| /* ********************************************************** |
| * Copyright (c) 2016-2018 Google, Inc. All rights reserved. |
| * **********************************************************/ |
| |
| /* Dr. Memory: the memory debugger |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; |
| * version 2.1 of the License, and no later version. |
| |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| */ |
| |
| #include "dr_api.h" |
| #include "drsyscall.h" |
| #include "drsyscall_os.h" |
| #include "drsyscall_windows.h" |
| |
| static const char * |
| double_strchr(const char *s, char c1, char c2) |
| { |
| while (*s != '\0') { |
| if (*s == c1 || *s == c2) { |
| return s; |
| } |
| ++s; |
| } |
| return NULL; |
| } |
| |
| /* i#1908: we support loading numbers from a file. The file format is documented |
| * in drsyscall.h. |
| * We support carriage returns and a missing trailing newline, which are common |
| * when saving from our URL by pasting into notepad. |
| */ |
| bool |
| read_sysnum_file(void *drcontext, const char *sysnum_file, module_data_t *ntdll_data) |
| { |
| drmf_status_t status = DRMF_ERROR_INVALID_PARAMETER; |
| file_t f; |
| void *map = NULL; |
| bool ok; |
| uint64 map_size; |
| size_t actual_size; |
| const char *line, *search; |
| int val; |
| char name[MAXIMUM_PATH]; |
| drsys_sysnum_t num_from_wrapper; |
| |
| f = dr_open_file(sysnum_file, DR_FILE_READ); |
| if (f == INVALID_FILE) { |
| LOG(SYSCALL_VERBOSE, "syscall file %s not found\n", sysnum_file); |
| goto read_sysnum_file_done; |
| } |
| LOG(SYSCALL_VERBOSE, "processing syscall file %s\n", sysnum_file); |
| ok = dr_file_size(f, &map_size); |
| if (ok) { |
| actual_size = (size_t)map_size; |
| ASSERT(actual_size == map_size, "file size too large"); |
| map = dr_map_file(f, &actual_size, 0, NULL, DR_MEMPROT_READ, 0); |
| } |
| if (!ok || map == NULL || actual_size < map_size) |
| goto read_sysnum_file_done; |
| if (strncmp((char *)map, DRSYS_SYSNUM_FILE_HEADER, |
| strlen(DRSYS_SYSNUM_FILE_HEADER)) != 0) |
| goto read_sysnum_file_done; |
| /* ntdll's sscanf is unsafe for mmap (i#1057) */ |
| line = (char *)map + strlen(DRSYS_SYSNUM_FILE_HEADER) + 1 /* skip \n */; |
| if (*line == '\n') /* if there was \r */ |
| line++; |
| if (dr_sscanf(line, "%d", &val) != 1 || |
| /* neither forward nor backward compatible */ |
| val != DRSYS_SYSNUM_FILE_VERSION) { |
| status = DRMF_ERROR_INCOMPATIBLE_VERSION; |
| goto read_sysnum_file_done; |
| } |
| /* XXX: what we want is strnchr to which we can pass a size to avoid going |
| * off the end of the map. That should only happen for an ill-formed file |
| * so we live with the chance of a crash for now. |
| */ |
| line = strchr(line, '\n'); |
| if (line == NULL || line - map > actual_size) |
| goto read_sysnum_file_done; |
| line++; |
| search = double_strchr(line, '\r', '\n'); |
| if (search == NULL || search - map > actual_size || |
| search - line >= BUFFER_SIZE_ELEMENTS(name)) |
| goto read_sysnum_file_done; |
| strncpy(name, line, search - line); |
| name[search - line] = '\0'; |
| LOG(SYSCALL_VERBOSE, "syscall file: index name is %s\n", name); |
| |
| ok = syscall_num_from_name(drcontext, ntdll_data, name, NULL, false/*exported*/, |
| &num_from_wrapper); |
| if (!ok) |
| goto read_sysnum_file_done; |
| LOG(SYSCALL_VERBOSE, "syscall file: index num is 0x%x\n", num_from_wrapper.number); |
| |
| /* Originally my design was to store the offset for each list at the top, |
| * to avoid this scan, but once it was clear that it is not simple to |
| * download a text file on Windows 10 and it is likely to end up copy-pasted |
| * with CRLF and other changes, relying on offsets is too fragile. |
| */ |
| do { |
| search = strstr(line, "\nSTART=0x"); |
| LOG(SYSCALL_VERBOSE, "syscall file: examining %.16s\n", |
| search == NULL ? "<null>" : search+1); |
| if (search == NULL || search - map > actual_size) |
| goto read_sysnum_file_done; |
| if (dr_sscanf(search+1, "START=0x%x", &val) != 1) |
| goto read_sysnum_file_done; |
| if (num_from_wrapper.number == val) { |
| LOG(SYSCALL_VERBOSE, "syscall file: found target list\n"); |
| break; |
| } |
| line = strchr(search+1, '\n'); |
| if (line == NULL || line - map > actual_size) |
| goto read_sysnum_file_done; |
| } while (search - map < actual_size); |
| |
| line = strchr(search+1, '\n'); |
| if (line == NULL || line - map > actual_size) |
| goto read_sysnum_file_done; |
| line++; |
| |
| while (strncmp(line, DRSYS_SYSNUM_FILE_FOOTER, |
| strlen(DRSYS_SYSNUM_FILE_FOOTER)) != 0) { |
| search = strchr(line, '='); |
| if (search == NULL || search - map > actual_size || |
| search - line >= BUFFER_SIZE_ELEMENTS(name)) |
| goto read_sysnum_file_done; |
| strncpy(name, line, search - line); |
| name[search - line] = '\0'; |
| /* Sanity check in case offs is wrong */ |
| if (name[0] < 'A' || name[0] > 'Z') |
| goto read_sysnum_file_done; |
| line = search + 1; |
| if (dr_sscanf(line, "0x%x", &val) != 1) |
| goto read_sysnum_file_done; |
| name2num_record(name, val, true/*dup the string*/); |
| line = strchr(line, '\n'); |
| /* Handle a missing trailing newline */ |
| if (line == NULL && strncmp(line, DRSYS_SYSNUM_FILE_FOOTER, |
| strlen(DRSYS_SYSNUM_FILE_FOOTER)) == 0) |
| break; |
| if (line == NULL || line - map > actual_size) |
| goto read_sysnum_file_done; |
| line++; |
| } |
| |
| status = DRMF_SUCCESS; |
| read_sysnum_file_done: |
| DOLOG(SYSCALL_VERBOSE, { |
| if (status != DRMF_SUCCESS) |
| LOG(SYSCALL_VERBOSE, "failed to parse syscall file %s\n", sysnum_file); |
| }); |
| if (map != NULL) |
| dr_unmap_file(map, actual_size); |
| if (f != INVALID_FILE) |
| dr_close_file(f); |
| return status; |
| } |
