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From: David Gibson <david@gibson.dropbear.id.au>
To: passt-dev@passt.top
Subject: [PATCH v2 17/32] Consolidate validation of pasta namespace options
Date: Thu, 08 Sep 2022 16:16:06 +1000	[thread overview]
Message-ID: <20220908061621.2430844-18-david@gibson.dropbear.id.au> (raw)
In-Reply-To: <20220908061621.2430844-1-david@gibson.dropbear.id.au>

[-- Attachment #1: Type: text/plain, Size: 5583 bytes --]

There are a number of different ways to specify namespaces for pasta to
use.  Some combinations are valid and some are not.  Currently validation
for these is spread across several places: conf_ns_pid() validates PID
options specifically.  Near its callsite in conf() several other checks
are made. Some additional checks are made in conf_ns_open() and finally
theres a check just before the call to pasta_start_ns().

This is quite hard to follow.  Make it easier by putting all the validation
logic together in a new conf_pasta_ns() function, which subsumes
conf_ns_pid().  This reveals that some of the checks were redundant with
each other, so remove those.

For good measure, rename conf_netns() to conf_netns_opt() to make it
clearer its handling just the --netns option specifically, not overall
configuration of the netns.

Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au>
---
 conf.c | 83 +++++++++++++++++++++++++++++-----------------------------
 1 file changed, 42 insertions(+), 41 deletions(-)

diff --git a/conf.c b/conf.c
index 08a2106..5018794 100644
--- a/conf.c
+++ b/conf.c
@@ -491,13 +491,13 @@ out:
 }
 
 /**
- * conf_netns() - Parse --netns option
+ * conf_netns_opt() - Parse --netns option
  * @netns:	buffer of size PATH_MAX, updated with netns path
  * @arg:	--netns argument
  *
  * Return: 0 on success, negative error code otherwise
  */
-static int conf_netns(char *netns, const char *arg)
+static int conf_netns_opt(char *netns, const char *arg)
 {
 	int ret;
 
@@ -518,40 +518,59 @@ static int conf_netns(char *netns, const char *arg)
 }
 
 /**
- * conf_ns_pid() - Parse non-option argument as a PID
+ * conf_pasta_ns() - Validate all pasta namespace options
+ * @netns_only:	Don't use userns, may be updated
  * @userns:	buffer of size PATH_MAX, initially contains --userns
  *		argument (may be empty), updated with userns path
  * @netns:	buffer of size PATH_MAX, initial contains --netns
  *		argument (may be empty), updated with netns path
- * @arg:	PID of network namespace
+ * @optind:	Index of first non-option argument
+ * @argc:	Number of arguments
+ * @argv:	Command line arguments
  *
  * Return: 0 on success, negative error code otherwise
  */
-static int conf_ns_pid(char *userns, char *netns, const char *arg)
+static int conf_pasta_ns(int *netns_only, char *userns, char *netns,
+			 int optind, int argc, char *argv[])
 {
-	char *endptr;
-	long pidval;
+	if (*netns_only && *userns) {
+		err("Both --userns and --netns-only given");
+		return -EINVAL;
+	}
 
-	if (*netns) {
-		err("Both --netns and PID given");
+	if (*netns && optind != argc) {
+		err("Both --netns and PID or command given");
 		return -EINVAL;
 	}
 
-	pidval = strtol(arg, &endptr, 10);
-	if (!*endptr) {
-		/* Looks like a pid */
-		if (pidval < 0 || pidval > INT_MAX) {
-			err("Invalid PID %s", arg);
-			return -EINVAL;
+	if (optind + 1 == argc) {
+		char *endptr;
+		long pidval;
+
+		pidval = strtol(argv[optind], &endptr, 10);
+		if (!*endptr) {
+			/* Looks like a pid */
+			if (pidval < 0 || pidval > INT_MAX) {
+				err("Invalid PID %s", argv[optind]);
+				return -EINVAL;
+			}
+
+			snprintf(netns, PATH_MAX, "/proc/%ld/ns/net", pidval);
+			if (!*userns)
+				snprintf(userns, PATH_MAX, "/proc/%ld/ns/user",
+					 pidval);
 		}
+	}
 
-		snprintf(netns, PATH_MAX, "/proc/%ld/ns/net", pidval);
-		if (!*userns)
-			snprintf(userns, PATH_MAX, "/proc/%ld/ns/user", pidval);
-		return 0;
+	if (*userns && !*netns) {
+		err("--userns requires --netns or PID");
+		return -EINVAL;
 	}
 
-	/* Not a PID, later code will treat as a command */
+	/* Attaching to a netns/PID, with no userns given */
+	if (*netns && !*userns)
+		*netns_only = 1;
+
 	return 0;
 }
 
@@ -585,11 +604,6 @@ static int conf_ns_open(struct ctx *c, const char *userns, const char *netns)
 {
 	int ufd = -1, nfd = -1;
 
-	if (c->netns_only && *userns) {
-		err("Both --userns and --netns-only given");
-		return -EINVAL;
-	}
-
 	nfd = open(netns, O_RDONLY | O_CLOEXEC);
 	if (nfd < 0) {
 		err("Couldn't open network namespace %s", netns);
@@ -607,7 +621,6 @@ static int conf_ns_open(struct ctx *c, const char *userns, const char *netns)
 
 	c->pasta_netns_fd = nfd;
 	c->pasta_userns_fd = ufd;
-	c->netns_only = !*userns;
 
 	NS_CALL(conf_ns_check, c);
 
@@ -1194,7 +1207,7 @@ void conf(struct ctx *c, int argc, char **argv)
 				usage(argv[0]);
 			}
 
-			ret = conf_netns(netns, optarg);
+			ret = conf_netns_opt(netns, optarg);
 			if (ret < 0)
 				usage(argv[0]);
 			break;
@@ -1573,17 +1586,9 @@ void conf(struct ctx *c, int argc, char **argv)
 	drop_root(uid, gid);
 
 	if (c->mode == MODE_PASTA) {
-		if (*netns && optind != argc) {
-			err("Both --netns and PID or command given");
-			usage(argv[0]);
-		} else if (optind + 1 == argc) {
-			ret = conf_ns_pid(userns, netns, argv[optind]);
-			if (ret < 0)
-				usage(argv[0]);
-		} else if (*userns && !*netns && optind == argc) {
-			err("--userns requires --netns or PID");
+		if (conf_pasta_ns(&c->netns_only, userns, netns,
+				  optind, argc, argv) < 0)
 			usage(argv[0]);
-		}
 	} else if (optind != argc) {
 		usage(argv[0]);
 	}
@@ -1597,10 +1602,6 @@ void conf(struct ctx *c, int argc, char **argv)
 			if (ret < 0)
 				usage(argv[0]);
 		} else {
-			if (*userns) {
-				err("Both --userns and command given");
-				usage(argv[0]);
-			}
 			pasta_start_ns(c, argc - optind, argv + optind);
 		}
 	}
-- 
@@ -491,13 +491,13 @@ out:
 }
 
 /**
- * conf_netns() - Parse --netns option
+ * conf_netns_opt() - Parse --netns option
  * @netns:	buffer of size PATH_MAX, updated with netns path
  * @arg:	--netns argument
  *
  * Return: 0 on success, negative error code otherwise
  */
-static int conf_netns(char *netns, const char *arg)
+static int conf_netns_opt(char *netns, const char *arg)
 {
 	int ret;
 
@@ -518,40 +518,59 @@ static int conf_netns(char *netns, const char *arg)
 }
 
 /**
- * conf_ns_pid() - Parse non-option argument as a PID
+ * conf_pasta_ns() - Validate all pasta namespace options
+ * @netns_only:	Don't use userns, may be updated
  * @userns:	buffer of size PATH_MAX, initially contains --userns
  *		argument (may be empty), updated with userns path
  * @netns:	buffer of size PATH_MAX, initial contains --netns
  *		argument (may be empty), updated with netns path
- * @arg:	PID of network namespace
+ * @optind:	Index of first non-option argument
+ * @argc:	Number of arguments
+ * @argv:	Command line arguments
  *
  * Return: 0 on success, negative error code otherwise
  */
-static int conf_ns_pid(char *userns, char *netns, const char *arg)
+static int conf_pasta_ns(int *netns_only, char *userns, char *netns,
+			 int optind, int argc, char *argv[])
 {
-	char *endptr;
-	long pidval;
+	if (*netns_only && *userns) {
+		err("Both --userns and --netns-only given");
+		return -EINVAL;
+	}
 
-	if (*netns) {
-		err("Both --netns and PID given");
+	if (*netns && optind != argc) {
+		err("Both --netns and PID or command given");
 		return -EINVAL;
 	}
 
-	pidval = strtol(arg, &endptr, 10);
-	if (!*endptr) {
-		/* Looks like a pid */
-		if (pidval < 0 || pidval > INT_MAX) {
-			err("Invalid PID %s", arg);
-			return -EINVAL;
+	if (optind + 1 == argc) {
+		char *endptr;
+		long pidval;
+
+		pidval = strtol(argv[optind], &endptr, 10);
+		if (!*endptr) {
+			/* Looks like a pid */
+			if (pidval < 0 || pidval > INT_MAX) {
+				err("Invalid PID %s", argv[optind]);
+				return -EINVAL;
+			}
+
+			snprintf(netns, PATH_MAX, "/proc/%ld/ns/net", pidval);
+			if (!*userns)
+				snprintf(userns, PATH_MAX, "/proc/%ld/ns/user",
+					 pidval);
 		}
+	}
 
-		snprintf(netns, PATH_MAX, "/proc/%ld/ns/net", pidval);
-		if (!*userns)
-			snprintf(userns, PATH_MAX, "/proc/%ld/ns/user", pidval);
-		return 0;
+	if (*userns && !*netns) {
+		err("--userns requires --netns or PID");
+		return -EINVAL;
 	}
 
-	/* Not a PID, later code will treat as a command */
+	/* Attaching to a netns/PID, with no userns given */
+	if (*netns && !*userns)
+		*netns_only = 1;
+
 	return 0;
 }
 
@@ -585,11 +604,6 @@ static int conf_ns_open(struct ctx *c, const char *userns, const char *netns)
 {
 	int ufd = -1, nfd = -1;
 
-	if (c->netns_only && *userns) {
-		err("Both --userns and --netns-only given");
-		return -EINVAL;
-	}
-
 	nfd = open(netns, O_RDONLY | O_CLOEXEC);
 	if (nfd < 0) {
 		err("Couldn't open network namespace %s", netns);
@@ -607,7 +621,6 @@ static int conf_ns_open(struct ctx *c, const char *userns, const char *netns)
 
 	c->pasta_netns_fd = nfd;
 	c->pasta_userns_fd = ufd;
-	c->netns_only = !*userns;
 
 	NS_CALL(conf_ns_check, c);
 
@@ -1194,7 +1207,7 @@ void conf(struct ctx *c, int argc, char **argv)
 				usage(argv[0]);
 			}
 
-			ret = conf_netns(netns, optarg);
+			ret = conf_netns_opt(netns, optarg);
 			if (ret < 0)
 				usage(argv[0]);
 			break;
@@ -1573,17 +1586,9 @@ void conf(struct ctx *c, int argc, char **argv)
 	drop_root(uid, gid);
 
 	if (c->mode == MODE_PASTA) {
-		if (*netns && optind != argc) {
-			err("Both --netns and PID or command given");
-			usage(argv[0]);
-		} else if (optind + 1 == argc) {
-			ret = conf_ns_pid(userns, netns, argv[optind]);
-			if (ret < 0)
-				usage(argv[0]);
-		} else if (*userns && !*netns && optind == argc) {
-			err("--userns requires --netns or PID");
+		if (conf_pasta_ns(&c->netns_only, userns, netns,
+				  optind, argc, argv) < 0)
 			usage(argv[0]);
-		}
 	} else if (optind != argc) {
 		usage(argv[0]);
 	}
@@ -1597,10 +1602,6 @@ void conf(struct ctx *c, int argc, char **argv)
 			if (ret < 0)
 				usage(argv[0]);
 		} else {
-			if (*userns) {
-				err("Both --userns and command given");
-				usage(argv[0]);
-			}
 			pasta_start_ns(c, argc - optind, argv + optind);
 		}
 	}
-- 
2.37.3


  parent reply	other threads:[~2022-09-08  6:16 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-08  6:15 [PATCH v2 00/32] Improve handling of test temporary files David Gibson
2022-09-08  6:15 ` [PATCH v2 01/32] test: Correctly match "background" with "wait" commands David Gibson
2022-09-08  6:15 ` [PATCH v2 02/32] test: Context execution helpers David Gibson
2022-09-08  6:15 ` [PATCH v2 03/32] test: Allow a tmux pane to watch commands executed in contexts David Gibson
2022-09-08  6:15 ` [PATCH v2 04/32] test: Integration of old-style pane execution and new context execution David Gibson
2022-09-08  6:15 ` [PATCH v2 05/32] test: Issue host commands via context for most tests David Gibson
2022-09-08  6:15 ` [PATCH v2 06/32] test: Use new-style contexts for passt pane in the pasta and passt tests David Gibson
2022-09-08  6:15 ` [PATCH v2 07/32] test: Add nsholder utility David Gibson
2022-09-08  6:15 ` [PATCH v2 08/32] test: Extend context system to run commands in namespace for pasta tests David Gibson
2022-09-08  6:15 ` [PATCH v2 09/32] test: Use context system for guest commands David Gibson
2022-09-08  6:15 ` [PATCH v2 10/32] test: Use context system for two_guests tests David Gibson
2022-09-08  6:16 ` [PATCH v2 11/32] test: Use new-style command issue for passt_in_ns tests David Gibson
2022-09-08  6:16 ` [PATCH v2 12/32] Don't store UID & GID persistently in the context structure David Gibson
2022-09-08  6:16 ` [PATCH v2 13/32] Split checking for root from dropping root privilege David Gibson
2022-09-08  6:16 ` [PATCH v2 14/32] Consolidate determination of UID/GID to run as David Gibson
2022-09-08  6:16 ` [PATCH v2 15/32] Safer handling if we can't open /proc/self/uid_map David Gibson
2022-09-08  6:16 ` [PATCH v2 16/32] Move self-isolation code into a separate file David Gibson
2022-09-08  6:16 ` David Gibson [this message]
2022-09-08  6:16 ` [PATCH v2 18/32] Clean up and rename conf_ns_open() David Gibson
2022-09-08  6:16 ` [PATCH v2 19/32] Correctly handle --netns-only in pasta_start_ns() David Gibson
2022-09-08  6:16 ` [PATCH v2 20/32] Handle userns isolation and dropping root at the same time David Gibson
2022-09-08  6:16 ` [PATCH v2 21/32] Allow --userns when pasta spawns a command David Gibson
2022-09-08  6:16 ` [PATCH v2 22/32] test: Group tests by context then protocol, rather than the reverse David Gibson
2022-09-08  6:16 ` [PATCH v2 23/32] test: Remove unused variable FFMPEG_PID_FILE David Gibson
2022-09-08  6:16 ` [PATCH v2 24/32] test: Actually run cleanup function David Gibson
2022-09-08  6:16 ` [PATCH v2 25/32] test: Create common state directories for temporary files David Gibson
2022-09-08  6:16 ` [PATCH v2 26/32] test: Move context temporary files to state dir David Gibson
2022-09-08  6:16 ` [PATCH v2 27/32] test: Dont regnerate small test file in pasta/tcp David Gibson
2022-09-08  6:16 ` [PATCH v2 28/32] test: Use paths in __STATEDIR__ instead of 'temp' and 'tempdir' directives David Gibson
2022-09-08  6:16 ` [PATCH v2 29/32] test: Move pause temporary file to state directory David Gibson
2022-09-08  6:16 ` [PATCH v2 30/32] test: Store pcap files in $LOGDIR instead of /tmp David Gibson
2022-09-08  6:16 ` [PATCH v2 31/32] test: Move pidfiles and nsholder sockets into state directory David Gibson
2022-09-08  6:16 ` [PATCH v2 32/32] test: Move video processing files to $STATEBASE David Gibson

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