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 d9e7472..d1afea9 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);
}
}
--
2.37.3