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Correctly truncate the rule in case when it has several action opcodes.

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It is possible, that opcode at the ACTION_PTR() location is not real
action, but action modificator like "log", "tag" etc. In this case we
need to check for each opcode in the loop to find O_EXTERNAL_ACTION.

Obtained from:	Yandex LLC
MFC after:	1 week
Sponsored by:	Yandex LLC
This commit is contained in:
Andrey V. Elsukov 2019-07-12 09:48:42 +00:00
parent ccbb355988
commit 4ee2f4c180
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=349940
1 changed files with 30 additions and 14 deletions
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44
sys/netpfil/ipfw/ip_fw_eaction.c
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@ -377,35 +377,51 @@ ipfw_reset_eaction(struct ip_fw_chain *ch, struct ip_fw *rule,
uint16_t eaction_id, uint16_t default_id, uint16_t instance_id)
{
ipfw_insn *cmd, *icmd;
int l, cmdlen;
IPFW_UH_WLOCK_ASSERT(ch);
IPFW_WLOCK_ASSERT(ch);
cmd = ACTION_PTR(rule);
l = rule->cmd_len - rule->act_ofs;
while (l > 0) {
cmdlen = F_LEN(cmd);
l -= cmdlen;
if (cmd->opcode == O_EXTERNAL_ACTION)
break;
cmd += cmdlen;
}
/*
* Return if there is not O_EXTERNAL_ACTION or its id is
* different.
*/
if (cmd->opcode != O_EXTERNAL_ACTION ||
cmd->arg1 != eaction_id)
return (0);
if (instance_id != 0 && rule->act_ofs < rule->cmd_len - 1) {
/*
* If instance_id is specified, we need to truncate the
* rule length. Check if there is O_EXTERNAL_INSTANCE opcode.
*/
if (instance_id != 0 && l > 0) {
MPASS(cmdlen == 1);
icmd = cmd + 1;
if (icmd->opcode != O_EXTERNAL_INSTANCE ||
icmd->arg1 != instance_id)
return (0);
/* FALLTHROUGH */
/*
* Since named_object related to this instance will be
* destroyed, truncate the chain of opcodes to remove
* the rest of cmd chain just after O_EXTERNAL_ACTION
* opcode.
*/
EACTION_DEBUG("truncate rule %d: len %u -> %u",
rule->rulenum, rule->cmd_len, rule->cmd_len - l);
rule->cmd_len -= l;
MPASS(((uint32_t *)icmd -
(uint32_t *)rule->cmd) == rule->cmd_len);
}
cmd->arg1 = default_id; /* Set to default id */
/*
* Since named_object related to this instance will be
* also destroyed, truncate the chain of opcodes to
* remove the rest of cmd chain just after O_EXTERNAL_ACTION
* opcode.
*/
if (rule->act_ofs < rule->cmd_len - 1) {
EACTION_DEBUG("truncate rule %d: len %u -> %u",
rule->rulenum, rule->cmd_len, rule->act_ofs + 1);
rule->cmd_len = rule->act_ofs + 1;
}
/*
* Return 1 when reset successfully happened.
*/