mirror of
https://github.com/RGBCube/serenity
synced 2025-07-26 22:27:44 +00:00
Kernel: Add Credentials to hold a set of user and group IDs
This patch adds a new object to hold a Process's user credentials: - UID, EUID, SUID - GID, EGID, SGID, extra GIDs Credentials are immutable and child processes initially inherit the Credentials object from their parent. Whenever a process changes one or more of its user/group IDs, a new Credentials object is constructed. Any code that wants to inspect and act on a set of credentials can now do so without worrying about data races.
This commit is contained in:
Andreas Kling
parent
bec314611d
commit
122d7d9533
11 changed files with 366 additions and 128 deletions
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@ -495,6 +495,42 @@ ErrorOr<void> Process::do_exec(NonnullLockRefPtr<OpenFileDescription> main_progr
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if (has_interpreter)
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main_program_fd_allocation = TRY(allocate_fd());
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auto old_credentials = this->credentials();
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auto new_credentials = old_credentials;
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bool executable_is_setid = false;
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if (!(main_program_description->custody()->mount_flags() & MS_NOSUID)) {
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auto main_program_metadata = main_program_description->metadata();
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auto new_euid = old_credentials->euid();
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auto new_egid = old_credentials->egid();
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auto new_suid = old_credentials->suid();
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auto new_sgid = old_credentials->sgid();
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if (main_program_metadata.is_setuid()) {
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executable_is_setid = true;
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new_euid = main_program_metadata.uid;
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new_suid = main_program_metadata.uid;
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}
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if (main_program_metadata.is_setgid()) {
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executable_is_setid = true;
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new_egid = main_program_metadata.gid;
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new_sgid = main_program_metadata.gid;
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}
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if (executable_is_setid) {
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new_credentials = TRY(Credentials::create(
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old_credentials->uid(),
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old_credentials->gid(),
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new_euid,
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new_egid,
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new_suid,
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new_sgid,
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old_credentials->extra_gids()));
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}
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}
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// We commit to the new executable at this point. There is no turning back!
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// Prevent other processes from attaching to us with ptrace while we're doing this.
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@ -506,24 +542,10 @@ ErrorOr<void> Process::do_exec(NonnullLockRefPtr<OpenFileDescription> main_progr
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kill_threads_except_self();
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bool executable_is_setid = false;
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if (!(main_program_description->custody()->mount_flags() & MS_NOSUID)) {
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auto main_program_metadata = main_program_description->metadata();
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if (main_program_metadata.is_setuid()) {
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executable_is_setid = true;
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ProtectedDataMutationScope scope { *this };
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m_protected_values.euid = main_program_metadata.uid;
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m_protected_values.suid = main_program_metadata.uid;
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}
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if (main_program_metadata.is_setgid()) {
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executable_is_setid = true;
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ProtectedDataMutationScope scope { *this };
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m_protected_values.egid = main_program_metadata.gid;
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m_protected_values.sgid = main_program_metadata.gid;
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}
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{
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ProtectedDataMutationScope scope { *this };
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m_protected_values.credentials = move(new_credentials);
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}
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set_dumpable(!executable_is_setid);
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// We make sure to enter the new address space before destroying the old one.
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@ -56,7 +56,7 @@ ErrorOr<FlatPtr> Process::sys$fork(RegisterState& regs)
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child->m_protected_values.has_promises = m_protected_values.has_promises.load();
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child->m_protected_values.has_execpromises = m_protected_values.has_execpromises.load();
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child->m_protected_values.sid = m_protected_values.sid;
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child->m_protected_values.extra_gids = m_protected_values.extra_gids;
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child->m_protected_values.credentials = m_protected_values.credentials;
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child->m_protected_values.umask = m_protected_values.umask;
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child->m_protected_values.signal_trampoline = m_protected_values.signal_trampoline;
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child->m_protected_values.dumpable = m_protected_values.dumpable;
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@ -36,35 +36,50 @@ ErrorOr<FlatPtr> Process::sys$getegid()
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return egid().value();
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}
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ErrorOr<FlatPtr> Process::sys$getresuid(Userspace<UserID*> ruid, Userspace<UserID*> euid, Userspace<UserID*> suid)
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ErrorOr<FlatPtr> Process::sys$getresuid(Userspace<UserID*> user_ruid, Userspace<UserID*> user_euid, Userspace<UserID*> user_suid)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::stdio));
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TRY(copy_to_user(ruid, &m_protected_values.uid));
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TRY(copy_to_user(euid, &m_protected_values.euid));
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TRY(copy_to_user(suid, &m_protected_values.suid));
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auto credentials = this->credentials();
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auto uid = credentials->uid();
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auto euid = credentials->euid();
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auto suid = credentials->suid();
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TRY(copy_to_user(user_ruid, &uid));
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TRY(copy_to_user(user_euid, &euid));
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TRY(copy_to_user(user_suid, &suid));
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return 0;
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}
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ErrorOr<FlatPtr> Process::sys$getresgid(Userspace<GroupID*> rgid, Userspace<GroupID*> egid, Userspace<GroupID*> sgid)
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ErrorOr<FlatPtr> Process::sys$getresgid(Userspace<GroupID*> user_rgid, Userspace<GroupID*> user_egid, Userspace<GroupID*> user_sgid)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::stdio));
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TRY(copy_to_user(rgid, &m_protected_values.gid));
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TRY(copy_to_user(egid, &m_protected_values.egid));
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TRY(copy_to_user(sgid, &m_protected_values.sgid));
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auto credentials = this->credentials();
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auto gid = credentials->gid();
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auto egid = credentials->egid();
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auto sgid = credentials->sgid();
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TRY(copy_to_user(user_rgid, &gid));
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TRY(copy_to_user(user_egid, &egid));
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TRY(copy_to_user(user_sgid, &sgid));
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return 0;
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}
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ErrorOr<FlatPtr> Process::sys$getgroups(size_t count, Userspace<gid_t*> user_gids)
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ErrorOr<FlatPtr> Process::sys$getgroups(size_t count, Userspace<GroupID*> user_gids)
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{
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::stdio));
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auto credentials = this->credentials();
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if (!count)
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return extra_gids().size();
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if (count != extra_gids().size())
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return credentials->extra_gids().size();
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if (count != credentials->extra_gids().size())
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return EINVAL;
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TRY(copy_to_user(user_gids, extra_gids().data(), sizeof(gid_t) * count));
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TRY(copy_to_user(user_gids, credentials->extra_gids().data(), sizeof(GroupID) * count));
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return 0;
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}
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@ -16,15 +16,26 @@ ErrorOr<FlatPtr> Process::sys$seteuid(UserID new_euid)
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if (new_euid == (uid_t)-1)
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return EINVAL;
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if (new_euid != uid() && new_euid != suid() && !is_superuser())
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auto credentials = this->credentials();
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if (new_euid != credentials->uid() && new_euid != credentials->suid() && !credentials->is_superuser())
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return EPERM;
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if (euid() != new_euid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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credentials->uid(),
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credentials->gid(),
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new_euid,
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credentials->egid(),
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credentials->suid(),
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credentials->sgid(),
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.euid = new_euid;
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if (credentials->euid() != new_euid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -36,14 +47,26 @@ ErrorOr<FlatPtr> Process::sys$setegid(GroupID new_egid)
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if (new_egid == (uid_t)-1)
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return EINVAL;
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if (new_egid != gid() && new_egid != sgid() && !is_superuser())
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auto credentials = this->credentials();
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if (new_egid != credentials->gid() && new_egid != credentials->sgid() && !credentials->is_superuser())
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return EPERM;
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if (egid() != new_egid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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credentials->uid(),
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credentials->gid(),
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credentials->euid(),
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new_egid,
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credentials->suid(),
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credentials->sgid(),
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.egid = new_egid;
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if (credentials->egid() != new_egid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -55,16 +78,26 @@ ErrorOr<FlatPtr> Process::sys$setuid(UserID new_uid)
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if (new_uid == (uid_t)-1)
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return EINVAL;
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if (new_uid != uid() && new_uid != euid() && !is_superuser())
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auto credentials = this->credentials();
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if (new_uid != credentials->uid() && new_uid != credentials->euid() && !credentials->is_superuser())
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return EPERM;
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if (euid() != new_uid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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new_uid,
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credentials->gid(),
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new_uid,
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credentials->egid(),
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new_uid,
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credentials->sgid(),
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.uid = new_uid;
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m_protected_values.euid = new_uid;
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m_protected_values.suid = new_uid;
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if (credentials->euid() != new_uid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -76,16 +109,26 @@ ErrorOr<FlatPtr> Process::sys$setgid(GroupID new_gid)
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if (new_gid == (uid_t)-1)
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return EINVAL;
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if (new_gid != gid() && new_gid != egid() && !is_superuser())
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auto credentials = this->credentials();
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if (new_gid != credentials->gid() && new_gid != credentials->egid() && !credentials->is_superuser())
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return EPERM;
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if (egid() != new_gid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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credentials->uid(),
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new_gid,
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credentials->euid(),
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new_gid,
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credentials->suid(),
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new_gid,
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.gid = new_gid;
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m_protected_values.egid = new_gid;
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m_protected_values.sgid = new_gid;
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if (credentials->egid() != new_gid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -94,24 +137,35 @@ ErrorOr<FlatPtr> Process::sys$setreuid(UserID new_ruid, UserID new_euid)
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::id));
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if (new_ruid == (uid_t)-1)
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new_ruid = uid();
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if (new_euid == (uid_t)-1)
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new_euid = euid();
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auto credentials = this->credentials();
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auto ok = [this](UserID id) { return id == uid() || id == euid() || id == suid(); };
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if (new_ruid == (uid_t)-1)
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new_ruid = credentials->uid();
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if (new_euid == (uid_t)-1)
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new_euid = credentials->euid();
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auto ok = [&credentials](UserID id) { return id == credentials->uid() || id == credentials->euid() || id == credentials->suid(); };
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if (!ok(new_ruid) || !ok(new_euid))
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return EPERM;
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if (new_ruid < (uid_t)-1 || new_euid < (uid_t)-1)
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return EINVAL;
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if (euid() != new_euid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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new_ruid,
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credentials->gid(),
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new_euid,
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credentials->egid(),
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credentials->suid(),
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credentials->sgid(),
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.uid = new_ruid;
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m_protected_values.euid = new_euid;
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if (credentials->euid() != new_euid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -120,24 +174,34 @@ ErrorOr<FlatPtr> Process::sys$setresuid(UserID new_ruid, UserID new_euid, UserID
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::id));
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if (new_ruid == (uid_t)-1)
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new_ruid = uid();
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if (new_euid == (uid_t)-1)
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new_euid = euid();
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if (new_suid == (uid_t)-1)
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new_suid = suid();
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auto credentials = this->credentials();
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auto ok = [this](UserID id) { return id == uid() || id == euid() || id == suid(); };
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if ((!ok(new_ruid) || !ok(new_euid) || !ok(new_suid)) && !is_superuser())
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if (new_ruid == (uid_t)-1)
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new_ruid = credentials->uid();
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if (new_euid == (uid_t)-1)
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new_euid = credentials->euid();
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if (new_suid == (uid_t)-1)
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new_suid = credentials->suid();
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auto ok = [&credentials](UserID id) { return id == credentials->uid() || id == credentials->euid() || id == credentials->suid(); };
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if ((!ok(new_ruid) || !ok(new_euid) || !ok(new_suid)) && !credentials->is_superuser())
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return EPERM;
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if (euid() != new_euid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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new_ruid,
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credentials->gid(),
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new_euid,
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credentials->egid(),
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new_suid,
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credentials->sgid(),
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.uid = new_ruid;
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m_protected_values.euid = new_euid;
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m_protected_values.suid = new_suid;
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if (credentials->euid() != new_euid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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@ -146,58 +210,84 @@ ErrorOr<FlatPtr> Process::sys$setresgid(GroupID new_rgid, GroupID new_egid, Grou
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VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
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TRY(require_promise(Pledge::id));
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if (new_rgid == (gid_t)-1)
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new_rgid = gid();
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if (new_egid == (gid_t)-1)
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new_egid = egid();
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if (new_sgid == (gid_t)-1)
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new_sgid = sgid();
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auto credentials = this->credentials();
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auto ok = [this](GroupID id) { return id == gid() || id == egid() || id == sgid(); };
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if ((!ok(new_rgid) || !ok(new_egid) || !ok(new_sgid)) && !is_superuser())
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if (new_rgid == (gid_t)-1)
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new_rgid = credentials->gid();
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if (new_egid == (gid_t)-1)
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new_egid = credentials->egid();
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if (new_sgid == (gid_t)-1)
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new_sgid = credentials->sgid();
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auto ok = [&credentials](GroupID id) { return id == credentials->gid() || id == credentials->egid() || id == credentials->sgid(); };
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if ((!ok(new_rgid) || !ok(new_egid) || !ok(new_sgid)) && !credentials->is_superuser())
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return EPERM;
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if (egid() != new_egid)
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set_dumpable(false);
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auto new_credentials = TRY(Credentials::create(
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credentials->uid(),
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new_rgid,
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credentials->euid(),
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new_egid,
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credentials->suid(),
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new_sgid,
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credentials->extra_gids()));
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ProtectedDataMutationScope scope { *this };
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m_protected_values.gid = new_rgid;
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m_protected_values.egid = new_egid;
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m_protected_values.sgid = new_sgid;
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if (credentials->egid() != new_egid)
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set_dumpable(false);
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m_protected_values.credentials = move(new_credentials);
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return 0;
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}
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ErrorOr<FlatPtr> Process::sys$setgroups(size_t count, Userspace<gid_t const*> user_gids)
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ErrorOr<FlatPtr> Process::sys$setgroups(size_t count, Userspace<GroupID const*> user_gids)
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{
|
||||
VERIFY_PROCESS_BIG_LOCK_ACQUIRED(this);
|
||||
TRY(require_promise(Pledge::id));
|
||||
if (!is_superuser())
|
||||
|
||||
auto credentials = this->credentials();
|
||||
|
||||
if (!credentials->is_superuser())
|
||||
return EPERM;
|
||||
|
||||
if (!count) {
|
||||
ProtectedDataMutationScope scope { *this };
|
||||
m_protected_values.extra_gids.clear();
|
||||
m_protected_values.credentials = TRY(Credentials::create(
|
||||
credentials->uid(),
|
||||
credentials->gid(),
|
||||
credentials->euid(),
|
||||
credentials->egid(),
|
||||
credentials->suid(),
|
||||
credentials->sgid(),
|
||||
{}));
|
||||
return 0;
|
||||
}
|
||||
|
||||
Vector<gid_t> new_extra_gids;
|
||||
Vector<GroupID> new_extra_gids;
|
||||
TRY(new_extra_gids.try_resize(count));
|
||||
TRY(copy_n_from_user(new_extra_gids.data(), user_gids, count));
|
||||
|
||||
HashTable<gid_t> unique_extra_gids;
|
||||
HashTable<GroupID> unique_extra_gids;
|
||||
for (auto& extra_gid : new_extra_gids) {
|
||||
if (extra_gid != gid())
|
||||
TRY(unique_extra_gids.try_set(extra_gid));
|
||||
}
|
||||
|
||||
ProtectedDataMutationScope scope { *this };
|
||||
TRY(m_protected_values.extra_gids.try_resize(unique_extra_gids.size()));
|
||||
size_t i = 0;
|
||||
for (auto& extra_gid : unique_extra_gids) {
|
||||
if (extra_gid == gid())
|
||||
continue;
|
||||
m_protected_values.extra_gids[i++] = extra_gid;
|
||||
new_extra_gids.clear_with_capacity();
|
||||
for (auto extra_gid : unique_extra_gids) {
|
||||
TRY(new_extra_gids.try_append(extra_gid));
|
||||
}
|
||||
|
||||
ProtectedDataMutationScope scope { *this };
|
||||
m_protected_values.credentials = TRY(Credentials::create(
|
||||
credentials->uid(),
|
||||
credentials->gid(),
|
||||
credentials->euid(),
|
||||
credentials->egid(),
|
||||
credentials->suid(),
|
||||
credentials->sgid(),
|
||||
new_extra_gids.span()));
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue