diff options
Diffstat (limited to 'runtime/libgcry_common.c')
| -rw-r--r-- | runtime/libgcry_common.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/runtime/libgcry_common.c b/runtime/libgcry_common.c new file mode 100644 index 0000000..1cc56fe --- /dev/null +++ b/runtime/libgcry_common.c @@ -0,0 +1,200 @@ +/* libgcry_common.c + * This file hosts functions both being used by the rsyslog runtime as + * well as tools who do not use the runtime (so we can maintain the + * code at a single place). + * + * Copyright 2013 Adiscon GmbH. + * + * This file is part of rsyslog. + * + * Licensed 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 + * -or- + * see COPYING.ASL20 in the source distribution + * + * 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. + */ +#if HAVE_CONFIG_H +#include "config.h" +#endif +#include <stdio.h> +#include <gcrypt.h> +#include <sys/stat.h> +#include <sys/uio.h> +#include <sys/types.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> + +#include "rsyslog.h" /* we need data typedefs */ +#include "libgcry.h" + + +/* read a key from a key file + * @param[out] key - key buffer, must be freed by caller + * @param[out] keylen - length of buffer + * @returns 0 if OK, something else otherwise (we do not use + * iRet as this is also called from non-rsyslog w/o runtime) + * on error, errno is set and can be queried + * The key length is limited to 64KiB to prevent DoS. + * Note well: key is a blob, not a C string (NUL may be present!) + */ +int +gcryGetKeyFromFile(const char *const fn, char **const key, unsigned *const keylen) +{ + struct stat sb; + int r = -1; + + const int fd = open(fn, O_RDONLY); + if(fd < 0) goto done; + if(fstat(fd, &sb) == -1) goto done; + if(sb.st_size > 64*1024) { + errno = EMSGSIZE; + goto done; + } + if((*key = malloc(sb.st_size)) == NULL) goto done; + if(read(fd, *key, sb.st_size) != sb.st_size) goto done; + *keylen = sb.st_size; + r = 0; +done: + if(fd >= 0) { + close(fd); + } + return r; +} + + +/* execute the child process (must be called in child context + * after fork). + */ + +static void +execKeyScript(char *cmd, int pipefd[]) +{ + char *newargv[] = { NULL }; + char *newenviron[] = { NULL }; + + dup2(pipefd[0], STDIN_FILENO); + dup2(pipefd[1], STDOUT_FILENO); + + /* finally exec child */ +fprintf(stderr, "pre execve: %s\n", cmd); + execve(cmd, newargv, newenviron); + /* switch to? + execlp((char*)program, (char*) program, (char*)arg, NULL); + */ + + /* we should never reach this point, but if we do, we terminate */ + return; +} + + +static int +openPipe(char *cmd, int *fd) +{ + int pipefd[2]; + pid_t cpid; + int r; + + if(pipe(pipefd) == -1) { + r = 1; goto done; + } + + cpid = fork(); + if(cpid == -1) { + r = 1; goto done; + } + + if(cpid == 0) { + /* we are the child */ + execKeyScript(cmd, pipefd); + exit(1); + } + + close(pipefd[1]); + *fd = pipefd[0]; + r = 0; +done: return r; +} + + +/* Read a character from the program's output. */ +// TODO: highly unoptimized version, should be used in buffered +// mode +static int +readProgChar(int fd, char *c) +{ + int r; + if(read(fd, c, 1) != 1) { + r = 1; goto done; + } + r = 0; +done: return r; +} + +/* Read a line from the script. Line is terminated by LF, which + * is NOT put into the buffer. + * buf must be 64KiB + */ +static int +readProgLine(int fd, char *buf) +{ + char c; + int r; + unsigned i; + + for(i = 0 ; i < 64*1024 ; ++i) { + if((r = readProgChar(fd, &c)) != 0) goto done; + if(c == '\n') + break; + buf[i] = c; + }; + if(i >= 64*1024) { + r = 1; goto done; + } + buf[i] = '\0'; + r = 0; +done: return r; +} +static int +readProgKey(int fd, char *buf, unsigned keylen) +{ + char c; + int r; + unsigned i; + + for(i = 0 ; i < keylen ; ++i) { + if((r = readProgChar(fd, &c)) != 0) goto done; + buf[i] = c; + }; + r = 0; +done: return r; +} + +int +gcryGetKeyFromProg(char *cmd, char **key, unsigned *keylen) +{ + int r; + int fd; + char rcvBuf[64*1024]; + + if((r = openPipe(cmd, &fd)) != 0) goto done; + if((r = readProgLine(fd, rcvBuf)) != 0) goto done; + if(strcmp(rcvBuf, "RSYSLOG-KEY-PROVIDER:0")) { + r = 2; goto done; + } + if((r = readProgLine(fd, rcvBuf)) != 0) goto done; + *keylen = atoi(rcvBuf); + if((*key = malloc(*keylen)) == NULL) { + r = -1; goto done; + } + if((r = readProgKey(fd, *key, *keylen)) != 0) goto done; +done: return r; +} |