[Buildroot] [PATCH 1/1] package/x11vnc: fix CVE-2020-29074

* [Buildroot] [PATCH 1/1] package/x11vnc: fix CVE-2020-29074
@ 2020-12-03 20:10 Fabrice Fontaine
  2020-12-05 20:32 ` Thomas Petazzoni
  2020-12-12 11:04 ` Peter Korsgaard
  0 siblings, 2 replies; 3+ messages in thread
From: Fabrice Fontaine @ 2020-12-03 20:10 UTC (permalink / raw)
  To: buildroot

scan.c in x11vnc 0.9.16 uses IPC_CREAT|0777 in shmget calls, which
allows access by actors other than the current user.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
 ...ared-memory-segments-to-current-user.patch | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 package/x11vnc/0002-scan-limit-access-to-shared-memory-segments-to-current-user.patch

diff --git a/package/x11vnc/0002-scan-limit-access-to-shared-memory-segments-to-current-user.patch b/package/x11vnc/0002-scan-limit-access-to-shared-memory-segments-to-current-user.patch
new file mode 100644
index 0000000000..e4dbdf1894
--- /dev/null
+++ b/package/x11vnc/0002-scan-limit-access-to-shared-memory-segments-to-current-user.patch
@@ -0,0 +1,25 @@
+From 69eeb9f7baa14ca03b16c9de821f9876def7a36a Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Gu=C3=A9nal=20DAVALAN?= <guenal.davalan@uca.fr>
+Date: Wed, 18 Nov 2020 08:40:45 +0100
+Subject: [PATCH] scan: limit access to shared memory segments to current user
+
+[Retrieved from:
+https://github.com/LibVNC/x11vnc/commit/69eeb9f7baa14ca03b16c9de821f9876def7a36a]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ src/scan.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/scan.c b/src/scan.c
+index 43e00d2..12994d5 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);
-- 
2.29.2

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