When data is generated by "normal" T tracers, it should be fine. But it might come from unknown sources and then content might be "strange". So let's validate input data a bit more.
142 lines
4.2 KiB
C
142 lines
4.2 KiB
C
#include "event.h"
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#include "database.h"
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#include "utils.h"
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#include "configuration.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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event get_event(int socket, OBUF *event_buffer, void *database)
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{
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#ifdef T_SEND_TIME
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struct timespec t;
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#endif
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int type;
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int32_t length;
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/* Events type -1 and -2 are special: the tracee sends its version
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* of T_messages.txt using those events.
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* We have to check that the local version of T_messages.txt is identical
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* to the one the tracee uses. We don't report those events to the
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* application.
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*/
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again:
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if (fullread(socket, &length, 4) == -1) goto read_error;
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#ifdef T_SEND_TIME
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if (length < sizeof(struct timespec)) goto error;
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if (fullread(socket, &t, sizeof(struct timespec)) == -1) goto read_error;
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length -= sizeof(struct timespec);
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#endif
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if (length < sizeof(int)) goto error;
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if (fullread(socket, &type, sizeof(int)) == -1) goto read_error;
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length -= sizeof(int);
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if (event_buffer->omaxsize < length) {
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event_buffer->omaxsize = (length + 65535) & ~65535;
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event_buffer->obuf = realloc(event_buffer->obuf, event_buffer->omaxsize);
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if (event_buffer->obuf == NULL) { printf("out of memory\n"); exit(1); }
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}
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if (fullread(socket, event_buffer->obuf, length) == -1) goto read_error;
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event_buffer->osize = length;
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if (type == -1) append_received_config_chunk(event_buffer->obuf, length);
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if (type == -2) verify_config();
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if (type == -1 || type == -2) goto again;
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#ifdef T_SEND_TIME
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return new_event(t, type, length, event_buffer->obuf, database);
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#else
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return new_event(type, length, event_buffer->obuf, database);
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#endif
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error:
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printf("error: bad data in get_event()\n");
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read_error:
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return (event){.type = -1};
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}
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#ifdef T_SEND_TIME
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event new_event(struct timespec sending_time, int type,
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int length, char *buffer, void *database)
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#else
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event new_event(int type, int length, char *buffer, void *database)
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#endif
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{
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database_event_format f;
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event e;
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int i;
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int offset;
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/* arbitrary limit to 1GiB (to simplify size checks) */
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if (length < 0 || length > 1024 * 1024 * 1024) goto fatal;
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#ifdef T_SEND_TIME
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e.sending_time = sending_time;
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#endif
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e.type = type;
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e.buffer = buffer;
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f = get_format(database, type);
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if (f.count > T_MAX_ARGS) {
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printf("fatal: the T trace %s is defined to take %d arguments, but T_MAX_ARGS is %d. "
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"Increase T_MAX_ARGS in event.h and recompile all the tracers (make clean; make).\n",
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event_name_from_id(database, type), f.count, T_MAX_ARGS);
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exit(1);
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}
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e.ecount = f.count;
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offset = 0;
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/* setup offsets */
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/* TODO: speedup (no strcmp, string event to include length at head) */
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for (i = 0; i < f.count; i++) {
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//e.e[i].offset = offset;
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if (!strcmp(f.type[i], "int")) {
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if (offset + 4 > length) goto fatal;
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e.e[i].type = EVENT_INT;
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e.e[i].i = *(int *)(&buffer[offset]);
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offset += 4;
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} else if (!strcmp(f.type[i], "ulong")) {
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if (offset + sizeof(unsigned long) > length) goto fatal;
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e.e[i].type = EVENT_ULONG;
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e.e[i].ul = *(unsigned long *)(&buffer[offset]);
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offset += sizeof(unsigned long);
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} else if (!strcmp(f.type[i], "float")) {
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if (offset + sizeof(float) > length) goto fatal;
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e.e[i].type = EVENT_FLOAT;
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e.e[i].f = *(float *)(&buffer[offset]);
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offset += sizeof(float);
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} else if (!strcmp(f.type[i], "string")) {
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if (offset + 1 > length) goto fatal;
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e.e[i].type = EVENT_STRING;
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e.e[i].s = &buffer[offset];
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while (offset < length && buffer[offset]) offset++;
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if (offset == length) goto fatal;
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offset++;
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} else if (!strcmp(f.type[i], "buffer")) {
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if (offset + sizeof(int) > length) goto fatal;
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int len;
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e.e[i].type = EVENT_BUFFER;
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len = *(int *)(&buffer[offset]);
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if (len <= 0 || offset + len + sizeof(int) > length) goto fatal;
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e.e[i].bsize = len;
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e.e[i].b = &buffer[offset+sizeof(int)];
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offset += len+sizeof(int);
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} else {
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printf("unhandled type '%s'\n", f.type[i]);
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abort();
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}
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}
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if (e.ecount==0) { printf("FORMAT not set in event %d\n", type); abort(); }
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return e;
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fatal:
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printf("fatal: bad buffer in new_event\n");
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abort();
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}
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