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commit cf3781b7f0075d7e369ac27394ebbe11843b67ed Author: Abhishek Mishra <[email protected]> AuthorDate: Wed Aug 12 07:13:36 2026 +0000 sched: add setresuid and setresgid Complete the POSIX credential setters for real/effective/saved UID and GID so login and privilege-drop paths can clear saved-root without relying on setreuid patterns alone. Signed-off-by: Abhishek Mishra <[email protected]> --- libs/libc/unistd/lib_setresgid.c | 69 +++++++++++++++++++++++++++++ libs/libc/unistd/lib_setresuid.c | 68 +++++++++++++++++++++++++++++ sched/group/group_setresgid.c | 92 +++++++++++++++++++++++++++++++++++++++ sched/group/group_setresuid.c | 93 ++++++++++++++++++++++++++++++++++++++++ 4 files changed, 322 insertions(+) diff --git a/libs/libc/unistd/lib_setresgid.c b/libs/libc/unistd/lib_setresgid.c new file mode 100644 index 00000000000..ae0ad16262c --- /dev/null +++ b/libs/libc/unistd/lib_setresgid.c @@ -0,0 +1,69 @@ +/**************************************************************************** + * libs/libc/unistd/lib_setresgid.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <unistd.h> +#include <errno.h> + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: setresgid + * + * Description: + * The setresgid() function sets the real, effective, and saved + * set-group-ID of the calling process. Stub when + * CONFIG_SCHED_USER_IDENTITY is disabled: only root (0) or unchanged + * ((gid_t)-1) values are accepted. + * + * Input Parameters: + * rgid - Real group ID, or (gid_t)-1 to leave unchanged. + * egid - Effective group ID, or (gid_t)-1 to leave unchanged. + * sgid - Saved set-group-ID, or (gid_t)-1 to leave unchanged. + * + * Returned Value: + * Zero if successful and -1 in case of failure, in which case errno is set + * appropriately. + * + ****************************************************************************/ + +int setresgid(gid_t rgid, gid_t egid, gid_t sgid) +{ + /* NuttX only supports the group identity 'root' with a gid value of 0. */ + + if ((rgid == (gid_t)-1 || rgid == 0) && + (egid == (gid_t)-1 || egid == 0) && + (sgid == (gid_t)-1 || sgid == 0)) + { + return 0; + } + + set_errno(EINVAL); + return ERROR; +} diff --git a/libs/libc/unistd/lib_setresuid.c b/libs/libc/unistd/lib_setresuid.c new file mode 100644 index 00000000000..847ded42a7e --- /dev/null +++ b/libs/libc/unistd/lib_setresuid.c @@ -0,0 +1,68 @@ +/**************************************************************************** + * libs/libc/unistd/lib_setresuid.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <unistd.h> +#include <errno.h> + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: setresuid + * + * Description: + * The setresuid() function sets the real, effective, and saved set-user-ID + * of the calling process. Stub when CONFIG_SCHED_USER_IDENTITY is + * disabled: only root (0) or unchanged ((uid_t)-1) values are accepted. + * + * Input Parameters: + * ruid - Real user ID, or (uid_t)-1 to leave unchanged. + * euid - Effective user ID, or (uid_t)-1 to leave unchanged. + * suid - Saved set-user-ID, or (uid_t)-1 to leave unchanged. + * + * Returned Value: + * Zero if successful and -1 in case of failure, in which case errno is set + * appropriately. + * + ****************************************************************************/ + +int setresuid(uid_t ruid, uid_t euid, uid_t suid) +{ + /* NuttX only supports the user identity 'root' with a uid value of 0. */ + + if ((ruid == (uid_t)-1 || ruid == 0) && + (euid == (uid_t)-1 || euid == 0) && + (suid == (uid_t)-1 || suid == 0)) + { + return 0; + } + + set_errno(EINVAL); + return ERROR; +} diff --git a/sched/group/group_setresgid.c b/sched/group/group_setresgid.c new file mode 100644 index 00000000000..825877c1516 --- /dev/null +++ b/sched/group/group_setresgid.c @@ -0,0 +1,92 @@ +/**************************************************************************** + * sched/group/group_setresgid.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <unistd.h> +#include <assert.h> +#include <errno.h> + +#include <sched/sched.h> + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: setresgid + * + * Description: + * setresgid() sets the real, effective, and saved set-group-IDs of the + * calling process. The value (gid_t)-1 + * for any argument leaves that ID unchanged. + * + ****************************************************************************/ + +int setresgid(gid_t rgid, gid_t egid, gid_t sgid) +{ + FAR struct tcb_s *rtcb; + FAR struct task_group_s *rgroup; + gid_t old_rgid; + gid_t old_egid; + gid_t old_sgid; + gid_t new_rgid; + gid_t new_egid; + gid_t new_sgid; + + rtcb = this_task(); + rgroup = rtcb->group; + DEBUGASSERT(rgroup != NULL); + + old_rgid = rgroup->tg_gid; + old_egid = rgroup->tg_egid; + old_sgid = rgroup->tg_sgid; + + new_rgid = (rgid == (gid_t)-1) ? old_rgid : rgid; + new_egid = (egid == (gid_t)-1) ? old_egid : egid; + new_sgid = (sgid == (gid_t)-1) ? old_sgid : sgid; + + /* Non-root euid may only select among current real/effective/saved. */ + + if (rgroup->tg_euid != 0) + { + if ((new_rgid != old_rgid && new_rgid != old_egid && + new_rgid != old_sgid) || + (new_egid != old_rgid && new_egid != old_egid && + new_egid != old_sgid) || + (new_sgid != old_rgid && new_sgid != old_egid && + new_sgid != old_sgid)) + { + set_errno(EPERM); + return ERROR; + } + } + + rgroup->tg_gid = new_rgid; + rgroup->tg_egid = new_egid; + rgroup->tg_sgid = new_sgid; + return OK; +} diff --git a/sched/group/group_setresuid.c b/sched/group/group_setresuid.c new file mode 100644 index 00000000000..ca2d6e32677 --- /dev/null +++ b/sched/group/group_setresuid.c @@ -0,0 +1,93 @@ +/**************************************************************************** + * sched/group/group_setresuid.c + * + * SPDX-License-Identifier: Apache-2.0 + * + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. The + * ASF licenses this file to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance with the + * License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT + * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the + * License for the specific language governing permissions and limitations + * under the License. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include <nuttx/config.h> + +#include <sys/types.h> +#include <unistd.h> +#include <assert.h> +#include <errno.h> + +#include <sched/sched.h> + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: setresuid + * + * Description: + * setresuid() sets the real, effective, and saved set-user-IDs of the + * calling process. The value (uid_t)-1 for any argument leaves that + * ID unchanged. + * + ****************************************************************************/ + +int setresuid(uid_t ruid, uid_t euid, uid_t suid) +{ + FAR struct tcb_s *rtcb; + FAR struct task_group_s *rgroup; + uid_t old_ruid; + uid_t old_euid; + uid_t old_suid; + uid_t new_ruid; + uid_t new_euid; + uid_t new_suid; + + rtcb = this_task(); + rgroup = rtcb->group; + DEBUGASSERT(rgroup != NULL); + + old_ruid = rgroup->tg_uid; + old_euid = rgroup->tg_euid; + old_suid = rgroup->tg_suid; + + new_ruid = (ruid == (uid_t)-1) ? old_ruid : ruid; + new_euid = (euid == (uid_t)-1) ? old_euid : euid; + new_suid = (suid == (uid_t)-1) ? old_suid : suid; + + if (old_euid != 0) + { + /* Unprivileged: each new ID must be one of the current r/e/s UIDs. */ + + if ((new_ruid != old_ruid && new_ruid != old_euid && + new_ruid != old_suid) || + (new_euid != old_ruid && new_euid != old_euid && + new_euid != old_suid) || + (new_suid != old_ruid && new_suid != old_euid && + new_suid != old_suid)) + { + set_errno(EPERM); + return ERROR; + } + } + + rgroup->tg_uid = new_ruid; + rgroup->tg_euid = new_euid; + rgroup->tg_suid = new_suid; + return OK; +}
