git: 7ed19f5c7780 - main - libpfctl: grow request buffer on ENOSPC

The branch main has been updated by kp:

URL: https://cgit.FreeBSD.org/src/commit/?id=7ed19f5c7780ebe9ec67121f0c5aa19fbc80bf1a

commit 7ed19f5c7780ebe9ec67121f0c5aa19fbc80bf1a
Author:     Kristof Provost <kp@FreeBSD.org>
AuthorDate: 2022-04-14 12:08:53 +0000
Commit:     Kristof Provost <kp@FreeBSD.org>
CommitDate: 2022-04-20 08:51:39 +0000

    libpfctl: grow request buffer on ENOSPC
    
    When we issue a request to pf and expect a serialised nvlist as a reply
    we have to supply a suitable buffer to the kernel.
    The required size for this buffer is difficult to predict, and may be
    (slightly) different from request to request.
    If it's insufficient the kernel will return ENOSPC. Teach libpfctl to
    catch this and send the request again with a larger buffer.
    
    MFC after:      2 weeks
    Sponsored by:   Rubicon Communications, LLC ("Netgate")
    Differential Revision:  https://reviews.freebsd.org/D34908
---
 lib/libpfctl/libpfctl.c | 200 +++++++++++++++---------------------------------
 1 file changed, 61 insertions(+), 139 deletions(-)

diff --git a/lib/libpfctl/libpfctl.c b/lib/libpfctl/libpfctl.c
index f3a22106d51b..89123bd80ad5 100644
--- a/lib/libpfctl/libpfctl.c
+++ b/lib/libpfctl/libpfctl.c
@@ -59,6 +59,49 @@ const char* PFCTL_SYNCOOKIES_MODE_NAMES[] = {
 static int	_pfctl_clear_states(int , const struct pfctl_kill *,
 		    unsigned int *, uint64_t);
 
+static int
+pfctl_do_ioctl(int dev, uint cmd, size_t size, nvlist_t **nvl)
+{
+	struct pfioc_nv nv;
+	void *data;
+	size_t nvlen;
+	int ret;
+
+	data = nvlist_pack(*nvl, &nvlen);
+
+retry:
+	nv.data = malloc(size);
+	memcpy(nv.data, data, nvlen);
+	free(data);
+
+	nv.len = nvlen;
+	nv.size = size;
+
+	ret = ioctl(dev, cmd, &nv);
+	if (ret == -1 && errno == ENOSPC) {
+		size *= 2;
+		free(nv.data);
+		goto retry;
+	}
+
+	nvlist_destroy(*nvl);
+	*nvl = NULL;
+
+	if (ret == 0) {
+		*nvl = nvlist_unpack(nv.data, nv.len, 0);
+		if (*nvl == NULL) {
+			free(nv.data);
+			return (EIO);
+		}
+	} else {
+		ret = errno;
+	}
+
+	free(nv.data);
+
+	return (ret);
+}
+
 static void
 pf_nvuint_8_array(const nvlist_t *nvl, const char *name, size_t maxelems,
     uint8_t *numbers, size_t *nelems)
@@ -159,7 +202,6 @@ _pfctl_get_status_counters(const nvlist_t *nvl,
 struct pfctl_status *
 pfctl_get_status(int dev)
 {
-	struct pfioc_nv	 nv;
 	struct pfctl_status	*status;
 	nvlist_t	*nvl;
 	size_t		 len;
@@ -169,18 +211,9 @@ pfctl_get_status(int dev)
 	if (status == NULL)
 		return (NULL);
 
-	nv.data = malloc(4096);
-	nv.len = nv.size = 4096;
-
-	if (ioctl(dev, DIOCGETSTATUSNV, &nv)) {
-		free(nv.data);
-		free(status);
-		return (NULL);
-	}
+	nvl = nvlist_create(0);
 
-	nvl = nvlist_unpack(nv.data, nv.len, 0);
-	free(nv.data);
-	if (nvl == NULL) {
+	if (pfctl_do_ioctl(dev, DIOCGETSTATUSNV, 4096, &nvl)) {
 		free(status);
 		return (NULL);
 	}
@@ -626,31 +659,16 @@ int
 pfctl_get_eth_rulesets_info(int dev, struct pfctl_eth_rulesets_info *ri,
     const char *path)
 {
-	uint8_t buf[1024];
-	struct pfioc_nv nv;
 	nvlist_t *nvl;
-	void *packed;
-	size_t len;
+	int ret;
 
 	bzero(ri, sizeof(*ri));
 
 	nvl = nvlist_create(0);
 	nvlist_add_string(nvl, "path", path);
-	packed = nvlist_pack(nvl, &len);
-	memcpy(buf, packed, len);
-	free(packed);
-	nvlist_destroy(nvl);
-
-	nv.data = buf;
-	nv.len = len;
-	nv.size = sizeof(buf);
 
-	if (ioctl(dev, DIOCGETETHRULESETS, &nv) != 0)
-		return (errno);
-
-	nvl = nvlist_unpack(buf, nv.len, 0);
-	if (nvl == NULL)
-		return (EIO);
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETETHRULESETS, 256, &nvl)) != 0)
+		return (ret);
 
 	ri->nr = nvlist_get_number(nvl, "nr");
 
@@ -662,32 +680,17 @@ int
 pfctl_get_eth_ruleset(int dev, const char *path, int nr,
     struct pfctl_eth_ruleset_info *ri)
 {
-	uint8_t buf[1024];
-	struct pfioc_nv nv;
 	nvlist_t *nvl;
-	void *packed;
-	size_t len;
+	int ret;
 
 	bzero(ri, sizeof(*ri));
 
 	nvl = nvlist_create(0);
 	nvlist_add_string(nvl, "path", path);
 	nvlist_add_number(nvl, "nr", nr);
-	packed = nvlist_pack(nvl, &len);
-	memcpy(buf, packed, len);
-	free(packed);
-	nvlist_destroy(nvl);
-
-	nv.data = buf;
-	nv.len = len;
-	nv.size = sizeof(buf);
 
-	if (ioctl(dev, DIOCGETETHRULESET, &nv) != 0)
-		return (errno);
-
-	nvl = nvlist_unpack(buf, nv.len, 0);
-	if (nvl == NULL)
-		return (EIO);
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETETHRULESET, 1024, &nvl)) != 0)
+		return (ret);
 
 	ri->nr = nvlist_get_number(nvl, "nr");
 	strlcpy(ri->path, nvlist_get_string(nvl, "path"), MAXPATHLEN);
@@ -701,31 +704,16 @@ int
 pfctl_get_eth_rules_info(int dev, struct pfctl_eth_rules_info *rules,
     const char *path)
 {
-	uint8_t buf[1024];
-	struct pfioc_nv nv;
 	nvlist_t *nvl;
-	void *packed;
-	size_t len;
+	int ret;
 
 	bzero(rules, sizeof(*rules));
 
 	nvl = nvlist_create(0);
 	nvlist_add_string(nvl, "anchor", path);
-	packed = nvlist_pack(nvl, &len);
-	memcpy(buf, packed, len);
-	free(packed);
-	nvlist_destroy(nvl);
 
-	nv.data = buf;
-	nv.len = len;
-	nv.size = sizeof(buf);
-
-	if (ioctl(dev, DIOCGETETHRULES, &nv) != 0)
-		return (errno);
-
-	nvl = nvlist_unpack(buf, nv.len, 0);
-	if (nvl == NULL)
-		return (EIO);
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETETHRULES, 1024, &nvl)) != 0)
+		return (ret);
 
 	rules->nr = nvlist_get_number(nvl, "nr");
 	rules->ticket = nvlist_get_number(nvl, "ticket");
@@ -739,11 +727,8 @@ pfctl_get_eth_rule(int dev, uint32_t nr, uint32_t ticket,
     const char *path, struct pfctl_eth_rule *rule, bool clear,
     char *anchor_call)
 {
-	uint8_t buf[2048];
-	struct pfioc_nv nv;
 	nvlist_t *nvl;
-	void *data;
-	size_t len;
+	int ret;
 
 	nvl = nvlist_create(0);
 
@@ -752,22 +737,8 @@ pfctl_get_eth_rule(int dev, uint32_t nr, uint32_t ticket,
 	nvlist_add_number(nvl, "nr", nr);
 	nvlist_add_bool(nvl, "clear", clear);
 
-	data = nvlist_pack(nvl, &len);
-	nv.data = buf;
-	memcpy(buf, data, len);
-	free(data);
-	nv.len = len;
-	nv.size = sizeof(buf);
-	if (ioctl(dev, DIOCGETETHRULE, &nv)) {
-		nvlist_destroy(nvl);
-		return (errno);
-	}
-	nvlist_destroy(nvl);
-
-	nvl = nvlist_unpack(buf, nv.len, 0);
-	if (nvl == NULL) {
-		return (EIO);
-	}
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETETHRULE, 2048, &nvl)) != 0)
+		return (ret);
 
 	pfctl_nveth_rule_to_eth_rule(nvl, rule);
 
@@ -1004,9 +975,7 @@ int	pfctl_get_clear_rule(int dev, uint32_t nr, uint32_t ticket,
 	    const char *anchor, uint32_t ruleset, struct pfctl_rule *rule,
 	    char *anchor_call, bool clear)
 {
-	struct pfioc_nv nv;
 	nvlist_t *nvl;
-	void *nvlpacked;
 	int ret;
 
 	nvl = nvlist_create(0);
@@ -1021,30 +990,8 @@ int	pfctl_get_clear_rule(int dev, uint32_t nr, uint32_t ticket,
 	if (clear)
 		nvlist_add_bool(nvl, "clear_counter", true);
 
-	nvlpacked = nvlist_pack(nvl, &nv.len);
-	if (nvlpacked == NULL) {
-		nvlist_destroy(nvl);
-		return (ENOMEM);
-	}
-	nv.data = malloc(8182);
-	nv.size = 8192;
-	assert(nv.len <= nv.size);
-	memcpy(nv.data, nvlpacked, nv.len);
-	nvlist_destroy(nvl);
-	nvl = NULL;
-	free(nvlpacked);
-
-	ret = ioctl(dev, DIOCGETRULENV, &nv);
-	if (ret != 0) {
-		free(nv.data);
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETRULENV, 8192, &nvl)) != 0)
 		return (ret);
-	}
-
-	nvl = nvlist_unpack(nv.data, nv.len, 0);
-	if (nvl == NULL) {
-		free(nv.data);
-		return (EIO);
-	}
 
 	pf_nvrule_to_rule(nvlist_get_nvlist(nvl, "rule"), rule);
 
@@ -1052,7 +999,6 @@ int	pfctl_get_clear_rule(int dev, uint32_t nr, uint32_t ticket,
 		strlcpy(anchor_call, nvlist_get_string(nvl, "anchor_call"),
 		    MAXPATHLEN);
 
-	free(nv.data);
 	nvlist_destroy(nvl);
 
 	return (0);
@@ -1238,22 +1184,8 @@ _pfctl_clear_states(int dev, const struct pfctl_kill *kill,
 	nvlist_add_string(nvl, "label", kill->label);
 	nvlist_add_bool(nvl, "kill_match", kill->kill_match);
 
-	nv.data = nvlist_pack(nvl, &nv.len);
-	nv.size = nv.len;
-	nvlist_destroy(nvl);
-	nvl = NULL;
-
-	ret = ioctl(dev, ioctlval, &nv);
-	if (ret != 0) {
-		free(nv.data);
+	if ((ret = pfctl_do_ioctl(dev, ioctlval, 1024, &nvl)) != 0)
 		return (ret);
-	}
-
-	nvl = nvlist_unpack(nv.data, nv.len, 0);
-	if (nvl == NULL) {
-		free(nv.data);
-		return (EIO);
-	}
 
 	if (killed)
 		*killed = nvlist_get_number(nvl, "killed");
@@ -1415,7 +1347,6 @@ pfctl_set_syncookies(int dev, const struct pfctl_syncookies *s)
 int
 pfctl_get_syncookies(int dev, struct pfctl_syncookies *s)
 {
-	struct pfioc_nv	 nv;
 	nvlist_t	*nvl;
 	int		 ret;
 	uint		 state_limit;
@@ -1427,19 +1358,10 @@ pfctl_get_syncookies(int dev, struct pfctl_syncookies *s)
 
 	bzero(s, sizeof(*s));
 
-	nv.data = malloc(256);
-	nv.len = nv.size = 256;
+	nvl = nvlist_create(0);
 
-	if (ioctl(dev, DIOCGETSYNCOOKIES, &nv)) {
-		free(nv.data);
+	if ((ret = pfctl_do_ioctl(dev, DIOCGETSYNCOOKIES, 256, &nvl)) != 0)
 		return (errno);
-	}
-
-	nvl = nvlist_unpack(nv.data, nv.len, 0);
-	free(nv.data);
-	if (nvl == NULL) {
-		return (EIO);
-	}
 
 	enabled = nvlist_get_bool(nvl, "enabled");
 	adaptive = nvlist_get_bool(nvl, "adaptive");