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Fix su shell environment setup

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This commit is contained in:
topjohnwu 2018-11-10 02:17:13 -05:00
parent 817350c8c5
commit c61c3ae0e9
1 changed files with 30 additions and 41 deletions
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71
native/jni/su/su_daemon.cpp
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@ -189,26 +189,6 @@ static struct su_info *get_su_info(unsigned uid) {
return info; return info;
} }
static void populate_environment(struct su_request *req) {
struct passwd *pw;
if (req->keepenv)
return;
pw = getpwuid(req->uid);
if (pw) {
setenv("HOME", pw->pw_dir, 1);
if (req->shell)
setenv("SHELL", req->shell, 1);
else
setenv("SHELL", DEFAULT_SHELL, 1);
if (req->login || req->uid) {
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
}
}
}
static void set_identity(unsigned uid) { static void set_identity(unsigned uid) {
/* /*
* Set effective uid back to root, otherwise setres[ug]id will fail * Set effective uid back to root, otherwise setres[ug]id will fail
@ -226,7 +206,7 @@ static void set_identity(unsigned uid) {
} }
void su_daemon_handler(int client, struct ucred *credential) { void su_daemon_handler(int client, struct ucred *credential) {
LOGD("su: request from client: %d\n", client); LOGD("su: request from pid=[%d], client=[%d]\n", credential->pid, client);
su_info *info = get_su_info(credential->uid); su_info *info = get_su_info(credential->uid);
@ -249,7 +229,7 @@ void su_daemon_handler(int client, struct ucred *credential) {
--info->ref; --info->ref;
// Wait result // Wait result
LOGD("su: waiting child: [%d]\n", child); LOGD("su: waiting child pid=[%d]\n", child);
int status, code; int status, code;
if (waitpid(child, &status, 0) > 0) if (waitpid(child, &status, 0) > 0)
@ -257,7 +237,7 @@ void su_daemon_handler(int client, struct ucred *credential) {
else else
code = -1; code = -1;
LOGD("su: return code: [%d]\n", code); LOGD("su: return code=[%d]\n", code);
write(client, &code, sizeof(code)); write(client, &code, sizeof(code));
close(client); close(client);
return; return;
@ -276,22 +256,6 @@ void su_daemon_handler(int client, struct ucred *credential) {
// Become session leader // Become session leader
xsetsid(); xsetsid();
// Migrate environment from client
char path[32], buf[4096];
snprintf(path, sizeof(path), "/proc/%d/cwd", ctx.pid);
xreadlink(path, buf, sizeof(buf));
chdir(buf);
snprintf(path, sizeof(path), "/proc/%d/environ", ctx.pid);
memset(buf, 0, sizeof(buf));
int fd = open(path, O_RDONLY);
read(fd, buf, sizeof(buf));
close(fd);
clearenv();
for (size_t pos = 0; buf[pos];) {
putenv(buf + pos);
pos += strlen(buf + pos) + 1;
}
// Read su_request // Read su_request
xxread(client, &ctx.req, sizeof(su_req_base)); xxread(client, &ctx.req, sizeof(su_req_base));
ctx.req.shell = read_string(client); ctx.req.shell = read_string(client);
@ -380,10 +344,35 @@ void su_daemon_handler(int client, struct ucred *credential) {
argv[2] = ctx.req.command; argv[2] = ctx.req.command;
} }
// Setup shell // Setup environment
umask(022); umask(022);
populate_environment(&ctx.req);
set_identity(ctx.req.uid); set_identity(ctx.req.uid);
char path[32], buf[4096];
snprintf(path, sizeof(path), "/proc/%d/cwd", ctx.pid);
xreadlink(path, buf, sizeof(buf));
chdir(buf);
snprintf(path, sizeof(path), "/proc/%d/environ", ctx.pid);
memset(buf, 0, sizeof(buf));
int fd = open(path, O_RDONLY);
read(fd, buf, sizeof(buf));
close(fd);
clearenv();
for (size_t pos = 0; buf[pos];) {
putenv(buf + pos);
pos += strlen(buf + pos) + 1;
}
if (!ctx.req.keepenv) {
struct passwd *pw;
pw = getpwuid(ctx.req.uid);
if (pw) {
setenv("HOME", pw->pw_dir, 1);
if (ctx.req.login || ctx.req.uid) {
setenv("USER", pw->pw_name, 1);
setenv("LOGNAME", pw->pw_name, 1);
}
setenv("SHELL", ctx.req.shell, 1);
}
}
execvp(ctx.req.shell, (char **) argv); execvp(ctx.req.shell, (char **) argv);
fprintf(stderr, "Cannot execute %s: %s\n", ctx.req.shell, strerror(errno)); fprintf(stderr, "Cannot execute %s: %s\n", ctx.req.shell, strerror(errno));