X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Frunas.cpp;fp=src%2Fcommon%2Frunas.cpp;h=3c9eea8c33f6be46b9044c673e1fb160408cc22d;hp=0000000000000000000000000000000000000000;hb=a6bc4ca9d659caf016ef932fcd944029737ac57c;hpb=97535efaa975ca52bf02c2d5e76351bfd2e3defa diff --git a/src/common/runas.cpp b/src/common/runas.cpp new file mode 100644 index 000000000..3c9eea8c3 --- /dev/null +++ b/src/common/runas.cpp @@ -0,0 +1,2033 @@ +/* + * Copyright (C) 2011 David Goulet + * Copyright (C) 2011 Mathieu Desnoyers + * Copyright (C) 2019 Jérémie Galarneau + * + * SPDX-License-Identifier: GPL-2.0-only + * + */ + +#define _LGPL_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include + +#include +#include + +#include "runas.h" + +#define GETPW_BUFFER_FALLBACK_SIZE 4096 + +struct run_as_data; +struct run_as_ret; +typedef int (*run_as_fct)(struct run_as_data *data, struct run_as_ret *ret_value); + +enum run_as_cmd { + RUN_AS_MKDIR, + RUN_AS_MKDIRAT, + RUN_AS_MKDIR_RECURSIVE, + RUN_AS_MKDIRAT_RECURSIVE, + RUN_AS_OPEN, + RUN_AS_OPENAT, + RUN_AS_UNLINK, + RUN_AS_UNLINKAT, + RUN_AS_RMDIR, + RUN_AS_RMDIRAT, + RUN_AS_RMDIR_RECURSIVE, + RUN_AS_RMDIRAT_RECURSIVE, + RUN_AS_RENAME, + RUN_AS_RENAMEAT, + RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, + RUN_AS_EXTRACT_SDT_PROBE_OFFSETS, + RUN_AS_GENERATE_FILTER_BYTECODE, +}; + +struct run_as_mkdir_data { + int dirfd; + char path[LTTNG_PATH_MAX]; + mode_t mode; +} LTTNG_PACKED; + +struct run_as_open_data { + int dirfd; + char path[LTTNG_PATH_MAX]; + int flags; + mode_t mode; +} LTTNG_PACKED; + +struct run_as_unlink_data { + int dirfd; + char path[LTTNG_PATH_MAX]; +} LTTNG_PACKED; + +struct run_as_rmdir_data { + int dirfd; + char path[LTTNG_PATH_MAX]; + int flags; /* enum lttng_directory_handle_rmdir_recursive_flags. */ +} LTTNG_PACKED; + +struct run_as_extract_elf_symbol_offset_data { + int fd; + char function[LTTNG_SYMBOL_NAME_LEN]; +} LTTNG_PACKED; + +struct run_as_extract_sdt_probe_offsets_data { + int fd; + char probe_name[LTTNG_SYMBOL_NAME_LEN]; + char provider_name[LTTNG_SYMBOL_NAME_LEN]; +} LTTNG_PACKED; + +struct run_as_generate_filter_bytecode_data { + char filter_expression[LTTNG_FILTER_MAX_LEN]; +} LTTNG_PACKED; + +struct run_as_rename_data { + /* + * [0] = old_dirfd + * [1] = new_dirfd + */ + int dirfds[2]; + char old_path[LTTNG_PATH_MAX]; + char new_path[LTTNG_PATH_MAX]; +} LTTNG_PACKED; + +struct run_as_open_ret { + int fd; +} LTTNG_PACKED; + +struct run_as_extract_elf_symbol_offset_ret { + uint64_t offset; +} LTTNG_PACKED; + +struct run_as_extract_sdt_probe_offsets_ret { + uint32_t num_offset; + uint64_t offsets[LTTNG_KERNEL_ABI_MAX_UPROBE_NUM]; +} LTTNG_PACKED; + +struct run_as_generate_filter_bytecode_ret { + /* A lttng_bytecode_filter struct with 'dynamic' payload. */ + char bytecode[LTTNG_FILTER_MAX_LEN]; +} LTTNG_PACKED; + +struct run_as_data { + enum run_as_cmd cmd; + union { + struct run_as_mkdir_data mkdir; + struct run_as_open_data open; + struct run_as_unlink_data unlink; + struct run_as_rmdir_data rmdir; + struct run_as_rename_data rename; + struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset; + struct run_as_extract_sdt_probe_offsets_data extract_sdt_probe_offsets; + struct run_as_generate_filter_bytecode_data generate_filter_bytecode; + } u; + uid_t uid; + gid_t gid; +} LTTNG_PACKED; + +/* + * The run_as_ret structure holds the returned value and status of the command. + * + * The `u` union field holds the return value of the command; in most cases it + * represents the success or the failure of the command. In more complex + * commands, it holds a computed value. + * + * The _errno field is the errno recorded after the execution of the command. + * + * The _error fields is used the signify that return status of the command. For + * simple commands returning `int` the _error field will be the same as the + * ret_int field. In complex commands, it signify the success or failure of the + * command. + * + */ +struct run_as_ret { + union { + int ret; + struct run_as_open_ret open; + struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset; + struct run_as_extract_sdt_probe_offsets_ret extract_sdt_probe_offsets; + struct run_as_generate_filter_bytecode_ret generate_filter_bytecode; + } u; + int _errno; + bool _error; +} LTTNG_PACKED; + +#define COMMAND_IN_FDS(data_ptr) ({ \ + int *fds = NULL; \ + if (command_properties[data_ptr->cmd].in_fds_offset != -1) { \ + fds = (int *) ((char *) data_ptr + command_properties[data_ptr->cmd].in_fds_offset); \ + } \ + fds; \ +}) + +#define COMMAND_OUT_FDS(cmd, ret_ptr) ({ \ + int *fds = NULL; \ + if (command_properties[cmd].out_fds_offset != -1) { \ + fds = (int *) ((char *) ret_ptr + command_properties[cmd].out_fds_offset); \ + } \ + fds; \ +}) + +#define COMMAND_IN_FD_COUNT(data_ptr) ({ \ + command_properties[data_ptr->cmd].in_fd_count; \ +}) + +#define COMMAND_OUT_FD_COUNT(cmd) ({ \ + command_properties[cmd].out_fd_count; \ +}) + +#define COMMAND_USE_CWD_FD(data_ptr) command_properties[data_ptr->cmd].use_cwd_fd + +struct run_as_command_properties { + /* Set to -1 when not applicable. */ + ptrdiff_t in_fds_offset, out_fds_offset; + unsigned int in_fd_count, out_fd_count; + bool use_cwd_fd; +}; + +static const struct run_as_command_properties command_properties[] = { + { + .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.mkdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd), + .out_fds_offset = offsetof(struct run_as_ret, u.open.fd), + .in_fd_count = 1, + .out_fd_count = 1, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.open.dirfd), + .out_fds_offset = offsetof(struct run_as_ret, u.open.fd), + .in_fd_count = 1, + .out_fd_count = 1, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.unlink.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rmdir.dirfd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds), + .out_fds_offset = -1, + .in_fd_count = 2, + .out_fd_count = 0, + .use_cwd_fd = true, + }, + { + .in_fds_offset = offsetof(struct run_as_data, u.rename.dirfds), + .out_fds_offset = -1, + .in_fd_count = 2, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, + u.extract_elf_symbol_offset.fd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = offsetof(struct run_as_data, + u.extract_sdt_probe_offsets.fd), + .out_fds_offset = -1, + .in_fd_count = 1, + .out_fd_count = 0, + .use_cwd_fd = false, + }, + { + .in_fds_offset = -1, + .out_fds_offset = -1, + .in_fd_count = 0, + .out_fd_count = 0, + .use_cwd_fd = false, + }, +}; + +struct run_as_worker_data { + pid_t pid; /* Worker PID. */ + int sockpair[2]; + char *procname; +}; + +/* Single global worker per process (for now). */ +static run_as_worker_data *global_worker; +/* Lock protecting the worker. */ +static pthread_mutex_t worker_lock = PTHREAD_MUTEX_INITIALIZER; + +#ifdef VALGRIND +static +int use_clone(void) +{ + return 0; +} +#else +static +int use_clone(void) +{ + return !lttng_secure_getenv("LTTNG_DEBUG_NOCLONE"); +} +#endif + +/* + * Create recursively directory using the FULL path. + */ +static +int _mkdirat_recursive(struct run_as_data *data, struct run_as_ret *ret_value) +{ + const char *path; + mode_t mode; + struct lttng_directory_handle *handle; + + path = data->u.mkdir.path; + mode = data->u.mkdir.mode; + + handle = lttng_directory_handle_create_from_dirfd(data->u.mkdir.dirfd); + if (!handle) { + ret_value->_errno = errno; + ret_value->_error = true; + ret_value->u.ret = -1; + goto end; + } + /* Ownership of dirfd is transferred to the handle. */ + data->u.mkdir.dirfd = -1; + /* Safe to call as we have transitioned to the requested uid/gid. */ + ret_value->u.ret = lttng_directory_handle_create_subdirectory_recursive( + handle, path, mode); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _mkdirat(struct run_as_data *data, struct run_as_ret *ret_value) +{ + const char *path; + mode_t mode; + struct lttng_directory_handle *handle; + + path = data->u.mkdir.path; + mode = data->u.mkdir.mode; + + handle = lttng_directory_handle_create_from_dirfd(data->u.mkdir.dirfd); + if (!handle) { + ret_value->u.ret = -1; + ret_value->_errno = errno; + ret_value->_error = true; + goto end; + } + /* Ownership of dirfd is transferred to the handle. */ + data->u.mkdir.dirfd = -1; + /* Safe to call as we have transitioned to the requested uid/gid. */ + ret_value->u.ret = lttng_directory_handle_create_subdirectory( + handle, path, mode); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _open(struct run_as_data *data, struct run_as_ret *ret_value) +{ + int fd; + struct lttng_directory_handle *handle; + + handle = lttng_directory_handle_create_from_dirfd(data->u.open.dirfd); + if (!handle) { + ret_value->_errno = errno; + ret_value->_error = true; + ret_value->u.ret = -1; + goto end; + } + /* Ownership of dirfd is transferred to the handle. */ + data->u.open.dirfd = -1; + + fd = lttng_directory_handle_open_file(handle, + data->u.open.path, data->u.open.flags, + data->u.open.mode); + if (fd < 0) { + ret_value->u.ret = -1; + ret_value->u.open.fd = -1; + } else { + ret_value->u.ret = 0; + ret_value->u.open.fd = fd; + } + + ret_value->_errno = errno; + ret_value->_error = fd < 0; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _unlink(struct run_as_data *data, struct run_as_ret *ret_value) +{ + struct lttng_directory_handle *handle; + + handle = lttng_directory_handle_create_from_dirfd(data->u.unlink.dirfd); + if (!handle) { + ret_value->u.ret = -1; + ret_value->_errno = errno; + ret_value->_error = true; + goto end; + } + + /* Ownership of dirfd is transferred to the handle. */ + data->u.unlink.dirfd = -1; + + ret_value->u.ret = lttng_directory_handle_unlink_file(handle, + data->u.unlink.path); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _rmdir(struct run_as_data *data, struct run_as_ret *ret_value) +{ + struct lttng_directory_handle *handle; + + handle = lttng_directory_handle_create_from_dirfd(data->u.rmdir.dirfd); + if (!handle) { + ret_value->u.ret = -1; + ret_value->_errno = errno; + ret_value->_error = true; + goto end; + } + + /* Ownership of dirfd is transferred to the handle. */ + data->u.rmdir.dirfd = -1; + + ret_value->u.ret = lttng_directory_handle_remove_subdirectory( + handle, data->u.rmdir.path); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _rmdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value) +{ + struct lttng_directory_handle *handle; + + handle = lttng_directory_handle_create_from_dirfd(data->u.rmdir.dirfd); + if (!handle) { + ret_value->u.ret = -1; + ret_value->_errno = errno; + ret_value->_error = true; + goto end; + } + + /* Ownership of dirfd is transferred to the handle. */ + data->u.rmdir.dirfd = -1; + + ret_value->u.ret = lttng_directory_handle_remove_subdirectory_recursive( + handle, data->u.rmdir.path, data->u.rmdir.flags); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + lttng_directory_handle_put(handle); +end: + return ret_value->u.ret; +} + +static +int _rename(struct run_as_data *data, struct run_as_ret *ret_value) +{ + const char *old_path, *new_path; + struct lttng_directory_handle *old_handle = NULL, *new_handle = NULL; + + old_path = data->u.rename.old_path; + new_path = data->u.rename.new_path; + + old_handle = lttng_directory_handle_create_from_dirfd( + data->u.rename.dirfds[0]); + if (!old_handle) { + ret_value->u.ret = -1; + goto end; + } + new_handle = lttng_directory_handle_create_from_dirfd( + data->u.rename.dirfds[1]); + if (!new_handle) { + ret_value->u.ret = -1; + goto end; + } + + /* Ownership of dirfds are transferred to the handles. */ + data->u.rename.dirfds[0] = data->u.rename.dirfds[1] = -1; + + /* Safe to call as we have transitioned to the requested uid/gid. */ + ret_value->u.ret = lttng_directory_handle_rename( + old_handle, old_path, new_handle, new_path); +end: + lttng_directory_handle_put(old_handle); + lttng_directory_handle_put(new_handle); + ret_value->_errno = errno; + ret_value->_error = (ret_value->u.ret) ? true : false; + return ret_value->u.ret; +} + +#ifdef HAVE_ELF_H +static +int _extract_elf_symbol_offset(struct run_as_data *data, + struct run_as_ret *ret_value) +{ + int ret = 0; + uint64_t offset; + + ret_value->_error = false; + ret = lttng_elf_get_symbol_offset(data->u.extract_elf_symbol_offset.fd, + data->u.extract_elf_symbol_offset.function, + &offset); + if (ret) { + DBG("Failed to extract ELF function offset"); + ret_value->_error = true; + } + ret_value->u.extract_elf_symbol_offset.offset = offset; + + return ret; +} + +static +int _extract_sdt_probe_offsets(struct run_as_data *data, + struct run_as_ret *ret_value) +{ + int ret = 0; + uint64_t *offsets = NULL; + uint32_t num_offset; + + ret_value->_error = false; + + /* On success, this call allocates the offsets paramater. */ + ret = lttng_elf_get_sdt_probe_offsets( + data->u.extract_sdt_probe_offsets.fd, + data->u.extract_sdt_probe_offsets.provider_name, + data->u.extract_sdt_probe_offsets.probe_name, + &offsets, &num_offset); + + if (ret) { + DBG("Failed to extract SDT probe offsets"); + ret_value->_error = true; + goto end; + } + + if (num_offset <= 0 || num_offset > LTTNG_KERNEL_ABI_MAX_UPROBE_NUM) { + DBG("Wrong number of probes."); + ret = -1; + ret_value->_error = true; + goto free_offset; + } + + /* Copy the content of the offsets array to the ret struct. */ + memcpy(ret_value->u.extract_sdt_probe_offsets.offsets, + offsets, num_offset * sizeof(uint64_t)); + + ret_value->u.extract_sdt_probe_offsets.num_offset = num_offset; + +free_offset: + free(offsets); +end: + return ret; +} +#else +static +int _extract_elf_symbol_offset(struct run_as_data *data, + struct run_as_ret *ret_value) +{ + ERR("Unimplemented runas command RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET"); + return -1; +} + +static +int _extract_sdt_probe_offsets(struct run_as_data *data, + struct run_as_ret *ret_value) +{ + ERR("Unimplemented runas command RUN_AS_EXTRACT_SDT_PROBE_OFFSETS"); + return -1; +} +#endif + +static +int _generate_filter_bytecode(struct run_as_data *data, + struct run_as_ret *ret_value) { + int ret = 0; + const char *filter_expression = NULL; + struct filter_parser_ctx *ctx = NULL; + + ret_value->_error = false; + + filter_expression = data->u.generate_filter_bytecode.filter_expression; + + if (lttng_strnlen(filter_expression, LTTNG_FILTER_MAX_LEN - 1) == LTTNG_FILTER_MAX_LEN - 1) { + ret_value->_error = true; + ret = -1; + goto end; + } + + ret = filter_parser_ctx_create_from_filter_expression(filter_expression, &ctx); + if (ret < 0) { + ret_value->_error = true; + ret = -1; + goto end; + } + + DBG("Size of bytecode generated: %u bytes.", + bytecode_get_len(&ctx->bytecode->b)); + + /* Copy the lttng_bytecode_filter object to the return structure. */ + memcpy(ret_value->u.generate_filter_bytecode.bytecode, + &ctx->bytecode->b, + sizeof(ctx->bytecode->b) + + bytecode_get_len(&ctx->bytecode->b)); + +end: + if (ctx) { + filter_bytecode_free(ctx); + filter_ir_free(ctx); + filter_parser_ctx_free(ctx); + } + + return ret; +} +static +run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd) +{ + switch (cmd) { + case RUN_AS_MKDIR: + case RUN_AS_MKDIRAT: + return _mkdirat; + case RUN_AS_MKDIR_RECURSIVE: + case RUN_AS_MKDIRAT_RECURSIVE: + return _mkdirat_recursive; + case RUN_AS_OPEN: + case RUN_AS_OPENAT: + return _open; + case RUN_AS_UNLINK: + case RUN_AS_UNLINKAT: + return _unlink; + case RUN_AS_RMDIR: + case RUN_AS_RMDIRAT: + return _rmdir; + case RUN_AS_RMDIR_RECURSIVE: + case RUN_AS_RMDIRAT_RECURSIVE: + return _rmdir_recursive; + case RUN_AS_RENAME: + case RUN_AS_RENAMEAT: + return _rename; + case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET: + return _extract_elf_symbol_offset; + case RUN_AS_EXTRACT_SDT_PROBE_OFFSETS: + return _extract_sdt_probe_offsets; + case RUN_AS_GENERATE_FILTER_BYTECODE: + return _generate_filter_bytecode; + default: + ERR("Unknown command %d", (int) cmd); + return NULL; + } +} + +static +int do_send_fds(int sock, const int *fds, unsigned int fd_count) +{ + ssize_t len; + unsigned int i; + + for (i = 0; i < fd_count; i++) { + if (fds[i] < 0) { + DBG("Attempt to send invalid file descriptor (fd = %i)", + fds[i]); + /* Return 0 as this is not a fatal error. */ + return 0; + } + } + + len = lttcomm_send_fds_unix_sock(sock, fds, fd_count); + return len < 0 ? -1 : 0; +} + +static +int do_recv_fds(int sock, int *fds, unsigned int fd_count) +{ + int ret = 0; + unsigned int i; + ssize_t len; + + len = lttcomm_recv_fds_unix_sock(sock, fds, fd_count); + if (len == 0) { + ret = -1; + goto end; + } else if (len < 0) { + PERROR("Failed to receive file descriptors from socket"); + ret = -1; + goto end; + } + + for (i = 0; i < fd_count; i++) { + if (fds[i] < 0) { + ERR("Invalid file descriptor received from worker (fd = %i)", fds[i]); + /* Return 0 as this is not a fatal error. */ + } + } +end: + return ret; +} + +static +int send_fds_to_worker(const run_as_worker_data *worker, + const struct run_as_data *data) +{ + int ret = 0; + unsigned int i; + + if (COMMAND_USE_CWD_FD(data) || COMMAND_IN_FD_COUNT(data) == 0) { + goto end; + } + + for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) { + if (COMMAND_IN_FDS(data)[i] < 0) { + ERR("Refusing to send invalid fd to worker (fd = %i)", + COMMAND_IN_FDS(data)[i]); + ret = -1; + goto end; + } + } + + ret = do_send_fds(worker->sockpair[0], COMMAND_IN_FDS(data), + COMMAND_IN_FD_COUNT(data)); + if (ret < 0) { + PERROR("Failed to send file descriptor to run-as worker"); + ret = -1; + goto end; + } +end: + return ret; +} + +static +int send_fds_to_master(run_as_worker_data *worker, enum run_as_cmd cmd, + struct run_as_ret *run_as_ret) +{ + int ret = 0; + unsigned int i; + + if (COMMAND_OUT_FD_COUNT(cmd) == 0) { + goto end; + } + + ret = do_send_fds(worker->sockpair[1], COMMAND_OUT_FDS(cmd, run_as_ret), + COMMAND_OUT_FD_COUNT(cmd)); + if (ret < 0) { + PERROR("Failed to send file descriptor to master process"); + goto end; + } + + for (i = 0; i < COMMAND_OUT_FD_COUNT(cmd); i++) { + int fd = COMMAND_OUT_FDS(cmd, run_as_ret)[i]; + if (fd >= 0) { + int ret_close = close(fd); + + if (ret_close < 0) { + PERROR("Failed to close result file descriptor (fd = %i)", + fd); + } + } + } +end: + return ret; +} + +static +int recv_fds_from_worker(const run_as_worker_data *worker, enum run_as_cmd cmd, + struct run_as_ret *run_as_ret) +{ + int ret = 0; + + if (COMMAND_OUT_FD_COUNT(cmd) == 0) { + goto end; + } + + ret = do_recv_fds(worker->sockpair[0], COMMAND_OUT_FDS(cmd, run_as_ret), + COMMAND_OUT_FD_COUNT(cmd)); + if (ret < 0) { + PERROR("Failed to receive file descriptor from run-as worker"); + ret = -1; + } +end: + return ret; +} + +static +int recv_fds_from_master(run_as_worker_data *worker, struct run_as_data *data) +{ + int ret = 0; + + if (COMMAND_USE_CWD_FD(data)) { + unsigned int i; + + for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) { + COMMAND_IN_FDS(data)[i] = AT_FDCWD; + } + goto end; + } + + if (COMMAND_IN_FD_COUNT(data) == 0) { + goto end; + } + + ret = do_recv_fds(worker->sockpair[1], COMMAND_IN_FDS(data), + COMMAND_IN_FD_COUNT(data)); + if (ret < 0) { + PERROR("Failed to receive file descriptors from master process"); + ret = -1; + } +end: + return ret; +} + +static +int cleanup_received_fds(struct run_as_data *data) +{ + int ret = 0, i; + + for (i = 0; i < COMMAND_IN_FD_COUNT(data); i++) { + if (COMMAND_IN_FDS(data)[i] == -1) { + continue; + } + ret = close(COMMAND_IN_FDS(data)[i]); + if (ret) { + PERROR("Failed to close file descriptor received fd in run-as worker"); + goto end; + } + } +end: + return ret; +} + +static int get_user_infos_from_uid( + uid_t uid, char **username, gid_t *primary_gid) +{ + int ret; + char *buf = NULL; + long raw_get_pw_buf_size; + size_t get_pw_buf_size; + struct passwd pwd; + struct passwd *result = NULL; + + /* Fetch the max size for the temporary buffer. */ + errno = 0; + raw_get_pw_buf_size = sysconf(_SC_GETPW_R_SIZE_MAX); + if (raw_get_pw_buf_size < 0) { + if (errno != 0) { + PERROR("Failed to query _SC_GETPW_R_SIZE_MAX"); + goto error; + } + + /* Limit is indeterminate. */ + WARN("Failed to query _SC_GETPW_R_SIZE_MAX as it is " + "indeterminate; falling back to default buffer size"); + raw_get_pw_buf_size = GETPW_BUFFER_FALLBACK_SIZE; + } + + get_pw_buf_size = (size_t) raw_get_pw_buf_size; + + buf = (char *) zmalloc(get_pw_buf_size); + if (buf == NULL) { + PERROR("Failed to allocate buffer to get password file entries"); + goto error; + } + + ret = getpwuid_r(uid, &pwd, buf, get_pw_buf_size, &result); + if (ret < 0) { + PERROR("Failed to get user information for user: uid = %d", + (int) uid); + goto error; + } + + if (result == NULL) { + ERR("Failed to find user information in password entries: uid = %d", + (int) uid); + ret = -1; + goto error; + } + + *username = strdup(result->pw_name); + if (*username == NULL) { + PERROR("Failed to copy user name"); + goto error; + } + + *primary_gid = result->pw_gid; + +end: + free(buf); + return ret; +error: + *username = NULL; + *primary_gid = -1; + ret = -1; + goto end; +} + +static int demote_creds( + uid_t prev_uid, gid_t prev_gid, uid_t new_uid, gid_t new_gid) +{ + int ret = 0; + gid_t primary_gid; + char *username = NULL; + + /* Change the group id. */ + if (prev_gid != new_gid) { + ret = setegid(new_gid); + if (ret < 0) { + PERROR("Failed to set effective group id: new_gid = %d", + (int) new_gid); + goto end; + } + } + + /* Change the user id. */ + if (prev_uid != new_uid) { + ret = get_user_infos_from_uid(new_uid, &username, &primary_gid); + if (ret < 0) { + goto end; + } + + /* + * Initialize the supplementary group access list. + * + * This is needed to handle cases where the supplementary groups + * of the user the process is demoting-to would give it access + * to a given file/folder, but not it's primary group. + * + * e.g + * username: User1 + * Primary Group: User1 + * Secondary group: Disk, Network + * + * mkdir inside the following directory must work since User1 + * is part of the Network group. + * + * drwxrwx--- 2 root Network 4096 Jul 23 17:17 /tmp/my_folder/ + * + * + * The order of the following initgroups and seteuid calls is + * important here; + * Only a root process or one with CAP_SETGID capability can + * call the the initgroups() function. We must initialize the + * supplementary groups before we change the effective + * UID to a less-privileged user. + */ + ret = initgroups(username, primary_gid); + if (ret < 0) { + PERROR("Failed to init the supplementary group access list: " + "username = `%s`, primary gid = %d", username, + (int) primary_gid); + goto end; + } + + ret = seteuid(new_uid); + if (ret < 0) { + PERROR("Failed to set effective user id: new_uid = %d", + (int) new_uid); + goto end; + } + } +end: + free(username); + return ret; +} + +static int promote_creds( + uid_t prev_uid, gid_t prev_gid, uid_t new_uid, gid_t new_gid) +{ + int ret = 0; + gid_t primary_gid; + char *username = NULL; + + /* Change the group id. */ + if (prev_gid != new_gid) { + ret = setegid(new_gid); + if (ret < 0) { + PERROR("Failed to set effective group id: new_gid = %d", + (int) new_gid); + goto end; + } + } + + /* Change the user id. */ + if (prev_uid != new_uid) { + ret = get_user_infos_from_uid(new_uid, &username, &primary_gid); + if (ret < 0) { + goto end; + } + + /* + * seteuid call must be done before the initgroups call because + * we need to be privileged (CAP_SETGID) to call initgroups(). + */ + ret = seteuid(new_uid); + if (ret < 0) { + PERROR("Failed to set effective user id: new_uid = %d", + (int) new_uid); + goto end; + } + + /* + * Initialize the supplementary group access list. + * + * There is a possibility the groups we set in the following + * initgroups() call are not exactly the same as the ones we + * had when we originally demoted. This can happen if the + * /etc/group file is modified after the runas process is + * forked. This is very unlikely. + */ + ret = initgroups(username, primary_gid); + if (ret < 0) { + PERROR("Failed to init the supplementary group access " + "list: username = `%s`, primary gid = %d", + username, (int) primary_gid) + goto end; + } + } +end: + free(username); + return ret; +} + +/* + * Return < 0 on error, 0 if OK, 1 on hangup. + */ +static +int handle_one_cmd(run_as_worker_data *worker) +{ + int ret = 0, promote_ret; + struct run_as_data data = {}; + ssize_t readlen, writelen; + struct run_as_ret sendret = {}; + run_as_fct cmd; + const uid_t prev_ruid = getuid(); + const gid_t prev_rgid = getgid(); + + /* + * Stage 1: Receive run_as_data struct from the master. + * The structure contains the command type and all the parameters needed for + * its execution + */ + readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data, + sizeof(data)); + if (readlen == 0) { + /* hang up */ + ret = 1; + goto end; + } + if (readlen < sizeof(data)) { + PERROR("lttcomm_recv_unix_sock error"); + ret = -1; + goto end; + } + + cmd = run_as_enum_to_fct(data.cmd); + if (!cmd) { + ret = -1; + goto end; + } + + /* + * Stage 2: Receive file descriptor from master. + * Some commands need a file descriptor as input so if it's needed we + * receive the fd using the Unix socket. + */ + ret = recv_fds_from_master(worker, &data); + if (ret < 0) { + PERROR("recv_fd_from_master error"); + ret = -1; + goto end; + } + + ret = demote_creds(prev_ruid, prev_rgid, data.uid, data.gid); + if (ret < 0) { + goto write_return; + } + + /* + * Also set umask to 0 for mkdir executable bit. + */ + umask(0); + + /* + * Stage 3: Execute the command + */ + ret = (*cmd)(&data, &sendret); + if (ret < 0) { + DBG("Execution of command returned an error"); + } + +write_return: + ret = cleanup_received_fds(&data); + if (ret < 0) { + ERR("Error cleaning up FD"); + goto promote_back; + } + + /* + * Stage 4: Send run_as_ret structure to the master. + * This structure contain the return value of the command and the errno. + */ + writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret, + sizeof(sendret)); + if (writelen < sizeof(sendret)) { + PERROR("lttcomm_send_unix_sock error"); + ret = -1; + goto promote_back; + } + + /* + * Stage 5: Send resulting file descriptors to the master. + */ + ret = send_fds_to_master(worker, data.cmd, &sendret); + if (ret < 0) { + DBG("Sending FD to master returned an error"); + } + + ret = 0; + +promote_back: + /* Return to previous uid/gid. */ + promote_ret = promote_creds(data.uid, data.gid, prev_ruid, prev_rgid); + if (promote_ret < 0) { + ERR("Failed to promote back to the initial credentials"); + } + +end: + return ret; +} + +static +int run_as_worker(run_as_worker_data *worker) +{ + int ret; + ssize_t writelen; + struct run_as_ret sendret; + size_t proc_orig_len; + + /* + * Initialize worker. Set a different process cmdline. + */ + proc_orig_len = strlen(worker->procname); + memset(worker->procname, 0, proc_orig_len); + strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len); + + ret = lttng_thread_setname(DEFAULT_RUN_AS_WORKER_NAME); + if (ret && ret != -ENOSYS) { + /* Don't fail as this is not essential. */ + DBG("Failed to set pthread name attribute"); + } + + memset(&sendret, 0, sizeof(sendret)); + + writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret, + sizeof(sendret)); + if (writelen < sizeof(sendret)) { + PERROR("lttcomm_send_unix_sock error"); + ret = EXIT_FAILURE; + goto end; + } + + for (;;) { + ret = handle_one_cmd(worker); + if (ret < 0) { + ret = EXIT_FAILURE; + goto end; + } else if (ret > 0) { + break; + } else { + continue; /* Next command. */ + } + } + ret = EXIT_SUCCESS; +end: + return ret; +} + +static +int run_as_cmd(run_as_worker_data *worker, + enum run_as_cmd cmd, + struct run_as_data *data, + struct run_as_ret *ret_value, + uid_t uid, gid_t gid) +{ + int ret = 0; + ssize_t readlen, writelen; + + /* + * If we are non-root, we can only deal with our own uid. + */ + if (geteuid() != 0) { + if (uid != geteuid()) { + ret = -1; + ret_value->_errno = EPERM; + ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)", + (int) uid, (int) geteuid()); + goto end; + } + } + + data->cmd = cmd; + data->uid = uid; + data->gid = gid; + + /* + * Stage 1: Send the run_as_data struct to the worker process + */ + writelen = lttcomm_send_unix_sock(worker->sockpair[0], data, + sizeof(*data)); + if (writelen < sizeof(*data)) { + PERROR("Error writing message to run_as"); + ret = -1; + ret_value->_errno = EIO; + goto end; + } + + /* + * Stage 2: Send file descriptor to the worker process if needed + */ + ret = send_fds_to_worker(worker, data); + if (ret) { + PERROR("do_send_fd error"); + ret = -1; + ret_value->_errno = EIO; + goto end; + } + + /* + * Stage 3: Wait for the execution of the command + */ + + /* + * Stage 4: Receive the run_as_ret struct containing the return value and + * errno + */ + readlen = lttcomm_recv_unix_sock(worker->sockpair[0], ret_value, + sizeof(*ret_value)); + if (!readlen) { + ERR("Run-as worker has hung-up during run_as_cmd"); + ret = -1; + ret_value->_errno = EIO; + goto end; + } else if (readlen < sizeof(*ret_value)) { + PERROR("Error reading response from run_as"); + ret = -1; + ret_value->_errno = errno; + goto end; + } + + if (ret_value->_error) { + /* Skip stage 5 on error as there will be no fd to receive. */ + goto end; + } + + /* + * Stage 5: Receive file descriptor if needed + */ + ret = recv_fds_from_worker(worker, cmd, ret_value); + if (ret < 0) { + ERR("Error receiving fd"); + ret = -1; + ret_value->_errno = EIO; + } + +end: + return ret; +} + +/* + * This is for debugging ONLY and should not be considered secure. + */ +static +int run_as_noworker(enum run_as_cmd cmd, + struct run_as_data *data, struct run_as_ret *ret_value, + uid_t uid, gid_t gid) +{ + int ret, saved_errno; + mode_t old_mask; + run_as_fct fct; + + fct = run_as_enum_to_fct(cmd); + if (!fct) { + errno = -ENOSYS; + ret = -1; + goto end; + } + old_mask = umask(0); + ret = fct(data, ret_value); + saved_errno = ret_value->_errno; + umask(old_mask); + errno = saved_errno; +end: + return ret; +} + +static +int reset_sighandler(void) +{ + int sig; + + DBG("Resetting run_as worker signal handlers to default"); + for (sig = 1; sig <= 31; sig++) { + (void) signal(sig, SIG_DFL); + } + return 0; +} + +static +void worker_sighandler(int sig) +{ + const char *signame; + + /* + * The worker will inherit its parent's signals since they are part of + * the same process group. However, in the case of SIGINT and SIGTERM, + * we want to give the worker a chance to teardown gracefully when its + * parent closes the command socket. + */ + switch (sig) { + case SIGINT: + signame = "SIGINT"; + break; + case SIGTERM: + signame = "SIGTERM"; + break; + default: + signame = NULL; + } + + if (signame) { + DBG("run_as worker received signal %s", signame); + } else { + DBG("run_as_worker received signal %d", sig); + } +} + +static +int set_worker_sighandlers(void) +{ + int ret = 0; + sigset_t sigset; + struct sigaction sa; + + if ((ret = sigemptyset(&sigset)) < 0) { + PERROR("sigemptyset"); + goto end; + } + + sa.sa_handler = worker_sighandler; + sa.sa_mask = sigset; + sa.sa_flags = 0; + if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) { + PERROR("sigaction SIGINT"); + goto end; + } + + if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) { + PERROR("sigaction SIGTERM"); + goto end; + } + + DBG("run_as signal handler set for SIGTERM and SIGINT"); +end: + return ret; +} + +static +int run_as_create_worker_no_lock(const char *procname, + post_fork_cleanup_cb clean_up_func, + void *clean_up_user_data) +{ + pid_t pid; + int i, ret = 0; + ssize_t readlen; + struct run_as_ret recvret; + run_as_worker_data *worker; + + LTTNG_ASSERT(!global_worker); + if (!use_clone()) { + /* + * Don't initialize a worker, all run_as tasks will be performed + * in the current process. + */ + ret = 0; + goto end; + } + worker = (run_as_worker_data *) zmalloc(sizeof(*worker)); + if (!worker) { + ret = -ENOMEM; + goto end; + } + worker->procname = strdup(procname); + if (!worker->procname) { + ret = -ENOMEM; + goto error_procname_alloc; + } + /* Create unix socket. */ + if (lttcomm_create_anon_unix_socketpair(worker->sockpair) < 0) { + ret = -1; + goto error_sock; + } + + /* Fork worker. */ + pid = fork(); + if (pid < 0) { + PERROR("fork"); + ret = -1; + goto error_fork; + } else if (pid == 0) { + /* Child */ + + reset_sighandler(); + + set_worker_sighandlers(); + + logger_set_thread_name("Run-as worker", true); + + if (clean_up_func) { + if (clean_up_func(clean_up_user_data) < 0) { + ERR("Run-as post-fork clean-up failed, exiting."); + exit(EXIT_FAILURE); + } + } + + /* Just close, no shutdown. */ + if (close(worker->sockpair[0])) { + PERROR("close"); + exit(EXIT_FAILURE); + } + + /* + * Close all FDs aside from STDIN, STDOUT, STDERR and sockpair[1] + * Sockpair[1] is used as a control channel with the master + */ + for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) { + if (i != worker->sockpair[1]) { + (void) close(i); + } + } + + worker->sockpair[0] = -1; + ret = run_as_worker(worker); + if (lttcomm_close_unix_sock(worker->sockpair[1])) { + PERROR("close"); + ret = -1; + } + worker->sockpair[1] = -1; + free(worker->procname); + free(worker); + LOG(ret ? PRINT_ERR : PRINT_DBG, "run_as worker exiting (ret = %d)", ret); + exit(ret ? EXIT_FAILURE : EXIT_SUCCESS); + } else { + /* Parent */ + + /* Just close, no shutdown. */ + if (close(worker->sockpair[1])) { + PERROR("close"); + ret = -1; + goto error_fork; + } + worker->sockpair[1] = -1; + worker->pid = pid; + /* Wait for worker to become ready. */ + readlen = lttcomm_recv_unix_sock(worker->sockpair[0], + &recvret, sizeof(recvret)); + if (readlen < sizeof(recvret)) { + ERR("readlen: %zd", readlen); + PERROR("Error reading response from run_as at creation"); + ret = -1; + goto error_fork; + } + global_worker = worker; + } +end: + return ret; + + /* Error handling. */ +error_fork: + for (i = 0; i < 2; i++) { + if (worker->sockpair[i] < 0) { + continue; + } + if (lttcomm_close_unix_sock(worker->sockpair[i])) { + PERROR("close"); + } + worker->sockpair[i] = -1; + } +error_sock: + free(worker->procname); +error_procname_alloc: + free(worker); + return ret; +} + +static +void run_as_destroy_worker_no_lock(void) +{ + run_as_worker_data *worker = global_worker; + + DBG("Destroying run_as worker"); + if (!worker) { + return; + } + /* Close unix socket */ + DBG("Closing run_as worker socket"); + if (lttcomm_close_unix_sock(worker->sockpair[0])) { + PERROR("close"); + } + worker->sockpair[0] = -1; + /* Wait for worker. */ + for (;;) { + int status; + pid_t wait_ret; + + wait_ret = waitpid(worker->pid, &status, 0); + if (wait_ret < 0) { + if (errno == EINTR) { + continue; + } + PERROR("waitpid"); + break; + } + + if (WIFEXITED(status)) { + LOG(WEXITSTATUS(status) == 0 ? PRINT_DBG : PRINT_ERR, + DEFAULT_RUN_AS_WORKER_NAME " terminated with status code %d", + WEXITSTATUS(status)); + break; + } else if (WIFSIGNALED(status)) { + ERR(DEFAULT_RUN_AS_WORKER_NAME " was killed by signal %d", + WTERMSIG(status)); + break; + } + } + free(worker->procname); + free(worker); + global_worker = NULL; +} + +static +int run_as_restart_worker(run_as_worker_data *worker) +{ + int ret = 0; + char *procname = NULL; + + procname = worker->procname; + + /* Close socket to run_as worker process and clean up the zombie process */ + run_as_destroy_worker_no_lock(); + + /* Create a new run_as worker process*/ + ret = run_as_create_worker_no_lock(procname, NULL, NULL); + if (ret < 0 ) { + ERR("Restarting the worker process failed"); + ret = -1; + goto err; + } +err: + return ret; +} + +static +int run_as(enum run_as_cmd cmd, struct run_as_data *data, + struct run_as_ret *ret_value, uid_t uid, gid_t gid) +{ + int ret, saved_errno; + + pthread_mutex_lock(&worker_lock); + if (use_clone()) { + DBG("Using run_as worker"); + + LTTNG_ASSERT(global_worker); + + ret = run_as_cmd(global_worker, cmd, data, ret_value, uid, gid); + saved_errno = ret_value->_errno; + + /* + * If the worker thread crashed the errno is set to EIO. we log + * the error and start a new worker process. + */ + if (ret == -1 && saved_errno == EIO) { + DBG("Socket closed unexpectedly... " + "Restarting the worker process"); + ret = run_as_restart_worker(global_worker); + if (ret == -1) { + ERR("Failed to restart worker process."); + goto err; + } + } + } else { + DBG("Using run_as without worker"); + ret = run_as_noworker(cmd, data, ret_value, uid, gid); + } +err: + pthread_mutex_unlock(&worker_lock); + return ret; +} + +int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid) +{ + return run_as_mkdirat_recursive(AT_FDCWD, path, mode, uid, gid); +} + +int run_as_mkdirat_recursive(int dirfd, const char *path, mode_t mode, + uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, (int) mode, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.mkdir.path, path, + sizeof(data.u.mkdir.path)); + if (ret) { + ERR("Failed to copy path argument of mkdirat recursive command"); + goto error; + } + data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0'; + data.u.mkdir.mode = mode; + data.u.mkdir.dirfd = dirfd; + run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR_RECURSIVE : RUN_AS_MKDIRAT_RECURSIVE, + &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid) +{ + return run_as_mkdirat(AT_FDCWD, path, mode, uid, gid); +} + +int run_as_mkdirat(int dirfd, const char *path, mode_t mode, + uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("mkdirat() recursive fd = %d%s, path = %s, mode = %d, uid = %d, gid = %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, (int) mode, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.mkdir.path, path, + sizeof(data.u.mkdir.path)); + if (ret) { + ERR("Failed to copy path argument of mkdirat command"); + goto error; + } + data.u.mkdir.path[sizeof(data.u.mkdir.path) - 1] = '\0'; + data.u.mkdir.mode = mode; + data.u.mkdir.dirfd = dirfd; + run_as(dirfd == AT_FDCWD ? RUN_AS_MKDIR : RUN_AS_MKDIRAT, + &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_open(const char *path, int flags, mode_t mode, uid_t uid, + gid_t gid) +{ + return run_as_openat(AT_FDCWD, path, flags, mode, uid, gid); +} + +int run_as_openat(int dirfd, const char *path, int flags, mode_t mode, + uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("openat() fd = %d%s, path = %s, flags = %X, mode = %d, uid %d, gid %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, flags, (int) mode, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.open.path, path, sizeof(data.u.open.path)); + if (ret) { + ERR("Failed to copy path argument of open command"); + goto error; + } + data.u.open.flags = flags; + data.u.open.mode = mode; + data.u.open.dirfd = dirfd; + run_as(dirfd == AT_FDCWD ? RUN_AS_OPEN : RUN_AS_OPENAT, + &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret < 0 ? run_as_ret.u.ret : + run_as_ret.u.open.fd; +error: + return ret; +} + +int run_as_unlink(const char *path, uid_t uid, gid_t gid) +{ + return run_as_unlinkat(AT_FDCWD, path, uid, gid); +} + +int run_as_unlinkat(int dirfd, const char *path, uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("unlinkat() fd = %d%s, path = %s, uid = %d, gid = %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.unlink.path, path, + sizeof(data.u.unlink.path)); + if (ret) { + goto error; + } + data.u.unlink.dirfd = dirfd; + run_as(dirfd == AT_FDCWD ? RUN_AS_UNLINK : RUN_AS_UNLINKAT, &data, + &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_rmdir(const char *path, uid_t uid, gid_t gid) +{ + return run_as_rmdirat(AT_FDCWD, path, uid, gid); +} + +int run_as_rmdirat(int dirfd, const char *path, uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("rmdirat() fd = %d%s, path = %s, uid = %d, gid = %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.rmdir.path, path, + sizeof(data.u.rmdir.path)); + if (ret) { + goto error; + } + data.u.rmdir.dirfd = dirfd; + run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR : RUN_AS_RMDIRAT, &data, + &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid, int flags) +{ + return run_as_rmdirat_recursive(AT_FDCWD, path, uid, gid, flags); +} + +int run_as_rmdirat_recursive(int dirfd, const char *path, uid_t uid, gid_t gid, int flags) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("rmdirat() recursive fd = %d%s, path = %s, uid = %d, gid = %d", + dirfd, dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + path, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.rmdir.path, path, + sizeof(data.u.rmdir.path)); + if (ret) { + goto error; + } + data.u.rmdir.dirfd = dirfd; + data.u.rmdir.flags = flags; + run_as(dirfd == AT_FDCWD ? RUN_AS_RMDIR_RECURSIVE : RUN_AS_RMDIRAT_RECURSIVE, + &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_rename(const char *old_name, const char *new_name, uid_t uid, gid_t gid) +{ + return run_as_renameat(AT_FDCWD, old_name, AT_FDCWD, new_name, uid, gid); +} + +int run_as_renameat(int old_dirfd, const char *old_name, + int new_dirfd, const char *new_name, uid_t uid, gid_t gid) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("renameat() old_dirfd = %d%s, old_name = %s, new_dirfd = %d%s, new_name = %s, uid = %d, gid = %d", + old_dirfd, old_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + old_name, + new_dirfd, new_dirfd == AT_FDCWD ? " (AT_FDCWD)" : "", + new_name, (int) uid, (int) gid); + ret = lttng_strncpy(data.u.rename.old_path, old_name, + sizeof(data.u.rename.old_path)); + if (ret) { + goto error; + } + ret = lttng_strncpy(data.u.rename.new_path, new_name, + sizeof(data.u.rename.new_path)); + if (ret) { + goto error; + } + + data.u.rename.dirfds[0] = old_dirfd; + data.u.rename.dirfds[1] = new_dirfd; + run_as(old_dirfd == AT_FDCWD && new_dirfd == AT_FDCWD ? + RUN_AS_RENAME : RUN_AS_RENAMEAT, + &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + ret = run_as_ret.u.ret; +error: + return ret; +} + +int run_as_extract_elf_symbol_offset(int fd, const char* function, + uid_t uid, gid_t gid, uint64_t *offset) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("extract_elf_symbol_offset() on fd=%d and function=%s " + "with for uid %d and gid %d", fd, function, + (int) uid, (int) gid); + + data.u.extract_elf_symbol_offset.fd = fd; + + strncpy(data.u.extract_elf_symbol_offset.function, function, LTTNG_SYMBOL_NAME_LEN - 1); + data.u.extract_elf_symbol_offset.function[LTTNG_SYMBOL_NAME_LEN - 1] = '\0'; + ret = lttng_strncpy(data.u.extract_elf_symbol_offset.function, + function, + sizeof(data.u.extract_elf_symbol_offset.function)); + if (ret) { + goto error; + } + + run_as(RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + if (run_as_ret._error) { + ret = -1; + goto error; + } + + *offset = run_as_ret.u.extract_elf_symbol_offset.offset; +error: + return ret; +} + +int run_as_extract_sdt_probe_offsets(int fd, const char* provider_name, + const char* probe_name, uid_t uid, gid_t gid, + uint64_t **offsets, uint32_t *num_offset) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + + DBG3("extract_sdt_probe_offsets() on fd=%d, probe_name=%s and " + "provider_name=%s with for uid %d and gid %d", fd, + probe_name, provider_name, (int) uid, (int) gid); + + data.u.extract_sdt_probe_offsets.fd = fd; + + ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.probe_name, probe_name, + sizeof(data.u.extract_sdt_probe_offsets.probe_name)); + if (ret) { + goto error; + } + ret = lttng_strncpy(data.u.extract_sdt_probe_offsets.provider_name, + provider_name, + sizeof(data.u.extract_sdt_probe_offsets.provider_name)); + if (ret) { + goto error; + } + + run_as(RUN_AS_EXTRACT_SDT_PROBE_OFFSETS, &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + if (run_as_ret._error) { + ret = -1; + goto error; + } + + *num_offset = run_as_ret.u.extract_sdt_probe_offsets.num_offset; + *offsets = (uint64_t *) zmalloc(*num_offset * sizeof(uint64_t)); + if (!*offsets) { + ret = -ENOMEM; + goto error; + } + + memcpy(*offsets, run_as_ret.u.extract_sdt_probe_offsets.offsets, + *num_offset * sizeof(uint64_t)); +error: + return ret; +} + +int run_as_generate_filter_bytecode(const char *filter_expression, + const struct lttng_credentials *creds, + struct lttng_bytecode **bytecode) +{ + int ret; + struct run_as_data data = {}; + struct run_as_ret run_as_ret = {}; + const struct lttng_bytecode *view_bytecode = NULL; + struct lttng_bytecode *local_bytecode = NULL; + const uid_t uid = lttng_credentials_get_uid(creds); + const gid_t gid = lttng_credentials_get_gid(creds); + + DBG3("generate_filter_bytecode() from expression=\"%s\" for uid %d and gid %d", + filter_expression, (int) uid, (int) gid); + + ret = lttng_strncpy(data.u.generate_filter_bytecode.filter_expression, filter_expression, + sizeof(data.u.generate_filter_bytecode.filter_expression)); + if (ret) { + goto error; + } + + run_as(RUN_AS_GENERATE_FILTER_BYTECODE, &data, &run_as_ret, uid, gid); + errno = run_as_ret._errno; + if (run_as_ret._error) { + ret = -1; + goto error; + } + + view_bytecode = (const struct lttng_bytecode *) run_as_ret.u.generate_filter_bytecode.bytecode; + + local_bytecode = (lttng_bytecode *) zmalloc(sizeof(*local_bytecode) + view_bytecode->len); + if (!local_bytecode) { + ret = -ENOMEM; + goto error; + } + + memcpy(local_bytecode, run_as_ret.u.generate_filter_bytecode.bytecode, + sizeof(*local_bytecode) + view_bytecode->len); + *bytecode = local_bytecode; +error: + return ret; +} + +int run_as_create_worker(const char *procname, + post_fork_cleanup_cb clean_up_func, + void *clean_up_user_data) +{ + int ret; + + pthread_mutex_lock(&worker_lock); + ret = run_as_create_worker_no_lock(procname, clean_up_func, + clean_up_user_data); + pthread_mutex_unlock(&worker_lock); + return ret; +} + +void run_as_destroy_worker(void) +{ + pthread_mutex_lock(&worker_lock); + run_as_destroy_worker_no_lock(); + pthread_mutex_unlock(&worker_lock); +}