sessreg.c

Bug Summary

File:	sessreg.c
Location:	line 293, column 7
Description:	Null pointer passed as an argument to a 'nonnull' parameter

Annotated Source Code

* Permission to use, copy, modify, distribute, and sell this software and its

* documentation for any purpose is hereby granted without fee, provided that

* the above copyright notice appear in all copies and that both that

* copyright notice and this permission notice appear in supporting

* documentation.

* The above copyright notice and this permission notice shall be included

* in all copies or substantial portions of the Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF

* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

* IN NO EVENT SHALL THE OPEN GROUP BE LIABLE FOR ANY CLAIM, DAMAGES OR

* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,

* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR

* OTHER DEALINGS IN THE SOFTWARE.

* Except as contained in this notice, the name of The Open Group shall

* not be used in advertising or otherwise to promote the sale, use or

* other dealings in this Software without prior written authorization

* from The Open Group.

* Permission is hereby granted, free of charge, to any person obtaining a

* copy of this software and associated documentation files (the "Software"),

* to deal in the Software without restriction, including without limitation

* the rights to use, copy, modify, merge, publish, distribute, sublicense,

* and/or sell copies of the Software, and to permit persons to whom the

* Software is furnished to do so, subject to the following conditions:

* The above copyright notice and this permission notice (including the next

* paragraph) shall be included in all copies or substantial portions of the

* Software.

* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

* DEALINGS IN THE SOFTWARE.

* Author: Keith Packard, MIT X Consortium

* Lastlog support and dynamic utmp entry allocation

* by Andreas Stolcke <stolcke@icsi.berkeley.edu>

* sessreg

* simple wtmp/utmp frobber

* usage: sessreg [ -w <wtmp-file> ] [ -u <utmp-file> ]

* [ -l <line> ]

* [ -L <lastlog-file> ] / #ifdef USE_LASTLOG

* [ -h <host-name> ] / BSD only

* [ -s <slot-number> ] [ -x Xservers-file ] / BSD only

* [ -t <ttys-file> ] / BSD only

* [ -a ] [ -d ] user-name

* one of -a or -d must be specified

#include "sessreg.h"

#include <X11/Xos.h>

#include <X11/Xfuncs.h>

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

#ifdef USE_UTMP

static void set_utmp (struct utmp *u, char *line, char *user, char *host,

time_t date, int addp);

#endif

#ifdef USE_UTMPX

static void set_utmpx (struct utmpx *u, const char *line, const char *user,

const char *host, time_t date, int addp);

#endif

static int wflag, uflag, lflag;

static const char *wtmp_file, *utmp_file;

static char *line;

#ifdef USE_UTMPX

#ifdef HAVE_UPDWTMPX1

static const char *wtmpx_file = NULL((void*)0);

#endif

#ifdef HAVE_UTMPXNAME1

static const char *utmpx_file = NULL((void*)0);

100

#endif

101

#endif

102

#ifndef WTMPX_FILE"/var/log/wtmp"

103

#define WTMPX_FILE"/var/log/wtmp" _PATH_WTMPX"/var/log/wtmp"

104

#endif

105

#ifndef UTMPX_FILE"/var/run/utmp"

106

#define UTMPX_FILE"/var/run/utmp" _PATH_UTMPX"/var/run/utmp"

107

#endif

108

109

static int utmp_none, wtmp_none;

110

111

* BSD specific variables. To make life much easier for Xstartup/Xreset

112

* maintainers, these arguments are accepted but ignored for sysV

113

114

static int hflag, xflag, tflag;

115

static char *host_name = NULL((void*)0);

116

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

117

static int sflag;

118

static int slot_number;

119

#endif

120

static char *xservers_file, *ttys_file;

121

static char *user_name;

122

static int aflag, dflag;

123

#ifdef USE_LASTLOG

124

static const char *llog_file;

125

static int llog_none, Lflag;

126

#endif

127

128

static char *program_name;

129

130

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

131

static int findslot (char *line_name, char *host_name, int addp, int slot);

132

static int Xslot (char *ttys_file, char *servers_file, char *tty_line,

133

char *host_name, int addp);

134

#endif

135

136

static int

137

usage (int x)

138

{

139

if (x) {

140

fprintf (stderrstderr, "%s: usage %s {-a -d} [-w wtmp-file] [-u utmp-file]", program_name, program_name);

141

#ifdef USE_LASTLOG

142

fprintf (stderrstderr, " [-L lastlog-file]");

143

#endif

144

fprintf (stderrstderr, "\n");

145

fprintf (stderrstderr, " [-t ttys-file] [-l line-name] [-h host-name]\n");

146

fprintf (stderrstderr, " [-s slot-number] [-x servers-file] user-name\n");

147

exit (1);

148

}

149

return x;

150

}

151

152

static char *

153

getstring (char ***avp, int *flagp)

154

{

155

char **a = *avp;

156

157

usage ((*flagp)++);

158

if (*++*a)

159

return *a;

160

++a;

161

usage (!*a);

162

*avp = a;

163

return *a;

164

}

165

166

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

167

static int

168

syserr (int x, const char *s)

169

{

170

if (x == -1) {

171

perror (s);

172

exit (1);

173

}

174

return x;

175

}

176

#endif

177

178

static int

179

sysnerr (int x, const char *s)

180

{

181

if (x == 0) {

182

perror (s);

183

exit (1);

184

}

185

return x;

186

}

187

188

int

189

main (int argc, char **argv)

190

{

191

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

192

int utmp;

193

#endif

194

#ifndef USE_UTMPX

195

int wtmp;

196

#endif

197

time_t current_time;

198

#ifdef USE_UTMP

199

struct utmp utmp_entry;

200

#endif

201

#ifdef USE_UTMPX

202

struct utmpx utmpx_entry;

203

#endif

204

205

program_name = argv[0];

206

while (*++argv && **argv == '-') {

1	Loop condition is false. Execution continues on line 252

207

switch (*++*argv) {

208

case 'w':

209

wtmp_file = getstring (&argv, &wflag);

210

if (!strcmp (wtmp_file, "none"))

211

wtmp_none = 1;

212

break;

213

case 'u':

214

utmp_file = getstring (&argv, &uflag);

215

if (!strcmp (utmp_file, "none"))

216

utmp_none = 1;

217

break;

218

#ifdef USE_LASTLOG

219

case 'L':

220

llog_file = getstring (&argv, &Lflag);

221

if (!strcmp (llog_file, "none"))

222

llog_none = 1;

223

break;

224

#endif

225

case 't':

226

ttys_file = getstring (&argv, &tflag);

227

break;

228

case 'l':

229

line = getstring (&argv, &lflag);

230

break;

231

case 'h':

232

host_name = getstring (&argv, &hflag);

233

break;

234

case 's':

235

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

236

slot_number = atoi (getstring (&argv, &sflag));

237

#endif

238

break;

239

case 'x':

240

xservers_file = getstring (&argv, &xflag);

241

break;

242

case 'a':

243

aflag++;

244

break;

245

case 'd':

246

dflag++;

247

break;

248

default:

249

usage (1);

250

}

251

}

252

usage (!(user_name = *argv++));

253

usage (*argv != NULL((void*)0));

254

255

* complain if neither aflag nor dflag are set,

256

* or if both are set.

257

258

usage (!(aflag ^ dflag));

259

usage (xflag && !lflag);

260

/* set up default file names */

261

if (!wflag) {

2	Assuming 'wflag' is not equal to 0

3	Taking false branch

262

wtmp_file = WTMP_FILE"/var/log/wtmp";

263

#if defined(USE_UTMPX) && defined(HAVE_UPDWTMPX1)

264

wtmpx_file = WTMPX_FILE"/var/log/wtmp";

265

#endif

266

}

267

#ifndef NO_UTMP

268

if (!uflag) {

4	Assuming 'uflag' is not equal to 0

5	Taking false branch

269

utmp_file = UTMP_FILE"/var/run/utmp";

270

#if defined(USE_UTMPX) && defined(HAVE_UTMPXNAME1)

271

utmpx_file = UTMPX_FILE"/var/run/utmp";

272

#endif

273

}

274

#else

275

utmp_none = 1;

276

#endif

277

#ifdef USE_LASTLOG

278

if (!Lflag)

6	Assuming 'Lflag' is not equal to 0

7	Taking false branch

279

llog_file = LLOG_FILE"/var/log/lastlog";

280

#endif

281

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

282

if (!tflag)

283

ttys_file = TTYS_FILE"/etc/ttys";

284

if (!sflag && !utmp_none) {

285

if (xflag)

286

sysnerr (slot_number = Xslot (ttys_file, xservers_file, line, host_name, aflag), "Xslot");

287

else

288

sysnerr (slot_number = ttyslot (), "ttyslot");

289

}

290

#endif

291

if (!lflag) {

8	Assuming 'lflag' is 0

9	Taking true branch

292

sysnerr ((line = ttyname (0)) != NULL((void*)0), "ttyname");

293

if (strncmp(line, "/dev/", 5) == 0)

10	Null pointer passed as an argument to a 'nonnull' parameter

294

line += 5;

295

}

296

time (&current_time);

297

#ifdef USE_UTMP

298

set_utmp (&utmp_entry, line, user_name, host_name, current_time, aflag);

299

#endif

300

301

#ifdef USE_UTMPX

302

/* need to set utmpxname() before calling set_utmpx() for

303

UtmpxIdOpen to work */

304

# ifdef HAVE_UTMPXNAME1

305

if (utmpx_file != NULL((void*)0)) {

306

utmpxname (utmpx_file);

307

}

308

# endif

309

set_utmpx (&utmpx_entry, line, user_name,

310

host_name, current_time, aflag);

311

#endif

312

313

if (!utmp_none) {

314

#ifdef USE_UTMPX

315

# ifdef HAVE_UTMPXNAME1

316

if (utmpx_file != NULL((void*)0))

317

# endif

318

{

319

setutxent ();

320

(void) getutxid (&utmpx_entry);

321

pututxline (&utmpx_entry);

322

endutxent ();

323

}

324

#endif

325

#ifdef USE_UTMP

326

# ifdef HAVE_PUTUTLINE1

327

utmpname (utmp_file);

328

setutent ();

329

(void) getutid (&utmp_entry);

330

pututline (&utmp_entry);

331

endutent ();

332

# else

333

utmp = open (utmp_file, O_RDWR02);

334

if (utmp != -1) {

335

syserr ((int) lseek (utmp, (long) slot_number * sizeof (struct utmp), 0), "lseek");

336

sysnerr (write (utmp, (char *) &utmp_entry, sizeof (utmp_entry))

337

== sizeof (utmp_entry), "write utmp entry");

338

close (utmp);

339

}

340

# endif

341

#endif /* USE_UTMP */

342

}

343

if (!wtmp_none) {

344

#ifdef USE_UTMPX

345

# ifdef HAVE_UPDWTMPX1

346

if (wtmpx_file != NULL((void*)0)) {

347

updwtmpx(wtmpx_file, &utmpx_entry);

348

}

349

# endif

350

#else

351

wtmp = open (wtmp_file, O_WRONLY01|O_APPEND02000);

352

if (wtmp != -1) {

353

sysnerr (write (wtmp, (char *) &utmp_entry, sizeof (utmp_entry))

354

== sizeof (utmp_entry), "write wtmp entry");

355

close (wtmp);

356

}

357

#endif

358

}

359

#ifdef USE_LASTLOG

360

if (aflag && !llog_none) {

361

int llog;

362

struct passwd *pwd = getpwnam(user_name);

363

364

sysnerr( pwd != NULL((void*)0), "get user id");

365

llog = open (llog_file, O_RDWR02);

366

367

if (llog != -1) {

368

struct lastlog ll;

369

370

sysnerr (lseek(llog, (long) pwd->pw_uid*sizeof(ll), 0)

371

!= -1, "seeking lastlog entry");

372

memset(&ll, 0, sizeof(ll));

373

ll.ll_time = current_time;

374

if (line)

375

(void) strncpy (ll.ll_line, line, sizeof (ll.ll_line));

376

if (host_name)

377

(void) strncpy (ll.ll_host, host_name, sizeof (ll.ll_host));

378

379

sysnerr (write (llog, (char *) &ll, sizeof (ll))

380

== sizeof (ll), "write lastlog entry");

381

close (llog);

382

}

383

}

384

#endif

385

return 0;

386

}

387

388

389

* fill in the appropriate records of the utmp entry

390

391

392

#ifdef USE_UTMP

393

static void

394

set_utmp (struct utmp *u, char *line, char *user, char *host, time_t date, int addp)

395

{

396

memset (u, 0, sizeof (*u));

397

if (line)

398

(void) strncpy (u->ut_line, line, sizeof (u->ut_line));

399

else

400

memset (u->ut_line, 0, sizeof (u->ut_line));

401

if (addp && user)

402

(void) strncpy (u->ut_nameut_user, user, sizeof (u->ut_nameut_user));

403

else

404

memset (u->ut_nameut_user, 0, sizeof (u->ut_nameut_user));

405

#ifdef HAVE_STRUCT_UTMP_UT_ID1

406

if (line) {

407

int i;

408

409

* this is a bit crufty, but

410

* follows the apparent conventions in

411

* the ttys file. ut_id is only 4 bytes

412

* long, and the last 4 bytes of the line

413

* name are written into it, left justified.

414

415

i = strlen (line);

416

if (i >= sizeof (u->ut_id))

417

i -= sizeof (u->ut_id);

418

else

419

i = 0;

420

(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));

421

} else

422

memset (u->ut_id, 0, sizeof (u->ut_id));

423

#endif

424

#ifdef HAVE_STRUCT_UTMP_UT_PID1

425

if (addp)

426

u->ut_pid = getppid ();

427

else

428

u->ut_pid = 0;

429

#endif

430

#ifdef HAVE_STRUCT_UTMP_UT_TYPE1

431

if (addp)

432

u->ut_type = USER_PROCESS7;

433

else

434

u->ut_type = DEAD_PROCESS8;

435

#endif

436

#ifdef HAVE_STRUCT_UTMP_UT_HOST1

437

if (addp && host)

438

(void) strncpy (u->ut_host, host, sizeof (u->ut_host));

439

else

440

memset (u->ut_host, 0, sizeof (u->ut_host));

441

#endif

442

u->ut_timeut_tv.tv_sec = date;

443

}

444

#endif /* USE_UTMP */

445

446

#ifdef USE_UTMPX

447

static int

448

UtmpxIdOpen( char *utmpId )

449

{

450

struct utmpx *u; /* pointer to entry in utmp file */

451

int status = 1; /* return code */

452

453

setutxent();

454

455

while ( (u = getutxent()) != NULL((void*)0) ) {

456

457

if ( (strncmp(u->ut_id, utmpId, 4) == 0 ) &&

458

u->ut_type != DEAD_PROCESS8 ) {

459

460

status = 0;

461

break;

462

}

463

}

464

465

endutxent();

466

return (status);

467

}

468

469

static void

470

set_utmpx (struct utmpx *u, const char *line, const char *user,

471

const char *host, time_t date, int addp)

472

{

473

static const char letters[] =

474

"0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

475

476

if (line)

477

{

478

if(strcmp(line, ":0") == 0)

479

(void) strcpy(u->ut_line, "console");

480

else

481

(void) strncpy (u->ut_line, line, sizeof (u->ut_line));

482

483

strncpy(u->ut_host, line, sizeof(u->ut_host));

484

#ifdef HAVE_STRUCT_UTMPX_UT_SYSLEN

485

u->ut_syslen = strlen(line);

486

#endif

487

}

488

else

489

memset (u->ut_line, 0, sizeof (u->ut_line));

490

if (addp && user)

491

(void) strncpy (u->ut_user, user, sizeof (u->ut_user));

492

else

493

memset (u->ut_user, 0, sizeof (u->ut_user));

494

495

if (line) {

496

int i;

497

498

* this is a bit crufty, but

499

* follows the apparent conventions in

500

* the ttys file. ut_id is only 4 bytes

501

* long, and the last 4 bytes of the line

502

* name are written into it, left justified.

503

504

i = strlen (line);

505

if (i >= sizeof (u->ut_id))

506

i -= sizeof (u->ut_id);

507

else

508

i = 0;

509

(void) strncpy (u->ut_id, line + i, sizeof (u->ut_id));

510

511

/* make sure there is no entry using identical ut_id */

512

if (!UtmpxIdOpen(u->ut_id) && addp) {

513

int limit = sizeof(letters) - 1;

514

int t = 0;

515

516

u->ut_id[1] = line[i];

517

u->ut_id[2] = line[i+1];

518

u->ut_id[3] = line[i+2];

519

do {

520

u->ut_id[0] = letters[t];

521

t++;

522

} while (!UtmpxIdOpen(u->ut_id) && (t < limit));

523

}

524

if (!addp && strstr(line, ":") != NULL((void*)0)) {

525

struct utmpx *tmpu;

526

527

while ( (tmpu = getutxent()) != NULL((void*)0) ) {

528

if ( (strcmp(tmpu->ut_host, line) == 0 ) &&

529

tmpu->ut_type != DEAD_PROCESS8 ) {

530

strncpy(u->ut_id, tmpu->ut_id,

531

sizeof(u->ut_id));

532

break;

533

}

534

}

535

endutxent();

536

}

537

} else

538

memset (u->ut_id, 0, sizeof (u->ut_id));

539

540

if (addp) {

541

u->ut_pid = getppid ();

542

u->ut_type = USER_PROCESS7;

543

} else {

544

u->ut_pid = 0;

545

u->ut_type = DEAD_PROCESS8;

546

}

547

u->ut_tv.tv_sec = date;

548

u->ut_tv.tv_usec = 0;

549

}

550

#endif /* USE_UTMPX */

551

552

#if defined(USE_UTMP) && !defined(HAVE_PUTUTLINE1)

553

554

* compute the slot-number for an X display. This is computed

555

* by counting the lines in /etc/ttys and adding the line-number

556

* that the display appears on in Xservers. This is a poor

557

* design, but is limited by the non-existant interface to utmp.

558

* If host_name is non-NULL, assume it contains the display name,

559

* otherwise use the tty_line argument (i.e., the tty name).

560

561

562

static int

563

Xslot (char *ttys_file, char *servers_file, char *tty_line, char *host_name,

564

int addp)

565

{

566

FILE *ttys, *servers;

567

int c;

568

int slot = 1;

569

int column0 = 1;

570

char servers_line[1024];

571

char disp_name[512];

572

int len;

573

char *pos;

574

575

/* remove screen number from the display name */

576

memset(disp_name, 0, sizeof(disp_name));

577

strncpy(disp_name, host_name ? host_name : tty_line, sizeof(disp_name)-1);

578

pos = strrchr(disp_name, ':');

579

if (pos) {

580

pos = strchr(pos, '.');

581

if (pos)

582

*pos = '\0';

583

}

584

sysnerr ((int)(long)(ttys = fopen (ttys_file, "r")), ttys_file);

585

while ((c = getc (ttys)_IO_getc (ttys)) != EOF(-1))

586

if (c == '\n') {

587

++slot;

588

column0 = 1;

589

} else

590

column0 = 0;

591

if (!column0)

592

++slot;

593

(void) fclose (ttys);

594

sysnerr ((int)(long)(servers = fopen (servers_file, "r")), servers_file);

595

596

len = strlen (disp_name);

597

column0 = 1;

598

while (fgets (servers_line, sizeof (servers_line), servers)) {

599

if (column0 && *servers_line != '#') {

600

if (!strncmp (disp_name, servers_line, len) &&

601

(servers_line[len] == ' ' ||

602

servers_line[len] == '\t'))

603

return slot;

604

++slot;

605

}

606

if (servers_line[strlen(servers_line)-1] != '\n')

607

column0 = 0;

608

else

609

column0 = 1;

610

}

611

612

* display not found in Xservers file - allocate utmp entry dinamically

613

614

return findslot (tty_line, host_name, addp, slot);

615

}

616

617

618

* find a free utmp slot for the X display. This allocates a new entry

619

* past the regular tty entries if necessary, reusing existing entries

620

* (identified by (line,hostname)) if possible.

621

622

static int

623

findslot (char *line_name, char *host_name, int addp, int slot)

624

{

625

int utmp;

626

struct utmp entry;

627

int found = 0;

628

int freeslot = -1;

629

630

syserr(utmp = open (utmp_file, O_RDONLY00), "open utmp");

631

632

633

* first, try to locate a previous entry for this display

634

* also record location of a free slots in case we need a new one

635

636

syserr ((int) lseek (utmp, (long) slot * sizeof (struct utmp), 0), "lseek");

637

638

if (!host_name)

639

host_name = "";

640

641

while (read (utmp, (char *) &entry, sizeof (entry)) == sizeof (entry)) {

642

if (strncmp(entry.ut_line, line_name,

643

sizeof(entry.ut_line)) == 0

644

#ifdef HAVE_STRUCT_UTMP_UT_HOST1

645

646

strncmp(entry.ut_host, host_name,

647

sizeof(entry.ut_host)) == 0

648

#endif

649

) {

650

found = 1;

651

break;

652

}

653

if (freeslot < 0 && *entry.ut_nameut_user == '\0')

654

freeslot = slot;

655

++slot;

656

}

657

658

close (utmp);

659

660

if (found)

661

return slot;

662

else if (!addp)

663

return 0; /* trying to delete a non-existing entry */

664

else if (freeslot < 0)

665

return slot; /* first slot past current entries */

666

else

667

return freeslot;

668

}

669

#endif