2012-06-07 09:08:03

by Marcus Meissner

Subject: [PATCH] tools/hv: Check the source of netlink messages to be the kernel

Hi,

The hyper-v userspace helper daemon receives and handles netlink
messages. It assumes them to be from the kernel, but does not check
that.

This patch adds this checking (nl_pid == 0).

CVE-2012-2669

Ciao, Marcus

Signed-off-by: Marcus Meissner <[email protected]>
Signed-off-by: Sebastian Krahmer <[email protected]>
Signed-off-by: Olaf Hering <[email protected]>
---
tools/hv/hv_kvp_daemon.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 146fd61..f0566c8 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -701,14 +701,16 @@ int main(void)
pfd.fd = fd;

while (1) {
+ struct sockaddr *addr_p = (struct sockaddr *) &addr;
+ socklen_t addr_l = sizeof(addr);
pfd.events = POLLIN;
pfd.revents = 0;
poll(&pfd, 1, -1);

- len = recv(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0);
+ len = recvfrom(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0, addr_p, &addr_l);

- if (len < 0) {
- syslog(LOG_ERR, "recv failed; error:%d", len);
+ if (len < 0 || addr.nl_pid) {
+ syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s", addr.nl_pid, errno, strerror(errno));
close(fd);
return -1;
}
--
1.7.9.2

2012-06-07 12:40:25

by KY Srinivasan

Subject: RE: [PATCH] tools/hv: Check the source of netlink messages to be the kernel

> -----Original Message-----
> From: Marcus Meissner [mailto:[email protected]]
> Sent: Thursday, June 07, 2012 5:08 AM
> To: [email protected]; KY Srinivasan; [email protected];
> Haiyang Zhang; [email protected]; [email protected];
> [email protected]
> Cc: Marcus Meissner; Sebastian Krahmer; Olaf Hering
> Subject: [PATCH] tools/hv: Check the source of netlink messages to be the kernel
>
> Hi,
>
> The hyper-v userspace helper daemon receives and handles netlink
> messages. It assumes them to be from the kernel, but does not check
> that.
>
> This patch adds this checking (nl_pid == 0).
>
> CVE-2012-2669
>
> Ciao, Marcus
>
> Signed-off-by: Marcus Meissner <[email protected]>
> Signed-off-by: Sebastian Krahmer <[email protected]>
> Signed-off-by: Olaf Hering <[email protected]>

Olaf already posted this patch and I signed off on it.

Regards,

K. Y
> ---
> tools/hv/hv_kvp_daemon.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
> index 146fd61..f0566c8 100644
> --- a/tools/hv/hv_kvp_daemon.c
> +++ b/tools/hv/hv_kvp_daemon.c
> @@ -701,14 +701,16 @@ int main(void)
> pfd.fd = fd;
>
> while (1) {
> + struct sockaddr *addr_p = (struct sockaddr *) &addr;
> + socklen_t addr_l = sizeof(addr);
> pfd.events = POLLIN;
> pfd.revents = 0;
> poll(&pfd, 1, -1);
>
> - len = recv(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0);
> + len = recvfrom(fd, kvp_recv_buffer, sizeof(kvp_recv_buffer), 0,
> addr_p, &addr_l);
>
> - if (len < 0) {
> - syslog(LOG_ERR, "recv failed; error:%d", len);
> + if (len < 0 || addr.nl_pid) {
> + syslog(LOG_ERR, "recvfrom failed; pid:%u error:%d %s",
> addr.nl_pid, errno, strerror(errno));
> close(fd);
> return -1;
> }
> --
> 1.7.9.2
>
>
>