4.4-stable review patch. If anyone has any objections, please let me know.
------------------ From: Dan Carpenter <dan.carpen...@oracle.com> commit e6f77540c067b48dee10f1e33678415bfcc89017 upstream. 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 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> Signed-off-by: Martin K. Petersen <martin.peter...@oracle.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/scsi/qla2xxx/qla_attr.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/drivers/scsi/qla2xxx/qla_attr.c +++ b/drivers/scsi/qla2xxx/qla_attr.c @@ -404,6 +404,8 @@ qla2x00_sysfs_write_optrom_ctl(struct fi 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) { @@ -429,8 +431,7 @@ qla2x00_sysfs_write_optrom_ctl(struct fi } 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); @@ -503,8 +504,7 @@ qla2x00_sysfs_write_optrom_ctl(struct fi } 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);
