Bug#975875: x11vnc: CVE-2020-29074
Control: tags -1 + patch
Hi
On Thu, Nov 26, 2020 at 05:59:50AM +0100, Salvatore Bonaccorso wrote:
> Source: x11vnc
> Version: 0.9.13-6
> Severity: grave
> Tags: security upstream fixed-upstream
> Justification: user security hole
> X-Debbugs-Cc: carnil@debian.org, Debian Security Team <team@security.debian.org>
> Control: found -1 0.9.16-4
>
> Hi,
>
> The following vulnerability was published for x11vnc.
>
> CVE-2020-29074[0]:
> | scan.c in x11vnc 0.9.16 uses IPC_CREAT|0777 in shmget calls, which
> | allows access by actors other than the current user.
>
>
> If you fix the vulnerability please also make sure to include the
> CVE (Common Vulnerabilities & Exposures) id in your changelog entry.
>
> For further information see:
>
> [0] https://security-tracker.debian.org/tracker/CVE-2020-29074
> https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-29074
> [1] https://github.com/LibVNC/x11vnc/commit/69eeb9f7baa14ca03b16c9de821f9876def7a36a
>
> Given the relative minor change I have already picked up the commit
> for a buster-security update as well.
For unstable I openend
https://salsa.debian.org/debian-remote-team/x11vnc/-/merge_requests/2
Regards,
Salvatore
From: =?UTF-8?q?Gu=C3=A9nal=20DAVALAN?= <guenal.davalan@uca.fr>
Date: Wed, 18 Nov 2020 08:40:45 +0100
Subject: scan: limit access to shared memory segments to current user
Origin: https://github.com/LibVNC/x11vnc/commit/69eeb9f7baa14ca03b16c9de821f9876def7a36a
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2020-29074
Bug-Debian: https://bugs.debian.org/975875
---
src/scan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/scan.c b/src/scan.c
index 43e00d20aaae..12994d521f22 100644
--- a/src/scan.c
+++ b/src/scan.c
@@ -320,7 +320,7 @@ static int shm_create(XShmSegmentInfo *shm, XImage **ximg_ptr, int w, int h,
#if HAVE_XSHM
shm->shmid = shmget(IPC_PRIVATE,
- xim->bytes_per_line * xim->height, IPC_CREAT | 0777);
+ xim->bytes_per_line * xim->height, IPC_CREAT | 0600);
if (shm->shmid == -1) {
rfbErr("shmget(%s) failed.\n", name);
--
2.20.1
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