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MDEV-30023 Revoking Privilege on the Column Yields the Error

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The change from MDEV-29465 exposed a flaw in replace_column_table
where again we were not properly updating the column-level bits.

replace_table_table was changed in MDEV-29465 to properly update
grant_table->init_cols, however replace_column_table still only
modified grant_column->rights when the GRANT_COLUMN already existed.

This lead to a missmatch between GRANT_COLUMN::init_rights and
GRANT_COLUMN::rights, *if* the GRANT_COLUMN already existed.

As an example:

GRANT SELECT (col1) ...
Here:
For col1
GRANT_COLUMN::init_rights and GRANT_COLUMN::rights are set to 1 (SELECT) in
replace_column_table.

GRANT INSERT (col1) ...
Here, without this patch GRANT_COLUMN::init_rights is still 1 and
GRANT_COLUMN::rights is 3 (SELECT_PRIV | INSERT_PRIV)

Finally, if before this patch, one does:

REVOKE SELECT (col1) ...

replace_table_table will see that init_rights loses bit 1 thus it
considers there are no more rights granted on that particular table.

This prompts the whole GRANT_TABLE to be removed via the first revoke,
when the GRANT_COLUMN corresponding to it should still have init_rights == 2.

By also updating replace_column_table to keep init_rights in sync
properly, the issue is resolved.

Reviewed by <serg@mariadb.com>
This commit is contained in:
Vicențiu Ciorbaru
2022-11-24 19:50:14 +02:00
parent 6c973be2e9
commit b527bfe823
3 changed files with 48 additions and 2 deletions
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7
sql/sql_acl.cc
View File

@ -5148,8 +5148,11 @@ static int replace_column_table(GRANT_TABLE *g_t,
error= 0;
grant_column= column_hash_search(g_t, column->column.ptr(),
column->column.length());
if (grant_column) // Should always be true
grant_column->rights= privileges; // Update hash
if (grant_column) // Should always be true
{
grant_column->rights= privileges; // Update hash
grant_column->init_rights= privileges;
}
}
else // new grant
{