systemd: Fix CVE-2021-3997

Add patches to fix CVE-2021-3997.

Add additional below mentioned patches which are
required to fix CVE:
1. rm-rf-optionally-fsync-after-removing-directory-tree.patch
2. rm-rf-refactor-rm-rf-children-split-out-body-of-directory.patch
Link: http://archive.ubuntu.com/ubuntu/pool/main/s/systemd/systemd_245.4-4ubuntu3.15.debian.tar.xz

Signed-off-by: Purushottam Choudhary <purushottam.choudhary@kpit.com>
Signed-off-by: Purushottam Choudhary <purushottamchoudhary29@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

1 files changed, 318 insertions, 0 deletions

diff --git a/meta/recipes-core/systemd/systemd/rm-rf-refactor-rm-rf-children-split-out-body-of-directory.patch b/meta/recipes-core/systemd/systemd/rm-rf-refactor-rm-rf-children-split-out-body-of-directory.patch
new file mode 100644
index 0000000000..f80e6433c6
--- /dev/null
+++ b/meta/recipes-core/systemd/systemd/rm-rf-refactor-rm-rf-children-split-out-body-of-directory.patch
@@ -0,0 +1,318 @@
+Backport of the following upstream commit:
+From 96906b22417c65d70933976e0ee920c70c9113a4 Mon Sep 17 00:00:00 2001
+From: Lennart Poettering <lennart@poettering.net>
+Date: Tue, 26 Jan 2021 16:30:06 +0100
+Subject: [PATCH] rm-rf: refactor rm_rf_children(), split out body of directory
+ iteration loop
+
+This splits out rm_rf_children_inner() as body of the loop. We can use
+that to implement rm_rf_child() for deleting one specific entry in a
+directory.
+
+Upstream-Status: Backport [http://archive.ubuntu.com/ubuntu/pool/main/s/systemd/systemd_245.4-4ubuntu3.15.debian.tar.xz]
+Signed-off-by: Purushottam Choudhary <Purushottam.Choudhary@kpit.com>
+---
+ src/basic/rm-rf.c | 223 ++++++++++++++++++++++++++-------------------
+ src/basic/rm-rf.h |   3 +-
+ 2 files changed, 131 insertions(+), 95 deletions(-)
+
+--- a/src/basic/rm-rf.c
++++ b/src/basic/rm-rf.c
+@@ -19,138 +19,153 @@
+ #include "stat-util.h"
+ #include "string-util.h"
+ 
++/* We treat tmpfs/ramfs + cgroupfs as non-physical file sytems. cgroupfs is similar to tmpfs in a way after
++ * all: we can create arbitrary directory hierarchies in it, and hence can also use rm_rf() on it to remove
++ * those again. */
+ static bool is_physical_fs(const struct statfs *sfs) {
+         return !is_temporary_fs(sfs) && !is_cgroup_fs(sfs);
+ }
+ 
+-int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev) {
++static int rm_rf_children_inner(
++                int fd,
++                const char *fname,
++                int is_dir,
++                RemoveFlags flags,
++                const struct stat *root_dev) {
++
++        struct stat st;
++        int r;
++
++        assert(fd >= 0);
++        assert(fname);
++
++        if (is_dir < 0 || (is_dir > 0 && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
++
++                r = fstatat(fd, fname, &st, AT_SYMLINK_NOFOLLOW);
++                if (r < 0)
++                        return r;
++
++                is_dir = S_ISDIR(st.st_mode);
++        }
++
++        if (is_dir) {
++                _cleanup_close_ int subdir_fd = -1;
++                int q;
++
++                /* if root_dev is set, remove subdirectories only if device is same */
++                if (root_dev && st.st_dev != root_dev->st_dev)
++                        return 0;
++
++                /* Stop at mount points */
++                r = fd_is_mount_point(fd, fname, 0);
++                if (r < 0)
++                        return r;
++                if (r > 0)
++                        return 0;
++
++                if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
++
++                        /* This could be a subvolume, try to remove it */
++
++                        r = btrfs_subvol_remove_fd(fd, fname, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
++                        if (r < 0) {
++                                if (!IN_SET(r, -ENOTTY, -EINVAL))
++                                        return r;
++
++                                /* ENOTTY, then it wasn't a btrfs subvolume, continue below. */
++                        } else
++                                /* It was a subvolume, done. */
++                                return 1;
++                }
++
++                subdir_fd = openat(fd, fname, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
++                if (subdir_fd < 0)
++                        return -errno;
++
++                /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file system type
++                 * again for each directory */
++                q = rm_rf_children(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev);
++
++                r = unlinkat(fd, fname, AT_REMOVEDIR);
++                if (r < 0)
++                        return r;
++                if (q < 0)
++                        return q;
++
++                return 1;
++
++        } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
++                r = unlinkat(fd, fname, 0);
++                if (r < 0)
++                        return r;
++
++                return 1;
++        }
++
++        return 0;
++}
++
++int rm_rf_children(
++                int fd,
++                RemoveFlags flags,
++                const struct stat *root_dev) {
++
+         _cleanup_closedir_ DIR *d = NULL;
+         struct dirent *de;
+         int ret = 0, r;
+-        struct statfs sfs;
+ 
+         assert(fd >= 0);
+ 
+         /* This returns the first error we run into, but nevertheless tries to go on. This closes the passed
+-         * fd, in all cases, including on failure.. */
++         * fd, in all cases, including on failure. */
++
++        d = fdopendir(fd);
++        if (!d) {
++                safe_close(fd);
++                return -errno;
++        }
+ 
+         if (!(flags & REMOVE_PHYSICAL)) {
++                struct statfs sfs;
+ 
+-                r = fstatfs(fd, &sfs);
+-                if (r < 0) {
+-                        safe_close(fd);
++                if (fstatfs(dirfd(d), &sfs) < 0)
+                         return -errno;
+                 }
+ 
+                 if (is_physical_fs(&sfs)) {
+-                        /* We refuse to clean physical file systems with this call,
+-                         * unless explicitly requested. This is extra paranoia just
+-                         * to be sure we never ever remove non-state data. */
++                        /* We refuse to clean physical file systems with this call, unless explicitly
++                         * requested. This is extra paranoia just to be sure we never ever remove non-state
++                         * data. */
++
+                         _cleanup_free_ char *path = NULL;
+ 
+                         (void) fd_get_path(fd, &path);
+-                        log_error("Attempted to remove disk file system under \"%s\", and we can't allow that.",
+-                                  strna(path));
+-
+-                        safe_close(fd);
+-                        return -EPERM;
++                        return log_error_errno(SYNTHETIC_ERRNO(EPERM),
++                                               "Attempted to remove disk file system under \"%s\", and we can't allow that.",
++                                               strna(path));
+                 }
+         }
+ 
+-        d = fdopendir(fd);
+-        if (!d) {
+-                safe_close(fd);
+-                return errno == ENOENT ? 0 : -errno;
+-        }
+-
+         FOREACH_DIRENT_ALL(de, d, return -errno) {
+-                bool is_dir;
+-                struct stat st;
++                int is_dir;
+ 
+                 if (dot_or_dot_dot(de->d_name))
+                         continue;
+ 
+-                if (de->d_type == DT_UNKNOWN ||
+-                    (de->d_type == DT_DIR && (root_dev || (flags & REMOVE_SUBVOLUME)))) {
+-                        if (fstatat(fd, de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0) {
+-                                if (ret == 0 && errno != ENOENT)
+-                                        ret = -errno;
+-                                continue;
+-                        }
+-
+-                        is_dir = S_ISDIR(st.st_mode);
+-                } else
+-                        is_dir = de->d_type == DT_DIR;
+-
+-                if (is_dir) {
+-                        _cleanup_close_ int subdir_fd = -1;
+-
+-                        /* if root_dev is set, remove subdirectories only if device is same */
+-                        if (root_dev && st.st_dev != root_dev->st_dev)
+-                                continue;
+-
+-                        subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME);
+-                        if (subdir_fd < 0) {
+-                                if (ret == 0 && errno != ENOENT)
+-                                        ret = -errno;
+-                                continue;
+-                        }
+-
+-                        /* Stop at mount points */
+-                        r = fd_is_mount_point(fd, de->d_name, 0);
+-                        if (r < 0) {
+-                                if (ret == 0 && r != -ENOENT)
+-                                        ret = r;
+-
+-                                continue;
+-                        }
+-                        if (r > 0)
+-                                continue;
+-
+-                        if ((flags & REMOVE_SUBVOLUME) && st.st_ino == 256) {
+-
+-                                /* This could be a subvolume, try to remove it */
+-
+-                                r = btrfs_subvol_remove_fd(fd, de->d_name, BTRFS_REMOVE_RECURSIVE|BTRFS_REMOVE_QUOTA);
+-                                if (r < 0) {
+-                                        if (!IN_SET(r, -ENOTTY, -EINVAL)) {
+-                                                if (ret == 0)
+-                                                        ret = r;
+-
+-                                                continue;
+-                                        }
+-
+-                                        /* ENOTTY, then it wasn't a btrfs subvolume, continue below. */
+-                                } else
+-                                        /* It was a subvolume, continue. */
+-                                        continue;
+-                        }
+-
+-                        /* We pass REMOVE_PHYSICAL here, to avoid doing the fstatfs() to check the file
+-                         * system type again for each directory */
+-                        r = rm_rf_children(TAKE_FD(subdir_fd), flags | REMOVE_PHYSICAL, root_dev);
+-                        if (r < 0 && ret == 0)
+-                                ret = r;
+-
+-                        if (unlinkat(fd, de->d_name, AT_REMOVEDIR) < 0) {
+-                                if (ret == 0 && errno != ENOENT)
+-                                        ret = -errno;
+-                        }
+-
+-                } else if (!(flags & REMOVE_ONLY_DIRECTORIES)) {
+-
+-                        if (unlinkat(fd, de->d_name, 0) < 0) {
+-                                if (ret == 0 && errno != ENOENT)
+-                                        ret = -errno;
+-                        }
+-                }
++                is_dir =
++                        de->d_type == DT_UNKNOWN ? -1 :
++                        de->d_type == DT_DIR;
++
++                r = rm_rf_children_inner(dirfd(d), de->d_name, is_dir, flags, root_dev);
++                if (r < 0 && r != -ENOENT && ret == 0)
++                        ret = r;
+         }
++
+         return ret;
+ }
+ 
+ int rm_rf(const char *path, RemoveFlags flags) {
+         int fd, r;
+-        struct statfs s;
+ 
+         assert(path);
+ 
+@@ -195,9 +210,10 @@
+                 if (FLAGS_SET(flags, REMOVE_ROOT)) {
+ 
+                         if (!FLAGS_SET(flags, REMOVE_PHYSICAL)) {
++                                struct statfs s;
++
+                                 if (statfs(path, &s) < 0)
+                                         return -errno;
+-
+                                 if (is_physical_fs(&s))
+                                         return log_error_errno(SYNTHETIC_ERRNO(EPERM),
+                                                                "Attempted to remove files from a disk file system under \"%s\", refusing.",
+@@ -225,3 +241,22 @@
+ 
+         return r;
+ }
++
++int rm_rf_child(int fd, const char *name, RemoveFlags flags) {
++
++        /* Removes one specific child of the specified directory */
++
++        if (fd < 0)
++                return -EBADF;
++
++        if (!filename_is_valid(name))
++                return -EINVAL;
++
++        if ((flags & (REMOVE_ROOT|REMOVE_MISSING_OK)) != 0) /* Doesn't really make sense here, we are not supposed to remove 'fd' anyway */
++                return -EINVAL;
++
++        if (FLAGS_SET(flags, REMOVE_ONLY_DIRECTORIES|REMOVE_SUBVOLUME))
++                return -EINVAL;
++
++        return rm_rf_children_inner(fd, name, -1, flags, NULL);
++}
+--- a/src/basic/rm-rf.h
++++ b/src/basic/rm-rf.h
+@@ -13,7 +13,8 @@
+         REMOVE_MISSING_OK       = 1 << 4, /* If the top-level directory is missing, ignore the ENOENT for it */
+ } RemoveFlags;
+ 
+-int rm_rf_children(int fd, RemoveFlags flags, struct stat *root_dev);
++int rm_rf_children(int fd, RemoveFlags flags, const struct stat *root_dev);
++int rm_rf_child(int fd, const char *name, RemoveFlags flags);
+ int rm_rf(const char *path, RemoveFlags flags);
+ 
+ /* Useful for usage with _cleanup_(), destroys a directory and frees the pointer */