xf86drm: Check non-absolute path only for virtio based devices

This fixes bug in drmParseSubsystemType() that cases situation when
subsequent call to readlink() from get_subsystem_type() will result in
EACCESS.

Signed-off-by: Mikhail Golubev <mikhail.golubev@opensynergy.com>
main
Mikhail Golubev 2020-04-20 20:08:50 +02:00 committed by Emil Velikov
parent 9001c93b7f
commit 57df07572c
1 changed files with 8 additions and 4 deletions

View File

@ -3103,14 +3103,17 @@ static int drmParseSubsystemType(int maj, int min)
int subsystem_type;
snprintf(path, sizeof(path), "/sys/dev/char/%d:%d/device", maj, min);
if (!realpath(path, real_path))
return -errno;
snprintf(path, sizeof(path), "%s", real_path);
subsystem_type = get_subsystem_type(path);
/* Try to get the parent (underlying) device type */
if (subsystem_type == DRM_BUS_VIRTIO) {
/* Assume virtio-pci on error */
if (!realpath(path, real_path))
return DRM_BUS_VIRTIO;
strncat(path, "/..", PATH_MAX);
subsystem_type = get_subsystem_type(path);
if (subsystem_type < 0)
return DRM_BUS_VIRTIO;
}
return subsystem_type;
#elif defined(__OpenBSD__) || defined(__DragonFly__) || defined(__FreeBSD__)
@ -3920,6 +3923,7 @@ process_device(drmDevicePtr *device, const char *d_name,
switch (subsystem_type) {
case DRM_BUS_PCI:
case DRM_BUS_VIRTIO:
return drmProcessPciDevice(device, node, node_type, maj, min,
fetch_deviceinfo, flags);
case DRM_BUS_USB: