When parsing an nftnl_rule with a standard verdict, nft_rule_to_iptables_command_state() initialized cs->target but didn't care about cs->target->t. When later comparing that rule to another, compare_targets() crashed due to unconditional access to t's fields.
Signed-off-by: Phil Sutter <[email protected]> --- Changes since v1: - Fix for double free caused by not setting cs->target->t to NULL after freeing it. --- iptables/nft-shared.c | 23 +++++++++++++++---- .../testcases/iptables/0005-delete-rules_0 | 7 ++++++ iptables/xtables.c | 4 +++- 3 files changed, 29 insertions(+), 5 deletions(-) create mode 100755 iptables/tests/shell/testcases/iptables/0005-delete-rules_0 diff --git a/iptables/nft-shared.c b/iptables/nft-shared.c index ca4e593656562..2d4b8d557eb73 100644 --- a/iptables/nft-shared.c +++ b/iptables/nft-shared.c @@ -660,19 +660,34 @@ void nft_rule_to_iptables_command_state(const struct nftnl_rule *r, match->m = m; } - if (cs->target != NULL) + if (cs->target != NULL) { cs->jumpto = cs->target->name; - else if (cs->jumpto != NULL) + } else if (cs->jumpto != NULL) { + struct xt_entry_target *t; + uint32_t size; + cs->target = xtables_find_target(cs->jumpto, XTF_TRY_LOAD); - else + if (!cs->target) + return; + + size = XT_ALIGN(sizeof(struct xt_entry_target)) + cs->target->size; + t = xtables_calloc(1, size); + t->u.target_size = size; + t->u.user.revision = cs->target->revision; + strcpy(t->u.user.name, cs->jumpto); + cs->target->t = t; + } else { cs->jumpto = ""; + } } void nft_clear_iptables_command_state(struct iptables_command_state *cs) { xtables_rule_matches_free(&cs->matches); - if (cs->target) + if (cs->target) { free(cs->target->t); + cs->target->t = NULL; + } } void print_header(unsigned int format, const char *chain, const char *pol, diff --git a/iptables/tests/shell/testcases/iptables/0005-delete-rules_0 b/iptables/tests/shell/testcases/iptables/0005-delete-rules_0 new file mode 100755 index 0000000000000..9312fd53c3437 --- /dev/null +++ b/iptables/tests/shell/testcases/iptables/0005-delete-rules_0 @@ -0,0 +1,7 @@ +#!/bin/bash + +# test for crash when comparing rules with standard target + +$XT_MULTI iptables -A FORWARD -i eth23 -o eth42 -j DROP +$XT_MULTI iptables -D FORWARD -i eth23 -o eth42 -j REJECT +[[ $? -eq 1 ]] || exit 1 diff --git a/iptables/xtables.c b/iptables/xtables.c index d0167e6396975..eaa9fedeb03bb 100644 --- a/iptables/xtables.c +++ b/iptables/xtables.c @@ -1185,8 +1185,10 @@ int do_commandx(struct nft_handle *h, int argc, char *argv[], char **table, *table = p.table; xtables_rule_matches_free(&cs.matches); - if (cs.target) + if (cs.target) { free(cs.target->t); + cs.target->t = NULL; + } if (h->family == AF_INET) { free(args.s.addr.v4); -- 2.20.1
