[dpdk-dev] [RFC 2/5] bus/pci: fix TOCTOU issue
Stephen Hemminger
stephen at networkplumber.org
Tue Nov 6 22:48:58 CET 2018
Using access followed by open causes a static analysis warning
about Time of check versus Time of use. Also, access() and
open() have different UID permission checks.
This is not a serious problem; but easy to fix by using errno instead.
Coverity issue: 300870
Fixes: 4a928ef9f611 ("bus/pci: enable write combining during mapping")
Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
drivers/bus/pci/linux/pci_uio.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
index 112ac51dddcc..8521fe63b0ae 100644
--- a/drivers/bus/pci/linux/pci_uio.c
+++ b/drivers/bus/pci/linux/pci_uio.c
@@ -306,12 +306,11 @@ pci_uio_map_resource_by_index(struct rte_pci_device *dev, int res_idx,
loc->domain, loc->bus, loc->devid,
loc->function, res_idx);
- if (access(devname, R_OK|W_OK) != -1) {
- fd = open(devname, O_RDWR);
- if (fd < 0)
- RTE_LOG(INFO, EAL, "%s cannot be mapped. "
- "Fall-back to non prefetchable mode.\n",
- devname);
+ fd = open(devname, O_RDWR);
+ if (fd < 0 && errno != ENOENT) {
+ RTE_LOG(INFO, EAL, "%s cannot be mapped. "
+ "Fall-back to non prefetchable mode.\n",
+ devname);
}
}
--
2.17.1
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