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storageproxyd: Remove setuid, setgid, and capset

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These operations require excessive SELinux and UNIX permissions.

Instead of dropping privileges after starting we will start
storageproxyd as "system" user.

Bug: 205904330
Test: com.android.storage-unittest.td
Change-Id: I0b2503a746c52474c8cc2e1f7a2fbe17c98d6d8b
This commit is contained in:
Tri Vo 2022-07-15 10:23:03 -07:00
parent 45545c68d1
commit 846da873b4
1 changed files with 5 additions and 45 deletions
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50
trusty/storage/proxy/proxy.c
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@ -70,49 +70,6 @@ static void show_usage_and_exit(int code) {
exit(code);
}
static int drop_privs(void) {
struct __user_cap_header_struct capheader;
struct __user_cap_data_struct capdata[2];
if (prctl(PR_SET_KEEPCAPS, 1, 0, 0, 0) < 0) {
return -1;
}
/*
* ensure we're running as the system user
*/
if (setgid(AID_SYSTEM) != 0) {
return -1;
}
if (setuid(AID_SYSTEM) != 0) {
return -1;
}
/*
* drop all capabilities except SYS_RAWIO
*/
memset(&capheader, 0, sizeof(capheader));
memset(&capdata, 0, sizeof(capdata));
capheader.version = _LINUX_CAPABILITY_VERSION_3;
capheader.pid = 0;
capdata[CAP_TO_INDEX(CAP_SYS_RAWIO)].permitted = CAP_TO_MASK(CAP_SYS_RAWIO);
capdata[CAP_TO_INDEX(CAP_SYS_RAWIO)].effective = CAP_TO_MASK(CAP_SYS_RAWIO);
if (capset(&capheader, &capdata[0]) < 0) {
return -1;
}
/*
* No access for group and other. We need execute access for user to create
* an accessible directory.
*/
umask(S_IRWXG | S_IRWXO);
return 0;
}
static int handle_req(struct storage_msg* msg, const void* req, size_t req_len) {
int rc;
@ -260,8 +217,11 @@ static void parse_args(int argc, char* argv[]) {
int main(int argc, char* argv[]) {
int rc;
/* drop privileges */
if (drop_privs() < 0) return EXIT_FAILURE;
/*
* No access for group and other. We need execute access for user to create
* an accessible directory.
*/
umask(S_IRWXG | S_IRWXO);
/* parse arguments */
parse_args(argc, argv);