diff options
Diffstat (limited to 'init')
| -rw-r--r-- | init/devices.c | 34 |
1 files changed, 29 insertions, 5 deletions
diff --git a/init/devices.c b/init/devices.c index eb5d84e..e73efdf 100644 --- a/init/devices.c +++ b/init/devices.c @@ -33,8 +33,6 @@ #include <asm/page.h> #include <sys/wait.h> -#include <cutils/uevent.h> - #include "devices.h" #include "util.h" #include "log.h" @@ -591,9 +589,35 @@ static void handle_firmware_event(struct uevent *uevent) #define UEVENT_MSG_LEN 1024 void handle_device_fd() { - char msg[UEVENT_MSG_LEN+2]; - int n; - while ((n = uevent_checked_recv(device_fd, msg, UEVENT_MSG_LEN)) > 0) { + for(;;) { + char msg[UEVENT_MSG_LEN+2]; + char cred_msg[CMSG_SPACE(sizeof(struct ucred))]; + struct iovec iov = {msg, sizeof(msg)}; + struct sockaddr_nl snl; + struct msghdr hdr = {&snl, sizeof(snl), &iov, 1, cred_msg, sizeof(cred_msg), 0}; + + ssize_t n = recvmsg(device_fd, &hdr, 0); + if (n <= 0) { + break; + } + + if ((snl.nl_groups != 1) || (snl.nl_pid != 0)) { + /* ignoring non-kernel netlink multicast message */ + continue; + } + + struct cmsghdr * cmsg = CMSG_FIRSTHDR(&hdr); + if (cmsg == NULL || cmsg->cmsg_type != SCM_CREDENTIALS) { + /* no sender credentials received, ignore message */ + continue; + } + + struct ucred * cred = (struct ucred *)CMSG_DATA(cmsg); + if (cred->uid != 0) { + /* message from non-root user, ignore */ + continue; + } + if(n >= UEVENT_MSG_LEN) /* overflow -- discard */ continue; |