ASAN reports an issue when collapsing commands that represent an element through a variable: include/list.h:60:13: runtime error: member access within null pointer of type 'struct list_head' AddressSanitizer:DEADLYSIGNAL ================================================================= ==11398==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7ffb77cf09c2 bp 0x7ffc818267c0 sp 0x7ffc818267a0 T0) ==11398==The signal is caused by a WRITE memory access. ==11398==Hint: address points to the zero page. #0 0x7ffb77cf09c2 in __list_add include/list.h:60 #1 0x7ffb77cf0ad9 in list_add_tail include/list.h:87 #2 0x7ffb77cf0e72 in list_move_tail include/list.h:169 #3 0x7ffb77cf86ad in nft_cmd_collapse src/cmd.c:478 #4 0x7ffb77da9f16 in nft_evaluate src/libnftables.c:531 #5 0x7ffb77dac471 in __nft_run_cmd_from_filename src/libnftables.c:720 #6 0x7ffb77dad703 in nft_run_cmd_from_filename src/libnftables.c:807 Skip such commands to address this issue. Closes: https://bugzilla.netfilter.org/show_bug.cgi?id=1754 Fixes: 498a5f0c219d ("rule: collapse set element commands") Signed-off-by: Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx> --- src/cmd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/src/cmd.c b/src/cmd.c index d6b1d844ed8d..37d93abc2cd4 100644 --- a/src/cmd.c +++ b/src/cmd.c @@ -455,6 +455,9 @@ bool nft_cmd_collapse(struct list_head *cmds) continue; } + if (cmd->expr->etype == EXPR_VARIABLE) + continue; + if (!elems) { elems = cmd; continue; -- 2.30.2