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fix shared gid support in getpwnam/getgrnam

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Bug: 18374693
Change-Id: I5353403cbbead6f6abac87bee2cf53a60dba408c
This commit is contained in:
Yabin Cui
2014-11-18 16:14:54 -08:00
parent ee4c8febb7
commit a04c79b9d3
2 changed files with 252 additions and 106 deletions
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120
libc/bionic/stubs.cpp
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@@ -40,10 +40,10 @@
#include "private/android_filesystem_config.h"
#include "private/ErrnoRestorer.h"
#include "private/libc_logging.h"
#include "private/ThreadLocalBuffer.h"
GLOBAL_INIT_THREAD_LOCAL_BUFFER(stubs);
// Thread-specific state for the non-reentrant functions.
static pthread_once_t stubs_once = PTHREAD_ONCE_INIT;
static pthread_key_t stubs_key;
struct stubs_state_t {
passwd passwd_;
group group_;
@@ -113,39 +113,14 @@ int getpwuid_r(uid_t uid, passwd* pwd,
return do_getpw_r(0, NULL, uid, pwd, buf, byte_count, result);
}
static stubs_state_t* stubs_state_alloc() {
stubs_state_t* s = static_cast<stubs_state_t*>(calloc(1, sizeof(*s)));
if (s != NULL) {
s->group_.gr_mem = s->group_members_;
}
return s;
}
static void stubs_state_free(void* ptr) {
stubs_state_t* state = static_cast<stubs_state_t*>(ptr);
free(state);
}
static void __stubs_key_init() {
pthread_key_create(&stubs_key, stubs_state_free);
}
static stubs_state_t* __stubs_state() {
pthread_once(&stubs_once, __stubs_key_init);
stubs_state_t* s = static_cast<stubs_state_t*>(pthread_getspecific(stubs_key));
if (s == NULL) {
s = stubs_state_alloc();
if (s == NULL) {
errno = ENOMEM; // Just in case.
} else {
if (pthread_setspecific(stubs_key, s) != 0) {
stubs_state_free(s);
errno = ENOMEM;
s = NULL;
}
}
LOCAL_INIT_THREAD_LOCAL_BUFFER(stubs_state_t*, stubs, sizeof(stubs_state_t));
if (stubs_tls_buffer != NULL) {
memset(stubs_tls_buffer, 0, sizeof(stubs_state_t));
stubs_tls_buffer->group_.gr_mem = stubs_tls_buffer->group_members_;
}
return s;
return stubs_tls_buffer;
}
static passwd* android_iinfo_to_passwd(stubs_state_t* state,
@@ -167,7 +142,6 @@ static group* android_iinfo_to_group(group* gr,
gr->gr_name = (char*) iinfo->name;
gr->gr_gid = iinfo->aid;
gr->gr_mem[0] = gr->gr_name;
gr->gr_mem[1] = NULL;
return gr;
}
@@ -208,18 +182,27 @@ static group* android_name_to_group(group* gr, const char* name) {
}
// Translate a user/group name to the corresponding user/group id.
// all_a1234 -> 0 * AID_USER + AID_SHARED_GID_START + 1234 (group name only)
// u0_a1234 -> 0 * AID_USER + AID_APP + 1234
// u2_i1000 -> 2 * AID_USER + AID_ISOLATED_START + 1000
// u1_system -> 1 * AID_USER + android_ids['system']
// returns 0 and sets errno to ENOENT in case of error
static unsigned app_id_from_name(const char* name) {
if (name[0] != 'u' || !isdigit(name[1])) {
static unsigned app_id_from_name(const char* name, bool is_group) {
char* end;
unsigned long userid;
bool is_shared_gid = false;
if (is_group && name[0] == 'a' && name[1] == 'l' && name[2] == 'l') {
end = const_cast<char*>(name+3);
userid = 0;
is_shared_gid = true;
} else if (name[0] == 'u' && isdigit(name[1])) {
userid = strtoul(name+1, &end, 10);
} else {
errno = ENOENT;
return 0;
}
char* end;
unsigned long userid = strtoul(name+1, &end, 10);
if (end[0] != '_' || end[1] == 0) {
errno = ENOENT;
return 0;
@@ -227,8 +210,17 @@ static unsigned app_id_from_name(const char* name) {
unsigned long appid = 0;
if (end[1] == 'a' && isdigit(end[2])) {
// end will point to \0 if the strtoul below succeeds.
appid = strtoul(end+2, &end, 10) + AID_APP;
if (is_shared_gid) {
// end will point to \0 if the strtoul below succeeds.
appid = strtoul(end+2, &end, 10) + AID_SHARED_GID_START;
if (appid > AID_SHARED_GID_END) {
errno = ENOENT;
return 0;
}
} else {
// end will point to \0 if the strtoul below succeeds.
appid = strtoul(end+2, &end, 10) + AID_APP;
}
} else if (end[1] == 'i' && isdigit(end[2])) {
// end will point to \0 if the strtoul below succeeds.
appid = strtoul(end+2, &end, 10) + AID_ISOLATED_START;
@@ -263,12 +255,11 @@ static unsigned app_id_from_name(const char* name) {
return (unsigned)(appid + userid*AID_USER);
}
static void print_app_name_from_appid_userid(const uid_t appid,
const uid_t userid, char* buffer, const int bufferlen) {
static void print_app_name_from_uid(const uid_t uid, char* buffer, const int bufferlen) {
const uid_t appid = uid % AID_USER;
const uid_t userid = uid / AID_USER;
if (appid >= AID_ISOLATED_START) {
snprintf(buffer, bufferlen, "u%u_i%u", userid, appid - AID_ISOLATED_START);
} else if (userid == 0 && appid >= AID_SHARED_GID_START) {
snprintf(buffer, bufferlen, "all_a%u", appid - AID_SHARED_GID_START);
} else if (appid < AID_APP) {
for (size_t n = 0; n < android_id_count; n++) {
if (android_ids[n].aid == appid) {
@@ -281,10 +272,23 @@ static void print_app_name_from_appid_userid(const uid_t appid,
}
}
static void print_app_name_from_uid(const uid_t uid, char* buffer, const int bufferlen) {
const uid_t appid = uid % AID_USER;
const uid_t userid = uid / AID_USER;
return print_app_name_from_appid_userid(appid, userid, buffer, bufferlen);
static void print_app_name_from_gid(const gid_t gid, char* buffer, const int bufferlen) {
const uid_t appid = gid % AID_USER;
const uid_t userid = gid / AID_USER;
if (appid >= AID_ISOLATED_START) {
snprintf(buffer, bufferlen, "u%u_i%u", userid, appid - AID_ISOLATED_START);
} else if (userid == 0 && appid >= AID_SHARED_GID_START && appid <= AID_SHARED_GID_END) {
snprintf(buffer, bufferlen, "all_a%u", appid - AID_SHARED_GID_START);
} else if (appid < AID_APP) {
for (size_t n = 0; n < android_id_count; n++) {
if (android_ids[n].aid == appid) {
snprintf(buffer, bufferlen, "u%u_%s", userid, android_ids[n].name);
return;
}
}
} else {
snprintf(buffer, bufferlen, "u%u_a%u", userid, appid - AID_APP);
}
}
// Translate a uid into the corresponding name.
@@ -301,12 +305,9 @@ static passwd* app_id_to_passwd(uid_t uid, stubs_state_t* state) {
return NULL;
}
print_app_name_from_uid(uid, state->app_name_buffer_, sizeof(state->app_name_buffer_));
const uid_t appid = uid % AID_USER;
const uid_t userid = uid / AID_USER;
print_app_name_from_appid_userid(appid, userid, state->app_name_buffer_,
sizeof(state->app_name_buffer_));
if (appid < AID_APP) {
snprintf(state->dir_buffer_, sizeof(state->dir_buffer_), "/");
} else {
@@ -332,14 +333,13 @@ static group* app_id_to_group(gid_t gid, stubs_state_t* state) {
return NULL;
}
print_app_name_from_uid(gid, state->group_name_buffer_,
sizeof(state->group_name_buffer_));
print_app_name_from_gid(gid, state->group_name_buffer_, sizeof(state->group_name_buffer_));
group* gr = &state->group_;
gr->gr_name = state->group_name_buffer_;
gr->gr_gid = gid;
gr->gr_mem[0] = gr->gr_name;
gr->gr_mem[1] = NULL;
return gr;
}
@@ -367,7 +367,7 @@ passwd* getpwnam(const char* login) { // NOLINT: implementing bad function.
if (pw != NULL) {
return pw;
}
return app_id_to_passwd(app_id_from_name(login), state);
return app_id_to_passwd(app_id_from_name(login, false), state);
}
// All users are in just one group, the one passed in.
@@ -395,7 +395,6 @@ group* getgrgid(gid_t gid) { // NOLINT: implementing bad function.
if (gr != NULL) {
return gr;
}
return app_id_to_group(gid, state);
}
@@ -408,8 +407,7 @@ group* getgrnam(const char* name) { // NOLINT: implementing bad function.
if (android_name_to_group(&state->group_, name) != 0) {
return &state->group_;
}
return app_id_to_group(app_id_from_name(name), state);
return app_id_to_group(app_id_from_name(name, true), state);
}
// We don't have an /etc/networks, so all inputs return NULL.