The Tor Browser: security/nss/cmd/shlibsign/mangle/mangle.c@141e0f1194b1

     1 /* This Source Code Form is subject to the terms of the Mozilla Public

     2  * License, v. 2.0. If a copy of the MPL was not distributed with this

     3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     5 /*

     6  * Test program to mangle 1 bit in a binary

     7  */

     9 #include "nspr.h"

    10 #include "plstr.h"

    11 #include "plgetopt.h"

    12 #include "prio.h"

    14 static PRFileDesc *pr_stderr;

    15 static void

    16 usage (char *program_name)

    17 {

    19     PR_fprintf (pr_stderr, "Usage:");

    20     PR_fprintf (pr_stderr, "%s -i shared_library_name -o byte_offset -b bit\n", program_name);

    21 }

    24 int

    25 main (int argc, char **argv)

    26 {

    27     /* buffers and locals */

    28     PLOptState	*optstate;

    29     char	*programName;

    30     char	cbuf;

    32     /* parameter set variables */

    33     const char  *libFile = NULL;

    34     int bitOffset = -1;

    36     /* return values */

    37     int		 retval = 2;  /* 0 - test succeeded.

    38 			       * 1 - illegal args

    39 			       * 2 - function failed */

    40     PRFileDesc *fd = NULL;

    41     int bytesRead;

    42     int bytesWritten;

    43     PROffset32   offset = -1;

    44     PROffset32   pos;

    46     programName = PL_strrchr(argv[0], '/');

    47     programName = programName ? (programName + 1) : argv[0];

    49     pr_stderr = PR_STDERR;

    51     optstate = PL_CreateOptState (argc, argv, "i:o:b:");

    52     if (optstate == NULL) {

    53 	return 1;

    54     }

    56     while (PL_GetNextOpt (optstate) == PL_OPT_OK) {

    57 	switch (optstate->option) {

    58           case 'i':

    59             libFile = optstate->value;

    60             break;

    62           case 'o':

    63             offset = atoi(optstate->value);

    64             break;

    66           case 'b':

    67             bitOffset = atoi(optstate->value);

    68             break;

    69 	}

    70     }

    72     if (libFile == NULL) {

    73 	usage(programName);

    74 	return 1;

    75     }

    76     if ((bitOffset >= 8) || (bitOffset < 0)) {

    77 	usage(programName);

    78 	return 1;

    79     }

    81     /* open the target signature file */

    82     fd = PR_OpenFile(libFile,PR_RDWR,0666);

    83     if (fd == NULL ) {

    84 	/* lperror(libFile); */

    85 	PR_fprintf(pr_stderr,"Couldn't Open %s\n",libFile);

    86 	goto loser;

    87     }

    89     if (offset < 0) { /* convert to positive offset */

    90 	pos = PR_Seek(fd, offset, PR_SEEK_END);

    91 	if (pos == -1) {

    92 	    PR_fprintf(pr_stderr,"Seek for read on %s (to %d) failed\n",

    93 		       libFile, offset);

    94 	    goto loser;

    95 	}

    96 	offset = pos;

    97     }

    99     /* read the byte */

   100     pos = PR_Seek(fd, offset, PR_SEEK_SET);

   101     if (pos != offset) {

   102 	PR_fprintf(pr_stderr,"Seek for read on %s (to %d) failed\n",

   103 	           libFile, offset);

   104 	goto loser;

   105     }

   106     bytesRead = PR_Read(fd, &cbuf, 1);

   107     if (bytesRead != 1) {

   108 	PR_fprintf(pr_stderr,"Read on %s (to %d) failed\n", libFile, offset);

   109 	goto loser;

   110     }

   112     PR_fprintf(pr_stderr,"Changing byte 0x%08x (%d): from %02x (%d) to ",

   113 		offset, offset, (unsigned char)cbuf, (unsigned char)cbuf);

   114     /* change it */

   115     cbuf ^= 1 << bitOffset;

   116     PR_fprintf(pr_stderr,"%02x (%d)\n",

   117                (unsigned char)cbuf, (unsigned char)cbuf);

   119     /* write it back out */

   120     pos = PR_Seek(fd, offset, PR_SEEK_SET);

   121     if (pos != offset) {

   122 	PR_fprintf(pr_stderr,"Seek for write on %s (to %d) failed\n",

   123 	           libFile, offset);

   124 	goto loser;

   125     }

   126     bytesWritten = PR_Write(fd, &cbuf, 1);

   127     if (bytesWritten != 1) {

   128 	PR_fprintf(pr_stderr,"Write on %s (to %d) failed\n", libFile, offset);

   129 	goto loser;

   130     }

   132     retval = 0;

   134 loser:

   135     if (fd)

   136 	PR_Close(fd);

   137     PR_Cleanup ();

   138     return retval;

   139 }

   141 /*#DEFINES += -DSHLIB_SUFFIX=\"$(DLL_SUFFIX)\" -DSHLIB_PREFIX=\"$(DLL_PREFIX)\" */

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