vfio: Fix overrun after readlink() fills buffer completely
readlink() returns the number of bytes written to the buffer, and it
doesn't write a terminating null byte. vfio_init() writes it itself.
Overruns the buffer when readlink() filled it completely.
Fix by treating readlink() filling the buffer completely as error,
like we do in pci-assign.c's assign_failed_examine().
Spotted by Coverity.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
diff --git a/hw/misc/vfio.c b/hw/misc/vfio.c
index 8db182f..e669bbe 100644
--- a/hw/misc/vfio.c
+++ b/hw/misc/vfio.c
@@ -3681,10 +3681,10 @@
strncat(path, "iommu_group", sizeof(path) - strlen(path) - 1);
- len = readlink(path, iommu_group_path, PATH_MAX);
- if (len <= 0) {
+ len = readlink(path, iommu_group_path, sizeof(path));
+ if (len <= 0 || len >= sizeof(path)) {
error_report("vfio: error no iommu_group for device");
- return -errno;
+ return len < 0 ? -errno : ENAMETOOLONG;
}
iommu_group_path[len] = 0;
