[apparmor] [PATCH v2 4/6] utils: Add the --namespace option to C based aa-exec

[John Johansen]

On 12/17/2015 05:02 PM, Tyler Hicks wrote:
> On 2015-12-17 14:30:58, John Johansen wrote:
>> On 12/16/2015 07:25 PM, Tyler Hicks wrote:
>>> Switch to the policy in the namespace specified by the --namespace
>>> option.
>>>
>>> Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
>>> ---
>>>  binutils/aa_exec.c | 55 +++++++++++++++++++++++++++++++++++++++++++++---------
>>>  1 file changed, 46 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/binutils/aa_exec.c b/binutils/aa_exec.c
>>> index 9bcd62f..a57b4ec 100644
>>> --- a/binutils/aa_exec.c
>>> +++ b/binutils/aa_exec.c
>>> @@ -19,6 +19,7 @@
>>>  #include <errno.h>
>>>  #include <getopt.h>
>>>  #include <libintl.h>
>>> +#include <limits.h>
>>>  #include <stdio.h>
>>>  #include <stdarg.h>
>>>  #include <stdlib.h>
>>> @@ -28,6 +29,7 @@
>>>  #define _(s) gettext(s)
>>>  
>>>  static const char *opt_profile = NULL;
>>> +static const char *opt_namespace = NULL;
>>>  static bool opt_debug = false;
>>>  static bool opt_immediate = false;
>>>  static bool opt_verbose = false;
>>> @@ -49,6 +51,7 @@ static void usage(const char *name, bool error)
>>>  		"\n"
>>>  		"OPTIONS:\n"
>>>  		"  -p PROFILE, --profile=PROFILE		PROFILE to confine <prog> with\n"
>>> +		"  -n NAMESPACE, --namespace=NAMESPACE	NAMESPACE to confine <prog> in\n"
>>>  		"  -d, --debug				show messages with debugging information\n"
>>>  		"  -i, --immediate			change profile immediately instead of at exec\n"
>>>  		"  -v, --verbose				show messages with stats\n"
>>> @@ -112,11 +115,12 @@ static char **parse_args(int argc, char **argv)
>>>  		{"debug", no_argument, 0, 'd'},
>>>  		{"help", no_argument, 0, 'h'},
>>>  		{"profile", required_argument, 0, 'p'},
>>> +		{"namespace", required_argument, 0, 'n'},
>>>  		{"immediate", no_argument, 0, 'i'},
>>>  		{"verbose", no_argument, 0, 'v'},
>>>  	};
>>>  
>>> -	while ((opt = getopt_long(argc, argv, "+dhp:iv", long_opts, NULL)) != -1) {
>>> +	while ((opt = getopt_long(argc, argv, "+dhp:n:iv", long_opts, NULL)) != -1) {
>>>  		switch (opt) {
>>>  		case 'd':
>>>  			opt_debug = true;
>>> @@ -127,6 +131,9 @@ static char **parse_args(int argc, char **argv)
>>>  		case 'p':
>>>  			opt_profile = optarg;
>>>  			break;
>>> +		case 'n':
>>> +			opt_namespace = optarg;
>>> +			break;
>>>  		case 'i':
>>>  			opt_immediate = true;
>>>  			break;
>>> @@ -145,28 +152,58 @@ static char **parse_args(int argc, char **argv)
>>>  	return argv + optind;
>>>  }
>>>  
>>> +static void build_name(char *name, size_t name_len,
>>> +		       const char *namespace, const char *profile)
>>> +{
>>> +	size_t required_len = 1; /* reserve 1 byte for NUL-terminator */
>>> +
>>> +	if (namespace)
>>> +		required_len += 1 + strlen(namespace) + 1; /* :<NAMESPACE>: */
>>> +
>>> +	if (profile)
>>> +		required_len += strlen(profile);
>>> +
>>> +	if (required_len > name_len)
>>> +		error("name too long (%zu > %zu)", required_len, name_len);
>>> +
>>> +	name[0] = '\0';
>>> +
>>> +	if (namespace) {
>>> +		strcat(name, ":");
>>> +		strcat(name, namespace);
>>> +		strcat(name, ":");
>>> +	}
>>> +
>> while this does work, the interface accepts
>>   :<namespace name>:<profile name>
>> and
>>   :<namespace name>://<profile name>
>>
>> if there is an error we are exposing this to the user instead of the more standard
>>   :<namespace name>://
>>
>> I'm not sure it is worth changing, I like the shorter form for the kernel but I
>> think in generally anything exposed to the user should probably try to be
>> consistent, and probably stick with the :// syntax as that is what is used
>> beyond apparmor
> 
> It is a simple change to move to the double slash syntax.
> 
>>
>> also I smell an opportunity for a library fn
> 
> Yeah, I'll keep this in mind as I'm working on the userspace API early
> next year.
> 
>>
>>> +	if (profile)
>>> +		strcat(name, profile);
>>> +}
>>> +
>>>  int main(int argc, char **argv)
>>>  {
>>> +	char name[PATH_MAX];
>>>  	int rc = 0;
>>>  
>>>  	argv = parse_args(argc, argv);
>>>  
>>> -	if (!opt_profile)
>>> +	if (opt_namespace || opt_profile)
>>> +		build_name(name, sizeof(name), opt_namespace, opt_profile);
>>> +	else
>>>  		goto exec;
>>>  
>>>  	if (opt_immediate) {
>>> -		verbose("aa_change_profile(\"%s\")", opt_profile);
>>> -		rc = aa_change_profile(opt_profile);
>>> -		debug("%d = aa_change_profile(\"%s\")", rc, opt_profile);
>>> +		verbose("aa_change_profile(\"%s\")", name);
>>> +		rc = aa_change_profile(name);
>>> +		debug("%d = aa_change_profile(\"%s\")", rc, name);
>>>  	} else {
>>> -		verbose("aa_change_onexec(\"%s\")", opt_profile);
>>> -		rc = aa_change_onexec(opt_profile);
>>> -		debug("%d = aa_change_onexec(\"%s\")", rc, opt_profile);
>>> +		verbose("aa_change_onexec(\"%s\")", name);
>>> +		rc = aa_change_onexec(name);
>>> +		debug("%d = aa_change_onexec(\"%s\")", rc, name);
>>>  	}
>>>  
>>>  	if (rc) {
>>>  		if (errno == ENOENT || errno == EACCES) {
>>> -			error("profile '%s' does not exist", opt_profile);
>>> +			error("%s '%s' does not exist\n",
>>> +			      opt_profile ? "profile" : "namespace", name);
>>
>> this is where we expose it to the user
> 
> Ok, does this extra change to this patch get your ack?
> 
sure

Acked-by: John Johansen <john.johansen at canonical.com>

> 
> diff --git a/binutils/aa_exec.c b/binutils/aa_exec.c
> index a57b4ec..7e73f45 100644
> --- a/binutils/aa_exec.c
> +++ b/binutils/aa_exec.c
> @@ -158,7 +158,7 @@ static void build_name(char *name, size_t name_len,
>  	size_t required_len = 1; /* reserve 1 byte for NUL-terminator */
>  
>  	if (namespace)
> -		required_len += 1 + strlen(namespace) + 1; /* :<NAMESPACE>: */
> +		required_len += 1 + strlen(namespace) + 3; /* :<NAMESPACE>:// */
>  
>  	if (profile)
>  		required_len += strlen(profile);
> @@ -171,7 +171,7 @@ static void build_name(char *name, size_t name_len,
>  	if (namespace) {
>  		strcat(name, ":");
>  		strcat(name, namespace);
> -		strcat(name, ":");
> +		strcat(name, "://");
>  	}
>  
>  	if (profile)
>