https://github.com/systemd/systemd/pull/25957 https://github.com/systemd/systemd/pull/25959 https://github.com/systemd/systemd/commit/9f804ab04d566ff745849e1c4ced680a0447cf76 https://github.com/systemd/systemd/commit/34680637e838415204850f77c93ca6ca219abaf1 From 9f804ab04d566ff745849e1c4ced680a0447cf76 Mon Sep 17 00:00:00 2001 From: Sam James Date: Fri, 6 Jan 2023 10:58:32 +0000 Subject: [PATCH] tmpfiles: avoid null free() for acl attributes When built with ACL support, we might be processing a tmpfiles entry where there's no cause for us to call parse_acls_from_arg, then we get to the end of parse_line without having ever populated i.{acl_access, acl_default}. Then we pass a null pointer into acl_free(). From UBSAN w/ GCC 13.0.0_pre20230101: ``` $ systemd-tmpfiles --clean /var/tmp/portage/sys-apps/acl-2.3.1-r1/work/acl-2.3.1/libacl/acl_free.c:44:14: runtime error: applying non-zero offset 18446744073709551608 to null pointer #0 0x7f65d868b482 in acl_free /var/tmp/portage/sys-apps/acl-2.3.1-r1/work/acl-2.3.1/libacl/acl_free.c:44 #1 0x55fe7e592249 in item_free_contents ../systemd-9999/src/tmpfiles/tmpfiles.c:2855 #2 0x55fe7e5a347a in parse_line ../systemd-9999/src/tmpfiles/tmpfiles.c:3158 #3 0x55fe7e5a347a in read_config_file ../systemd-9999/src/tmpfiles/tmpfiles.c:3897 #4 0x55fe7e590c61 in read_config_files ../systemd-9999/src/tmpfiles/tmpfiles.c:3985 #5 0x55fe7e590c61 in run ../systemd-9999/src/tmpfiles/tmpfiles.c:4157 #6 0x55fe7e590c61 in main ../systemd-9999/src/tmpfiles/tmpfiles.c:4218 #7 0x7f65d7ebe289 (/usr/lib64/libc.so.6+0x23289) #8 0x7f65d7ebe344 in __libc_start_main (/usr/lib64/libc.so.6+0x23344) #9 0x55fe7e591900 in _start (/usr/bin/systemd-tmpfiles+0x11900) ``` --- a/src/tmpfiles/tmpfiles.c +++ b/src/tmpfiles/tmpfiles.c @@ -2852,8 +2852,11 @@ static void item_free_contents(Item *i) { strv_free(i->xattrs); #if HAVE_ACL - acl_free(i->acl_access); - acl_free(i->acl_default); + if (i->acl_access) + acl_free(i->acl_access); + + if (i->acl_default) + acl_free(i->acl_default); #endif } From 34680637e838415204850f77c93ca6ca219abaf1 Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Fri, 6 Jan 2023 12:30:36 +0100 Subject: [PATCH] nspawn: guard acl_free() with a NULL check Inspired by #25957 there's one other place where we don't guard acl_free() calls with a NULL check. Fix that. --- a/src/nspawn/nspawn-patch-uid.c +++ b/src/nspawn/nspawn-patch-uid.c @@ -181,7 +181,9 @@ static int patch_acls(int fd, const char *name, const struct stat *st, uid_t shi if (S_ISDIR(st->st_mode)) { acl_free(acl); - acl_free(shifted); + + if (shifted) + acl_free(shifted); acl = shifted = NULL;