From eeb621aa19f690971caf862290a172a115578ba1 Mon Sep 17 00:00:00 2001 From: Chen Qi Date: Fri, 2 Nov 2018 12:42:42 +0800 Subject: systemd: fix CVE-2018-15687 Backport patch to fix the following CVE. CVE: CVE-2018-15687 Signed-off-by: Chen Qi Signed-off-by: Richard Purdie --- ...sive-let-s-rework-the-recursive-logic-to-.patch | 219 +++++++++++++++++++++ meta/recipes-core/systemd/systemd_239.bb | 1 + 2 files changed, 220 insertions(+) create mode 100644 meta/recipes-core/systemd/systemd/0001-chown-recursive-let-s-rework-the-recursive-logic-to-.patch (limited to 'meta/recipes-core/systemd') diff --git a/meta/recipes-core/systemd/systemd/0001-chown-recursive-let-s-rework-the-recursive-logic-to-.patch b/meta/recipes-core/systemd/systemd/0001-chown-recursive-let-s-rework-the-recursive-logic-to-.patch new file mode 100644 index 0000000000..9d350ebade --- /dev/null +++ b/meta/recipes-core/systemd/systemd/0001-chown-recursive-let-s-rework-the-recursive-logic-to-.patch @@ -0,0 +1,219 @@ +From 2da8ba3f507345d0401ea9d7191fa16ffa560ebc Mon Sep 17 00:00:00 2001 +From: Lennart Poettering +Date: Fri, 19 Oct 2018 11:26:59 +0200 +Subject: [PATCH] chown-recursive: let's rework the recursive logic to use + O_PATH + +That way we can pin a specific inode and analyze it and manipulate it +without it being swapped out beneath our hands. + +Fixes a vulnerability originally found by Jann Horn from Google. + +CVE-2018-15687 +LP: #1796692 +https://bugzilla.redhat.com/show_bug.cgi?id=1639076 + +(cherry picked from commit 5de6cce58b3e8b79239b6e83653459d91af6e57c) + +CVE: CVE-2018-15687 +Upstream-Status: Backport + +Signed-off-by: Chen Qi +--- + src/core/chown-recursive.c | 146 ++++++++++++++++++++++----------------------- + 1 file changed, 70 insertions(+), 76 deletions(-) + +diff --git a/src/core/chown-recursive.c b/src/core/chown-recursive.c +index c479450..27c6448 100644 +--- a/src/core/chown-recursive.c ++++ b/src/core/chown-recursive.c +@@ -1,17 +1,19 @@ + /* SPDX-License-Identifier: LGPL-2.1+ */ + +-#include +-#include + #include ++#include ++#include + +-#include "user-util.h" +-#include "macro.h" +-#include "fd-util.h" +-#include "dirent-util.h" + #include "chown-recursive.h" ++#include "dirent-util.h" ++#include "fd-util.h" ++#include "macro.h" ++#include "stdio-util.h" ++#include "strv.h" ++#include "user-util.h" + +-static int chown_one(int fd, const char *name, const struct stat *st, uid_t uid, gid_t gid) { +- int r; ++static int chown_one(int fd, const struct stat *st, uid_t uid, gid_t gid) { ++ char procfs_path[STRLEN("/proc/self/fd/") + DECIMAL_STR_MAX(int) + 1]; + + assert(fd >= 0); + assert(st); +@@ -20,90 +22,82 @@ static int chown_one(int fd, const char *name, const struct stat *st, uid_t uid, + (!gid_is_valid(gid) || st->st_gid == gid)) + return 0; + +- if (name) +- r = fchownat(fd, name, uid, gid, AT_SYMLINK_NOFOLLOW); +- else +- r = fchown(fd, uid, gid); +- if (r < 0) +- return -errno; ++ /* We change ownership through the /proc/self/fd/%i path, so that we have a stable reference that works with ++ * O_PATH. (Note: fchown() and fchmod() do not work with O_PATH, the kernel refuses that. */ ++ xsprintf(procfs_path, "/proc/self/fd/%i", fd); + +- /* The linux kernel alters the mode in some cases of chown(). Let's undo this. */ +- if (name) { +- if (!S_ISLNK(st->st_mode)) +- r = fchmodat(fd, name, st->st_mode, 0); +- else /* There's currently no AT_SYMLINK_NOFOLLOW for fchmodat() */ +- r = 0; +- } else +- r = fchmod(fd, st->st_mode); +- if (r < 0) ++ if (chown(procfs_path, uid, gid) < 0) + return -errno; + ++ /* The linux kernel alters the mode in some cases of chown(). Let's undo this. We do this only for non-symlinks ++ * however. That's because for symlinks the access mode is ignored anyway and because on some kernels/file ++ * systems trying to change the access mode will succeed but has no effect while on others it actively ++ * fails. */ ++ if (!S_ISLNK(st->st_mode)) ++ if (chmod(procfs_path, st->st_mode & 07777) < 0) ++ return -errno; ++ + return 1; + } + + static int chown_recursive_internal(int fd, const struct stat *st, uid_t uid, gid_t gid) { ++ _cleanup_closedir_ DIR *d = NULL; + bool changed = false; ++ struct dirent *de; + int r; + + assert(fd >= 0); + assert(st); + +- if (S_ISDIR(st->st_mode)) { +- _cleanup_closedir_ DIR *d = NULL; +- struct dirent *de; +- +- d = fdopendir(fd); +- if (!d) { +- r = -errno; +- goto finish; +- } +- fd = -1; +- +- FOREACH_DIRENT_ALL(de, d, r = -errno; goto finish) { +- struct stat fst; +- +- if (dot_or_dot_dot(de->d_name)) +- continue; +- +- if (fstatat(dirfd(d), de->d_name, &fst, AT_SYMLINK_NOFOLLOW) < 0) { +- r = -errno; +- goto finish; +- } +- +- if (S_ISDIR(fst.st_mode)) { +- int subdir_fd; +- +- subdir_fd = openat(dirfd(d), de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); +- if (subdir_fd < 0) { +- r = -errno; +- goto finish; +- } +- +- r = chown_recursive_internal(subdir_fd, &fst, uid, gid); +- if (r < 0) +- goto finish; +- if (r > 0) +- changed = true; +- } else { +- r = chown_one(dirfd(d), de->d_name, &fst, uid, gid); +- if (r < 0) +- goto finish; +- if (r > 0) +- changed = true; +- } ++ d = fdopendir(fd); ++ if (!d) { ++ safe_close(fd); ++ return -errno; ++ } ++ ++ FOREACH_DIRENT_ALL(de, d, return -errno) { ++ _cleanup_close_ int path_fd = -1; ++ struct stat fst; ++ ++ if (dot_or_dot_dot(de->d_name)) ++ continue; ++ ++ /* Let's pin the child inode we want to fix now with an O_PATH fd, so that it cannot be swapped out ++ * while we manipulate it. */ ++ path_fd = openat(dirfd(d), de->d_name, O_PATH|O_CLOEXEC|O_NOFOLLOW); ++ if (path_fd < 0) ++ return -errno; ++ ++ if (fstat(path_fd, &fst) < 0) ++ return -errno; ++ ++ if (S_ISDIR(fst.st_mode)) { ++ int subdir_fd; ++ ++ /* Convert it to a "real" (i.e. non-O_PATH) fd now */ ++ subdir_fd = fd_reopen(path_fd, O_RDONLY|O_CLOEXEC|O_NOATIME); ++ if (subdir_fd < 0) ++ return subdir_fd; ++ ++ r = chown_recursive_internal(subdir_fd, &fst, uid, gid); /* takes possession of subdir_fd even on failure */ ++ if (r < 0) ++ return r; ++ if (r > 0) ++ changed = true; ++ } else { ++ r = chown_one(path_fd, &fst, uid, gid); ++ if (r < 0) ++ return r; ++ if (r > 0) ++ changed = true; + } ++ } + +- r = chown_one(dirfd(d), NULL, st, uid, gid); +- } else +- r = chown_one(fd, NULL, st, uid, gid); ++ r = chown_one(dirfd(d), st, uid, gid); + if (r < 0) +- goto finish; ++ return r; + +- r = r > 0 || changed; +- +-finish: +- safe_close(fd); +- return r; ++ return r > 0 || changed; + } + + int path_chown_recursive(const char *path, uid_t uid, gid_t gid) { +@@ -111,7 +105,7 @@ int path_chown_recursive(const char *path, uid_t uid, gid_t gid) { + struct stat st; + int r; + +- fd = open(path, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); ++ fd = open(path, O_RDONLY|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW|O_NOATIME); + if (fd < 0) + return -errno; + +-- +2.7.4 + diff --git a/meta/recipes-core/systemd/systemd_239.bb b/meta/recipes-core/systemd/systemd_239.bb index 48b6c3aa42..47fff40a4b 100644 --- a/meta/recipes-core/systemd/systemd_239.bb +++ b/meta/recipes-core/systemd/systemd_239.bb @@ -31,6 +31,7 @@ SRC_URI += "file://touchscreen.rules \ file://0022-build-sys-Detect-whether-struct-statx-is-defined-in-.patch \ file://0023-resolvconf-fixes-for-the-compatibility-interface.patch \ file://0001-core-when-deserializing-state-always-use-read_line-L.patch \ + file://0001-chown-recursive-let-s-rework-the-recursive-logic-to-.patch \ " # patches made for musl are only applied on TCLIBC is musl -- cgit 1.2.3-korg