From: Gustavo A. R. Silva Date: Thu, 16 Aug 2018 19:06:46 +0000 (-0500) Subject: switchtec: Fix Spectre v1 vulnerability X-Git-Tag: v4.19-rc4~30^2~4 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=46feb6b495f7628a6dbf36c4e6d80faf378372d4;p=linux.git switchtec: Fix Spectre v1 vulnerability p.port can 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/pci/switch/switchtec.c:912 ioctl_port_to_pff() warn: potential spectre issue 'pcfg->dsp_pff_inst_id' [r] Fix this by sanitizing p.port before using it to index pcfg->dsp_pff_inst_id 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 Signed-off-by: Gustavo A. R. Silva Signed-off-by: Bjorn Helgaas Acked-by: Logan Gunthorpe Cc: stable@vger.kernel.org --- diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 9940cc70f38b..54a8b30dda38 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -14,6 +14,8 @@ #include #include +#include + MODULE_DESCRIPTION("Microsemi Switchtec(tm) PCIe Management Driver"); MODULE_VERSION("0.1"); MODULE_LICENSE("GPL"); @@ -909,6 +911,8 @@ static int ioctl_port_to_pff(struct switchtec_dev *stdev, default: if (p.port > ARRAY_SIZE(pcfg->dsp_pff_inst_id)) return -EINVAL; + p.port = array_index_nospec(p.port, + ARRAY_SIZE(pcfg->dsp_pff_inst_id) + 1); p.pff = ioread32(&pcfg->dsp_pff_inst_id[p.port - 1]); break; }