From e8e67bd4a4cabaae98dcbfac79c1d4b84066bf1c Mon Sep 17 00:00:00 2001 From: Anushree Prakash B Date: Thu, 26 Dec 2019 16:29:04 +0530 Subject: Bug#30689251 - BACKPORT TO MYSQL-5.6, BUG#29597896 - NULL POINTER DEREFERENCE IN LIBMYSQL DESCRIPTION: ============ There can be issues if the packets sent by the server are not proper. Certain checks should be performed at the client side while unpacking fields data. FIX: ==== Check for the appropriate fields data and error out if it is not present. RB: 23601 --- sql-common/client.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) (limited to 'sql-common') diff --git a/sql-common/client.c b/sql-common/client.c index c7fb70fbeef..22a4f789485 100644 --- a/sql-common/client.c +++ b/sql-common/client.c @@ -1538,9 +1538,23 @@ unpack_fields(MYSQL *mysql, MYSQL_DATA *data,MEM_ROOT *alloc,uint fields, { if (field - result >= fields) goto err; + + /* + If any of the row->data[] below is NULL, it can result in a + crash. Error out early as it indicates a malformed packet. + For data[0], data[1] and data[5], strmake_root will handle + NULL values. + */ + if (!row->data[2] || !row->data[3] || !row->data[4]) + { + free_rows(data); + set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate); + DBUG_RETURN(0); + } + cli_fetch_lengths(&lengths[0], row->data, default_value ? 6 : 5); - field->org_table= field->table= strdup_root(alloc,(char*) row->data[0]); - field->name= strdup_root(alloc,(char*) row->data[1]); + field->org_table= field->table= strmake_root(alloc,(char*) row->data[0], lengths[0]); + field->name= strmake_root(alloc,(char*) row->data[1], lengths[1]); field->length= (uint) uint3korr(row->data[2]); field->type= (enum enum_field_types) (uchar) row->data[3][0]; @@ -1565,7 +1579,7 @@ unpack_fields(MYSQL *mysql, MYSQL_DATA *data,MEM_ROOT *alloc,uint fields, field->flags|= NUM_FLAG; if (default_value && row->data[5]) { - field->def=strdup_root(alloc,(char*) row->data[5]); + field->def= strmake_root(alloc,(char*) row->data[5], lengths[5]); field->def_length= lengths[5]; } else -- cgit v1.2.1