generic-library/bionic
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Add per UID interface support to resolv cache

Browse Source 
Add methods to attach/detach UID ranges to a specific dns cache/interface.

This mirrors the already existing code for attaching specific processes to
specific interfaces but will be used to push all processes from a given
user to a specific cache/interface.

Change-Id: Ic24391e92d3ca46fcb46cc4fc53e13984dec40b3
This commit is contained in:
Chad Brubaker 2013-05-30 13:37:02 -07:00
parent 3010061a53
commit 0c9bb49a9d
2 changed files with 162 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

144
libc/netbsd/resolv/res_cache.c
View File

@ -1258,6 +1258,12 @@ typedef struct resolv_pidiface_info {
char ifname[IF_NAMESIZE + 1];
struct resolv_pidiface_info* next;
} PidIfaceInfo;
typedef struct resolv_uidiface_info {
int low;
int high;
char ifname[IF_NAMESIZE + 1];
struct resolv_uidiface_info* next;
} UidIfaceInfo;
#define HTABLE_VALID(x) ((x) != NULL && (x) != HTABLE_DELETED)
@ -1796,6 +1802,9 @@ static struct resolv_cache_info _res_cache_list;
// List of pid iface pairs
static struct resolv_pidiface_info _res_pidiface_list;
// List of uid iface pairs
static struct resolv_uidiface_info _res_uidiface_list;
// name of the current default inteface
static char _res_default_ifname[IF_NAMESIZE + 1];
@ -1805,6 +1814,9 @@ static pthread_mutex_t _res_cache_list_lock;
// lock protecting the _res_pid_iface_list
static pthread_mutex_t _res_pidiface_list_lock;
// lock protecting the _res_uidiface_list
static pthread_mutex_t _res_uidiface_list_lock;
/* lookup the default interface name */
static char *_get_default_iface_locked();
/* find the first cache that has an associated interface and return the name of the interface */
@ -1839,6 +1851,13 @@ static void _remove_pidiface_info_locked(int pid);
/* get a resolv_pidiface_info structure from _res_pidiface_list with a certain pid */
static struct resolv_pidiface_info* _get_pid_iface_info_locked(int pid);
/* remove a resolv_pidiface_info structure from _res_uidiface_list */
static int _remove_uidiface_info_locked(int low, int high);
/* check if a range [low,high] overlaps with any already existing ranges in the uid=>iface map*/
static int _resolv_check_uid_range_overlap_locked(int low, int high);
/* get a resolv_uidiface_info structure from _res_uidiface_list with a certain uid */
static struct resolv_uidiface_info* _get_uid_iface_info_locked(int uid);
static void
_res_cache_init(void)
{
@ -1852,8 +1871,10 @@ _res_cache_init(void)
memset(&_res_default_ifname, 0, sizeof(_res_default_ifname));
memset(&_res_cache_list, 0, sizeof(_res_cache_list));
memset(&_res_pidiface_list, 0, sizeof(_res_pidiface_list));
memset(&_res_uidiface_list, 0, sizeof(_res_uidiface_list));
pthread_mutex_init(&_res_cache_list_lock, NULL);
pthread_mutex_init(&_res_pidiface_list_lock, NULL);
pthread_mutex_init(&_res_uidiface_list_lock, NULL);
}
struct resolv_cache*
@ -2411,6 +2432,129 @@ _resolv_get_pids_associated_interface(int pid, char* buff, int buffLen)
return len;
}
static int
_remove_uidiface_info_locked(int low, int high) {
struct resolv_uidiface_info* result = &_res_uidiface_list.next;
struct resolv_uidiface_info* prev = NULL;
while (result != NULL && result->low != low && result->high != high) {
prev = result;
result = result->next;
}
if (prev != NULL && result != NULL) {
prev->next = result->next;
free(result);
return 0;
}
errno = EINVAL;
return -1;
}
static struct resolv_uidiface_info*
_get_uid_iface_info_locked(int uid)
{
struct resolv_uidiface_info* result = &_res_uidiface_list.next;
while (result != NULL && !(result->low <= uid && result->high >= uid)) {
result = result->next;
}
return result;
}
static int
_resolv_check_uid_range_overlap_locked(int low, int high)
{
struct resolv_uidiface_info* cur = &_res_uidiface_list.next;
while (cur != NULL) {
if (cur->low <= high && cur->high >= low) {
return -1;
}
cur = cur->next;
}
return 0;
}
int
_resolv_set_iface_for_uid_range(const char* ifname, int low, int high)
{
int rv = 0;
struct resolv_uidiface_info* uidiface_info;
// make sure the uid iface list is created
pthread_once(&_res_cache_once, _res_cache_init);
pthread_mutex_lock(&_res_uidiface_list_lock);
//check that we aren't adding an overlapping range
if (!_resolv_check_uid_range_overlap_locked(low,high)) {
uidiface_info = calloc(sizeof(*uidiface_info), 1);
if (uidiface_info) {
uidiface_info->low = low;
uidiface_info->high = high;
int len = sizeof(uidiface_info->ifname);
strncpy(uidiface_info->ifname, ifname, len - 1);
uidiface_info->ifname[len - 1] = '\0';
uidiface_info->next = _res_uidiface_list.next;
_res_uidiface_list.next = uidiface_info;
XLOG("_resolv_set_iface_for_uid_range: [%d,%d], iface %s\n", low, high, ifname);
} else {
XLOG("_resolv_set_iface_for_uid_range failing calloc\n");
rv = -1;
errno = EINVAL;
}
} else {
XLOG("_resolv_set_iface_for_uid_range range [%d,%d] overlaps\n", low, high);
rv = -1;
errno = EINVAL;
}
pthread_mutex_unlock(&_res_uidiface_list_lock);
return rv;
}
int
_resolv_clear_iface_for_uid_range(int low, int high)
{
pthread_once(&_res_cache_once, _res_cache_init);
pthread_mutex_lock(&_res_uidiface_list_lock);
int rv = _remove_uidiface_info_locked(low, high);
XLOG("_resolv_clear_iface_for_uid_range: low %d high %d\n", low, high);
pthread_mutex_unlock(&_res_uidiface_list_lock);
return rv;
}
int
_resolv_get_uids_associated_interface(int uid, char* buff, int buffLen)
{
int len = 0;
if (!buff) {
return -1;
}
pthread_once(&_res_cache_once, _res_cache_init);
pthread_mutex_lock(&_res_uidiface_list_lock);
struct resolv_uidiface_info* uidiface_info = _get_uid_iface_info_locked(uid);
buff[0] = '\0';
if (uidiface_info) {
len = strlen(uidiface_info->ifname);
if (len < buffLen) {
strncpy(buff, uidiface_info->ifname, len);
buff[len] = '\0';
}
}
XLOG("_resolv_get_uids_associated_interface buff: %s\n", buff);
pthread_mutex_unlock(&_res_uidiface_list_lock);
return len;
}
size_t
_resolv_get_default_iface(char* buff, size_t buffLen)
{

18
libc/private/resolv_iface.h
View File

@ -75,6 +75,24 @@ extern void _resolv_clear_iface_for_pid(int pid);
* buffLen Length of buff. An interface is at most IF_NAMESIZE in length */
extern int _resolv_get_pids_associated_interface(int pid, char* buff, int buffLen);
/** set a uid range to use the name servers of the specified interface
* If [low,high] overlaps with an already existing rule -1 is returned */
extern int _resolv_set_iface_for_uid_range(const char* ifname, int low, int high);
/* clear a uid range from being associated with an interface
* If the range given is not mapped -1 is returned. */
extern int _resolv_clear_iface_for_uid_range(int low, int high);
/** Gets the name of the interface to which the uid is attached.
* On error, -1 is returned.
* If no interface is found, 0 is returned and buff is set to empty ('\0').
* If an interface is found, the name is copied to buff and the length of the name is returned.
* Arguments: uid The uid to find an interface for
* buff A buffer to copy the result to
* buffLen Length of buff. An interface is at most IF_NAMESIZE in length */
extern int _resolv_get_uids_associated_interface(int uid, char* buff, int buffLen);
#endif /* _BIONIC_RESOLV_IFACE_FUNCTIONS_DECLARED */
__END_DECLS