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package/gvfs: fix CVE-2019-12447

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An issue was discovered in GNOME gvfs 1.29.4 through 1.41.2.
daemon/gvfsbackendadmin.c mishandles file ownership because setfsuid is
not used.

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>
This commit is contained in:
Fabrice Fontaine 2020-03-29 18:02:44 +02:00 committed by Yann E. MORIN
parent e49aa31f5c
commit 062d0f6913
3 changed files with 129 additions and 0 deletions
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34
package/gvfs/0003-admin-Allow-changing-file-owner.patch Normal file
View File

@ -0,0 +1,34 @@
From daf1163aba229afcfddf0f925aef7e97047e8959 Mon Sep 17 00:00:00 2001
From: Ondrej Holy <oholy@redhat.com>
Date: Thu, 23 May 2019 10:29:08 +0200
Subject: [PATCH] admin: Allow changing file owner
CAP_CHOWN is dropped together with other privilages and thus the backend
can't change file owner. This might be probably e.g. in case of copy
operation when G_FILE_COPY_ALL_METADATA is used. Let's keep CAP_CHOWN
to fix this.
[Retrieved from:
https://gitlab.gnome.org/GNOME/gvfs/commit/daf1163aba229afcfddf0f925aef7e97047e8959]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
daemon/gvfsbackendadmin.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/daemon/gvfsbackendadmin.c b/daemon/gvfsbackendadmin.c
index 23d16f16..a74d09cf 100644
--- a/daemon/gvfsbackendadmin.c
+++ b/daemon/gvfsbackendadmin.c
@@ -968,7 +968,8 @@ g_vfs_backend_admin_init (GVfsBackendAdmin *self)
#define REQUIRED_CAPS (CAP_TO_MASK(CAP_FOWNER) | \
CAP_TO_MASK(CAP_DAC_OVERRIDE) | \
- CAP_TO_MASK(CAP_DAC_READ_SEARCH))
+ CAP_TO_MASK(CAP_DAC_READ_SEARCH) | \
+ CAP_TO_MASK(CAP_CHOWN))
static void
acquire_caps (uid_t uid)
--
2.24.1

91
package/gvfs/0004-admin-Use-fsuid-to-ensure-correct-file-ownership.patch Normal file
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@ -0,0 +1,91 @@
From 3895e09d784ebec0fbc4614d5c37068736120e1d Mon Sep 17 00:00:00 2001
From: Ondrej Holy <oholy@redhat.com>
Date: Thu, 23 May 2019 10:33:30 +0200
Subject: [PATCH] admin: Use fsuid to ensure correct file ownership
Files created over admin backend should be owned by root, but they are
owned by the user itself. This is because the daemon drops the uid to
make dbus connection work. Use fsuid and euid to fix this issue.
Closes: https://gitlab.gnome.org/GNOME/gvfs/issues/21
[Retrieved from:
https://gitlab.gnome.org/GNOME/gvfs/commit/3895e09d784ebec0fbc4614d5c37068736120e1d]
Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
---
daemon/gvfsbackendadmin.c | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)
diff --git a/daemon/gvfsbackendadmin.c b/daemon/gvfsbackendadmin.c
index a74d09cf..32b51b1a 100644
--- a/daemon/gvfsbackendadmin.c
+++ b/daemon/gvfsbackendadmin.c
@@ -157,19 +157,6 @@ complete_job (GVfsJob *job,
g_vfs_job_succeeded (job);
}
-static void
-fix_file_info (GFileInfo *info)
-{
- /* Override read/write flags, since the above call will use access()
- * to determine permissions, which does not honor our privileged
- * capabilities.
- */
- g_file_info_set_attribute_boolean (info, G_FILE_ATTRIBUTE_ACCESS_CAN_READ, TRUE);
- g_file_info_set_attribute_boolean (info, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE, TRUE);
- g_file_info_set_attribute_boolean (info, G_FILE_ATTRIBUTE_ACCESS_CAN_DELETE, TRUE);
- g_file_info_set_attribute_boolean (info, G_FILE_ATTRIBUTE_ACCESS_CAN_RENAME, TRUE);
-}
-
static void
do_query_info (GVfsBackend *backend,
GVfsJobQueryInfo *query_info_job,
@@ -195,7 +182,6 @@ do_query_info (GVfsBackend *backend,
if (error != NULL)
goto out;
- fix_file_info (real_info);
g_file_info_copy_into (real_info, info);
g_object_unref (real_info);
@@ -220,7 +206,6 @@ do_query_info_on_read (GVfsBackend *backend,
if (error != NULL)
goto out;
- fix_file_info (real_info);
g_file_info_copy_into (real_info, info);
g_object_unref (real_info);
@@ -245,7 +230,6 @@ do_query_info_on_write (GVfsBackend *backend,
if (error != NULL)
goto out;
- fix_file_info (real_info);
g_file_info_copy_into (real_info, info);
g_object_unref (real_info);
@@ -977,14 +961,15 @@ acquire_caps (uid_t uid)
struct __user_cap_header_struct hdr;
struct __user_cap_data_struct data;
- /* Tell kernel not clear capabilities when dropping root */
- if (prctl (PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0)
- g_error ("prctl(PR_SET_KEEPCAPS) failed");
-
- /* Drop root uid, but retain the required permitted caps */
- if (setuid (uid) < 0)
+ /* Set euid to user to make dbus work */
+ if (seteuid (uid) < 0)
g_error ("unable to drop privs");
+ /* Set fsuid to still behave like root when working with files */
+ setfsuid (0);
+ if (setfsuid (-1) != 0)
+ g_error ("setfsuid failed");
+
memset (&hdr, 0, sizeof(hdr));
hdr.version = _LINUX_CAPABILITY_VERSION;
--
2.24.1

4
package/gvfs/gvfs.mk
View File

@ -21,6 +21,10 @@ GVFS_IGNORE_CVES += CVE-2019-3827
# package/gvfs/0002-admin-Add-query_info_on_read-write-functionality.patch
GVFS_IGNORE_CVES += CVE-2019-12448
# 0003-admin-Allow-changing-file-owner.patch
# 0004-admin-Use-fsuid-to-ensure-correct-file-ownership.patch
GVFS_IGNORE_CVES += CVE-2019-12447
# Export ac_cv_path_LIBGCRYPT_CONFIG unconditionally to prevent
# build system from searching the host paths.
GVFS_CONF_ENV = \