From bbe9ac11d8d4a8511214605509a593fb9f04ffaa Mon Sep 17 00:00:00 2001

From: Lennart Poettering <lennart@poettering.net>

Date: Fri, 19 Oct 2018 11:28:40 +0200

Subject: [PATCH] chown-recursive: also drop ACLs when recursively chown()ing

Let's better be safe than sorry and also drop ACLs.

(cherry-picked from commit f89bc84f3242449cbc308892c87573b131f121df)

Related: #1643368

---

 src/core/chown-recursive.c | 16 ++++++++++++----

 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/core/chown-recursive.c b/src/core/chown-recursive.c

index 27c64489b5..447b771267 100644

--- a/src/core/chown-recursive.c

+++ b/src/core/chown-recursive.c

@@ -3,6 +3,7 @@

 #include <fcntl.h>

 #include <sys/stat.h>

 #include <sys/types.h>

+#include <sys/xattr.h>

 #include "chown-recursive.h"

 #include "dirent-util.h"

@@ -14,6 +15,7 @@

 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];

+        const char *n;

         assert(fd >= 0);

         assert(st);

@@ -26,13 +28,19 @@ static int chown_one(int fd, const struct stat *st, uid_t uid, gid_t gid) {

          * O_PATH. (Note: fchown() and fchmod() do not work with O_PATH, the kernel refuses that. */

         xsprintf(procfs_path, "/proc/self/fd/%i", fd);

+        /* Drop any ACL if there is one */

+        FOREACH_STRING(n, "system.posix_acl_access", "system.posix_acl_default")

+                if (removexattr(procfs_path, n) < 0)

+                        if (!IN_SET(errno, ENODATA, EOPNOTSUPP, ENOSYS, ENOTTY))

+                                return -errno;

+

         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. */

+        /* The linux kernel alters the mode in some cases of chown(), as well when we change ACLs. 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;