
                }
 
@@ -1707,10 +1706,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
                        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
@@ -1730,10 +1727,8 @@ static int ext4_fc_replay_add_range(struct super_block *sb,
                        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.
@@ -1745,6 +1740,7 @@ next:
        }
        ext4_ext_replay_shrink_inode(inode, i_size_read(inode) >>
                                        sb->s_blocksize_bits);
+out:
        iput(inode);
        return 0;
 }
@@ -1774,6 +1770,8 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
        }
 
        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),
@@ -1783,10 +1781,8 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
                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;
@@ -1801,15 +1797,13 @@ ext4_fc_replay_del_range(struct super_block *sb, struct ext4_fc_tl *tl,
        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;
 }