From 85e06ba8753e767d9f28550bf9f6b0d2e971b296 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) ``` (cherry picked from commit 9f804ab04d566ff745849e1c4ced680a0447cf76) (cherry picked from commit a11a949c43def70ec5d3f57f561884c3f652603e) (cherry picked from commit 455193605d22a171c0f9b599a105be9ac18f433f) (cherry picked from commit 0e711b7c06fc8b1290adcd38b4bb8faaa49ab764) --- src/tmpfiles/tmpfiles.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/src/tmpfiles/tmpfiles.c b/src/tmpfiles/tmpfiles.c index 1bfb1cbe16..461dfe5a5f 100644 --- a/src/tmpfiles/tmpfiles.c +++ b/src/tmpfiles/tmpfiles.c @@ -2683,8 +2683,11 @@ 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 } -- 2.27.0