From patchwork Wed Aug 30 13:30:35 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v2] scsi: qla2xxx: Fix an integer overflow in sysfs code From: Dan Carpenter X-Patchwork-Id: 9929625 Message-Id: <20170830133035.nbkiled5hhdt26ui@mwanda> To: qla2xxx-upstream@qlogic.com, shqking , Joe Carnuccio Cc: "James E.J. Bottomley" , "Martin K. Petersen" , linux-scsi@vger.kernel.org, security@kernel.org Date: Wed, 30 Aug 2017 16:30:35 +0300 The value of "size" comes from the user. When we add "start + size" it could lead to an integer overflow bug. It means we vmalloc() a lot more memory than we had intended. I believe that on 64 bit systems vmalloc() can succeed even if we ask it to allocate huge 4GB buffers. So we would get memory corruption and likely a crash when we call ha->isp_ops->write_optrom() and ->read_optrom(). Only root can trigger this bug. Link: https://bugzilla.kernel.org/show_bug.cgi?id=194061 Cc: stable@vger.kernel.org Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part accesses.") Reported-by: shqking Signed-off-by: Dan Carpenter --- v2: Add stable and the URL for bugzila diff --git a/drivers/scsi/qla2xxx/qla_attr.c b/drivers/scsi/qla2xxx/qla_attr.c index 75c4b312645e..9ce28c4f9812 100644 --- a/drivers/scsi/qla2xxx/qla_attr.c +++ b/drivers/scsi/qla2xxx/qla_attr.c @@ -318,6 +318,8 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct kobject *kobj, return -EINVAL; if (start > ha->optrom_size) return -EINVAL; + if (size > ha->optrom_size - start) + size = ha->optrom_size - start; mutex_lock(&ha->optrom_mutex); switch (val) { @@ -343,8 +345,7 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct kobject *kobj, } ha->optrom_region_start = start; - ha->optrom_region_size = start + size > ha->optrom_size ? - ha->optrom_size - start : size; + ha->optrom_region_size = start + size; ha->optrom_state = QLA_SREADING; ha->optrom_buffer = vmalloc(ha->optrom_region_size); @@ -417,8 +418,7 @@ qla2x00_sysfs_write_optrom_ctl(struct file *filp, struct kobject *kobj, } ha->optrom_region_start = start; - ha->optrom_region_size = start + size > ha->optrom_size ? - ha->optrom_size - start : size; + ha->optrom_region_size = start + size; ha->optrom_state = QLA_SWRITING; ha->optrom_buffer = vmalloc(ha->optrom_region_size);