good catch, thanks; I'll propagate this to our various OOB drivers.
-----Original Message----- From: Dan Carpenter [mailto:dan.carpen...@oracle.com] Sent: Wednesday, August 30, 2017 6:31 AM To: Dept-Eng QLA2xxx Upstream <qla2xxx-upstr...@cavium.com>; shqking <shqk...@gmail.com>; Carnuccio, Joe <joe.carnuc...@cavium.com> Cc: James E.J. Bottomley <j...@linux.vnet.ibm.com>; Martin K. Petersen <martin.peter...@oracle.com>; linux-scsi@vger.kernel.org; secur...@kernel.org Subject: [PATCH v2] scsi: qla2xxx: Fix an integer overflow in sysfs code 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: sta...@vger.kernel.org Fixes: b7cc176c9eb3 ("[SCSI] qla2xxx: Allow region-based flash-part accesses.") Reported-by: shqking <shqk...@gmail.com> Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com> --- 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);
