karg->hdr.port is indirectly controlled by user-space, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. This issue was detected with the help of Smatch: drivers/message/fusion/mptctl.c:1360 mptctl_getiocinfo() warn: potential spectre issue 'ioc->pfacts' [r] Fix this by sanitizing karg->hdr.port before indirectly using it to index ioc->pfacts Notice that given that speculation windows are large, the policy is to kill the speculation on the first load and not worry if it can be completed with a dependent load/store [1]. [1] https://marc.info/?l=linux-kernel&m=152449131114778&w=2 Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx> --- Notice that the '1 + 1' thing is intentional for clarity purposes. drivers/message/fusion/mptctl.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/message/fusion/mptctl.c b/drivers/message/fusion/mptctl.c index 8d22d61..afc6979 100644 --- a/drivers/message/fusion/mptctl.c +++ b/drivers/message/fusion/mptctl.c @@ -59,6 +59,7 @@ #include <asm/io.h> #include <linux/uaccess.h> +#include <linux/nospec.h> #include <scsi/scsi.h> #include <scsi/scsi_cmnd.h> @@ -1306,7 +1307,7 @@ mptctl_getiocinfo (unsigned long arg, unsigned int data_size) kfree(karg); return -EINVAL; } - port = karg->hdr.port; + port = array_index_nospec(karg->hdr.port, 1 + 1); karg->port = port; pdev = (struct pci_dev *) ioc->pcidev; -- 2.7.4
