CaROS/meta-openembedded
3
1
Fork 0
mirror of git://git.openembedded.org/meta-openembedded synced 2026-01-01 13:58:06 +00:00
Code Issues Packages Projects Releases Wiki Activity

flatpak: patch CVE-2024-42472

Browse Source 
Details https://nvd.nist.gov/vuln/detail/CVE-2024-42472

Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>
This commit is contained in:
Ankur Tyagi 2025-12-16 12:43:28 +05:30 committed by Anuj Mittal
parent af50080591
commit d9148434ad
No known key found for this signature in database
GPG Key ID: 4340AEFE69F5085C
3 changed files with 215 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

169
meta-oe/recipes-extended/flatpak/flatpak/CVE-2024-42472_1.patch Normal file
View File

@ -0,0 +1,169 @@
From 2055273613350df0e6a7fa30d38d4ce6bc8079ca Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Mon, 3 Jun 2024 12:22:30 +0200
Subject: [PATCH] Don't follow symlinks when mounting persisted directories
These directories are in a location under application control, so we
can't trust them to not be a symlink outside of the files accessibe to
the application.
Continue to treat --persist=/foo as --persist=foo for backwards compat,
since this is how it (accidentally) worked before, but print a warning.
Don't allow ".." elements in persist paths: these would not be useful
anyway, and are unlikely to be in use, however they could potentially
be used to confuse the persist path handling.
This partially addresses CVE-2024-42472. If only one instance of the
malicious or compromised app is run at a time, the vulnerability
is avoided. If two instances can run concurrently, there is a
time-of-check/time-of-use issue remaining, which can only be resolved
with changes to bubblewrap; this will be resolved in a separate commit,
because the bubblewrap dependency might be more difficult to provide in
LTS distributions.
Helps: CVE-2024-42472, GHSA-7hgv-f2j8-xw87
[smcv: Make whitespace consistent]
[smcv: Use g_warning() if unable to create --persist paths]
[smcv: Use stat() to detect symlinks and warn about them]
Co-authored-by: Simon McVittie <smcv@collabora.com>
Signed-off-by: Simon McVittie <smcv@collabora.com>
CVE: CVE-2024-42472
Upstream-Status: Backport [https://github.com/flatpak/flatpak/commit/3caeb16c31a3ed62d744e2aaf01d684f7991051a]
(cherry picked from commit 3caeb16c31a3ed62d744e2aaf01d684f7991051a)
Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
---
common/flatpak-context.c | 109 +++++++++++++++++++++++++++++++++++++--
1 file changed, 105 insertions(+), 4 deletions(-)
diff --git a/common/flatpak-context.c b/common/flatpak-context.c
index 297a89ef..98dac5ee 100644
--- a/common/flatpak-context.c
+++ b/common/flatpak-context.c
@@ -2860,6 +2860,90 @@ flatpak_context_apply_env_appid (FlatpakBwrap *bwrap,
flatpak_bwrap_set_env (bwrap, "HOST_XDG_STATE_HOME", g_getenv ("XDG_STATE_HOME"), TRUE);
}
+/* This creates zero or more directories unders base_fd+basedir, each
+ * being guaranteed to either exist and be a directory (no symlinks)
+ * or be created as a directory. The last directory is opened
+ * and the fd is returned.
+ */
+static gboolean
+mkdir_p_open_nofollow_at (int base_fd,
+ const char *basedir,
+ int mode,
+ const char *subdir,
+ int *out_fd,
+ GError **error)
+{
+ glnx_autofd int parent_fd = -1;
+
+ if (g_path_is_absolute (subdir))
+ {
+ const char *skipped_prefix = subdir;
+
+ while (*skipped_prefix == '/')
+ skipped_prefix++;
+
+ g_warning ("--persist=\"%s\" is deprecated, treating it as --persist=\"%s\"", subdir, skipped_prefix);
+ subdir = skipped_prefix;
+ }
+
+ g_autofree char *subdir_dirname = g_path_get_dirname (subdir);
+
+ if (strcmp (subdir_dirname, ".") == 0)
+ {
+ /* It is ok to open basedir with follow=true */
+ if (!glnx_opendirat (base_fd, basedir, TRUE, &parent_fd, error))
+ return FALSE;
+ }
+ else if (strcmp (subdir_dirname, "..") == 0)
+ {
+ return glnx_throw (error, "'..' not supported in --persist paths");
+ }
+ else
+ {
+ if (!mkdir_p_open_nofollow_at (base_fd, basedir, mode,
+ subdir_dirname, &parent_fd, error))
+ return FALSE;
+ }
+
+ g_autofree char *subdir_basename = g_path_get_basename (subdir);
+
+ if (strcmp (subdir_basename, ".") == 0)
+ {
+ *out_fd = glnx_steal_fd (&parent_fd);
+ return TRUE;
+ }
+ else if (strcmp (subdir_basename, "..") == 0)
+ {
+ return glnx_throw (error, "'..' not supported in --persist paths");
+ }
+
+ if (!glnx_shutil_mkdir_p_at (parent_fd, subdir_basename, mode, NULL, error))
+ return FALSE;
+
+ int fd = openat (parent_fd, subdir_basename, O_PATH | O_NONBLOCK | O_DIRECTORY | O_CLOEXEC | O_NOCTTY | O_NOFOLLOW);
+ if (fd == -1)
+ {
+ int saved_errno = errno;
+ struct stat stat_buf;
+
+ /* If it's a symbolic link, that could be a user trying to offload
+ * large data to another filesystem, but it could equally well be
+ * a malicious or compromised app trying to exploit GHSA-7hgv-f2j8-xw87.
+ * Produce a clearer error message in this case.
+ * Unfortunately the errno we get in this case is ENOTDIR, so we have
+ * to ask again to find out whether it's really a symlink. */
+ if (saved_errno == ENOTDIR &&
+ fstatat (parent_fd, subdir_basename, &stat_buf, AT_SYMLINK_NOFOLLOW) == 0 &&
+ S_ISLNK (stat_buf.st_mode))
+ return glnx_throw (error, "Symbolic link \"%s\" not allowed to avoid sandbox escape", subdir_basename);
+
+ return glnx_throw_errno_prefix (error, "openat(%s)", subdir_basename);
+ }
+
+ *out_fd = fd;
+ return TRUE;
+}
+
void
flatpak_context_append_bwrap_filesystem (FlatpakContext *context,
FlatpakBwrap *bwrap,
@@ -2883,13 +2967,30 @@ flatpak_context_append_bwrap_filesystem (FlatpakContext *context,
while (g_hash_table_iter_next (&iter, &key, NULL))
{
const char *persist = key;
- g_autofree char *src = g_build_filename (g_get_home_dir (), ".var/app", app_id, persist, NULL);
+ g_autofree char *appdir = g_build_filename (g_get_home_dir (), ".var/app", app_id, NULL);
g_autofree char *dest = g_build_filename (g_get_home_dir (), persist, NULL);
+ g_autoptr(GError) local_error = NULL;
+
+ if (g_mkdir_with_parents (appdir, 0755) != 0)
+ {
+ g_warning ("Unable to create directory %s", appdir);
+ continue;
+ }
+
+ /* Don't follow symlinks from the persist directory, as it is under user control */
+ glnx_autofd int src_fd = -1;
+ if (!mkdir_p_open_nofollow_at (AT_FDCWD, appdir, 0755,
+ persist, &src_fd,
+ &local_error))
+ {
+ g_warning ("Failed to create persist path %s: %s", persist, local_error->message);
+ continue;
+ }
- if (g_mkdir_with_parents (src, 0755) != 0)
- g_info ("Unable to create directory %s", src);
+ g_autofree char *src_via_proc = g_strdup_printf ("/proc/self/fd/%d", src_fd);
- flatpak_bwrap_add_bind_arg (bwrap, "--bind", src, dest);
+ flatpak_bwrap_add_fd (bwrap, g_steal_fd (&src_fd));
+ flatpak_bwrap_add_bind_arg (bwrap, "--bind", src_via_proc, dest);
}
}

44
meta-oe/recipes-extended/flatpak/flatpak/CVE-2024-42472_2.patch Normal file
View File

@ -0,0 +1,44 @@
From dd8a68c126b8f73a58a37353b34ec25179859d79 Mon Sep 17 00:00:00 2001
From: Alexander Larsson <alexl@redhat.com>
Date: Tue, 18 Jun 2024 11:31:05 +0200
Subject: [PATCH] persist directories: Pass using new bwrap --bind-fd option
Instead of passing a /proc/self/fd bind mount we use --bind-fd, which
has two advantages:
* bwrap closes the fd when used, so it doesn't leak into the started app
* bwrap ensures that what was mounted was the passed in fd (same dev/ino),
as there is a small (required) gap between symlink resolve and mount
where the target path could be replaced.
Please note that this change requires an updated version of bubblewrap.
Resolves: CVE-2024-42472, GHSA-7hgv-f2j8-xw87
[smcv: Make whitespace consistent]
Co-authored-by: Simon McVittie <smcv@collabora.com>
Signed-off-by: Simon McVittie <smcv@collabora.com>
CVE: CVE-2024-42472
Upstream-Status: Backport [https://github.com/flatpak/flatpak/commit/6bd603f6836e9b38b9b937d3b78f3fbf36e7ff75]
(cherry picked from commit 6bd603f6836e9b38b9b937d3b78f3fbf36e7ff75)
Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
---
common/flatpak-context.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/common/flatpak-context.c b/common/flatpak-context.c
index 98dac5ee..24150daa 100644
--- a/common/flatpak-context.c
+++ b/common/flatpak-context.c
@@ -2987,10 +2987,10 @@ flatpak_context_append_bwrap_filesystem (FlatpakContext *context,
continue;
}
- g_autofree char *src_via_proc = g_strdup_printf ("/proc/self/fd/%d", src_fd);
+ g_autofree char *src_via_proc = g_strdup_printf ("%d", src_fd);
flatpak_bwrap_add_fd (bwrap, g_steal_fd (&src_fd));
- flatpak_bwrap_add_bind_arg (bwrap, "--bind", src_via_proc, dest);
+ flatpak_bwrap_add_bind_arg (bwrap, "--bind-fd", src_via_proc, dest);
}
}

2
meta-oe/recipes-extended/flatpak/flatpak_1.15.8.bb
View File

@ -6,6 +6,8 @@ LIC_FILES_CHKSUM = "file://COPYING;md5=4fbd65380cdd255951079008b364516c"
SRC_URI = " \
gitsm://github.com/flatpak/flatpak;protocol=https;branch=main \
file://0001-flatpak-pc-add-pc_sysrootdir.patch \
file://CVE-2024-42472_1.patch \
file://CVE-2024-42472_2.patch \
"
SRCREV = "925c80f913d69e7ca424428823e1431c4ffb0deb"