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Overview
Comment:Stronger CSRF token based on a SHA1 hash of the login cookie.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | csrf-defense-enhancement
Files: files | file ages | folders
SHA3-256: ff3746c4c214a50e74328463604d9ae1c5aa82576d308a64c18c32f7fa130442
User & Date: drh 2023-09-18 14:13:38.976
Context
2023-09-18
14:29
Cleanup forms on the skin editor page. ... (check-in: 5feae3fd75 user: drh tags: csrf-defense-enhancement)
14:13
Stronger CSRF token based on a SHA1 hash of the login cookie. ... (check-in: ff3746c4c2 user: drh tags: csrf-defense-enhancement)
13:18
Try to simplify and rationalize the defenses against cross-site request forgery attacks. A hodgepodge of techniques have been used in the past. This changes attempts to make everything work more alike and to centralize CSRF defenses for easier auditing. ... (check-in: 88a402fe2a user: drh tags: csrf-defense-enhancement)
Changes
Unified Diff Ignore Whitespace Patch
Changes to src/builtin.c.
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    CX("};\n"/* fossil.config */);
    CX("window.fossil.user = {");
    CX("name: %!j,", (g.zLogin&&*g.zLogin) ? g.zLogin : "guest");
    CX("isAdmin: %s", (g.perm.Admin || g.perm.Setup) ? "true" : "false");
    CX("};\n"/*fossil.user*/);
    CX("if(fossil.config.skin.isDark) "
       "document.body.classList.add('fossil-dark-style');\n");
#if 0
    /* Is it safe to emit the CSRF token here? Some pages add it
    ** as a hidden form field. */
    if(g.zCsrfToken[0]!=0){
      CX("window.fossil.csrfToken = %!j;\n",
         g.zCsrfToken);
    }
#endif
    /*
    ** fossil.page holds info about the current page. This is also
    ** where the current page "should" store any of its own
    ** page-specific state, and it is reserved for that purpose.
    */
    CX("window.fossil.page = {"
       "name:\"%T\""







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    CX("};\n"/* fossil.config */);
    CX("window.fossil.user = {");
    CX("name: %!j,", (g.zLogin&&*g.zLogin) ? g.zLogin : "guest");
    CX("isAdmin: %s", (g.perm.Admin || g.perm.Setup) ? "true" : "false");
    CX("};\n"/*fossil.user*/);
    CX("if(fossil.config.skin.isDark) "
       "document.body.classList.add('fossil-dark-style');\n");








    /*
    ** fossil.page holds info about the current page. This is also
    ** where the current page "should" store any of its own
    ** page-specific state, and it is reserved for that purpose.
    */
    CX("window.fossil.page = {"
       "name:\"%T\""
Changes to src/login.c.
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#  include <windows.h>           /* for Sleep */
#  if defined(__MINGW32__) || defined(_MSC_VER)
#    define sleep Sleep            /* windows does not have sleep, but Sleep */
#  endif
#endif
#include <time.h>

















/*
** Return the login-group name.  Or return 0 if this repository is
** not a member of a login-group.
*/
const char *login_group_name(void){
  static const char *zGroup = 0;







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#  include <windows.h>           /* for Sleep */
#  if defined(__MINGW32__) || defined(_MSC_VER)
#    define sleep Sleep            /* windows does not have sleep, but Sleep */
#  endif
#endif
#include <time.h>

/*
** Compute an appropriate Anti-CSRF token into g.zCsrfToken[].
*/
static void login_create_csrf_secret(const char *zSeed){
  unsigned char zResult[20];
  int i;

  sha1sum_binary(zSeed, zResult);
  for(i=0; i<sizeof(g.zCsrfToken)-1; i++){
    g.zCsrfToken[i] = "abcdefghijklmnopqrstuvwxyz"
                      "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                      "0123456789-/"[zResult[i]%64];
  }
  g.zCsrfToken[i] = 0;
}

/*
** Return the login-group name.  Or return 0 if this repository is
** not a member of a login-group.
*/
const char *login_group_name(void){
  static const char *zGroup = 0;
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  zIpAddr = PD("REMOTE_ADDR","nil");
  if( ( cgi_is_loopback(zIpAddr)
       || (g.fSshClient & CGI_SSH_CLIENT)!=0 )
   && g.useLocalauth
   && db_get_int("localauth",0)==0
   && P("HTTPS")==0
  ){

    if( g.localOpen ) zLogin = db_lget("default-user",0);
    if( zLogin!=0 ){
      uid = db_int(0, "SELECT uid FROM user WHERE login=%Q", zLogin);
    }else{
      uid = db_int(0, "SELECT uid FROM user WHERE cap LIKE '%%s%%'");
    }
    g.zLogin = db_text("?", "SELECT login FROM user WHERE uid=%d", uid);
    zCap = "sxy";
    g.noPswd = 1;
    g.isHuman = 1;
    sqlite3_snprintf(sizeof(g.zCsrfToken), g.zCsrfToken, "localhost");



  }

  /* Check the login cookie to see if it matches a known valid user.
  */
  if( uid==0 && (zCookie = P(login_cookie_name()))!=0 ){
    /* Parse the cookie value up into HASH/ARG/USER */
    char *zHash = fossil_strdup(zCookie);







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  zIpAddr = PD("REMOTE_ADDR","nil");
  if( ( cgi_is_loopback(zIpAddr)
       || (g.fSshClient & CGI_SSH_CLIENT)!=0 )
   && g.useLocalauth
   && db_get_int("localauth",0)==0
   && P("HTTPS")==0
  ){
    char *zSeed;
    if( g.localOpen ) zLogin = db_lget("default-user",0);
    if( zLogin!=0 ){
      uid = db_int(0, "SELECT uid FROM user WHERE login=%Q", zLogin);
    }else{
      uid = db_int(0, "SELECT uid FROM user WHERE cap LIKE '%%s%%'");
    }
    g.zLogin = db_text("?", "SELECT login FROM user WHERE uid=%d", uid);
    zCap = "sxy";
    g.noPswd = 1;
    g.isHuman = 1;
    zSeed = db_text("??", "SELECT uid||quote(login)||quote(pw)||quote(cookie)"
                          "  FROM user WHERE uid=%d", uid);
    login_create_csrf_secret(zSeed);
    fossil_free(zSeed);
  }

  /* Check the login cookie to see if it matches a known valid user.
  */
  if( uid==0 && (zCookie = P(login_cookie_name()))!=0 ){
    /* Parse the cookie value up into HASH/ARG/USER */
    char *zHash = fossil_strdup(zCookie);
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      */
      uid = login_find_user(zUser, zHash);
      if( uid==0 && login_transfer_credentials(zUser,zArg,zHash) ){
        uid = login_find_user(zUser, zHash);
        if( uid ) record_login_attempt(zUser, zIpAddr, 1);
      }
    }
    sqlite3_snprintf(sizeof(g.zCsrfToken), g.zCsrfToken, "%.10s", zHash);
  }

  /* If no user found and the REMOTE_USER environment variable is set,
  ** then accept the value of REMOTE_USER as the user.
  */
  if( uid==0 ){
    const char *zRemoteUser = P("REMOTE_USER");







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      */
      uid = login_find_user(zUser, zHash);
      if( uid==0 && login_transfer_credentials(zUser,zArg,zHash) ){
        uid = login_find_user(zUser, zHash);
        if( uid ) record_login_attempt(zUser, zIpAddr, 1);
      }
    }
    login_create_csrf_secret(zHash);
  }

  /* If no user found and the REMOTE_USER environment variable is set,
  ** then accept the value of REMOTE_USER as the user.
  */
  if( uid==0 ){
    const char *zRemoteUser = P("REMOTE_USER");
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  if( uid==0 ){
    uid = db_int(0, "SELECT uid FROM user WHERE login='nobody'");
    if( uid==0 ){
      /* If there is no user "nobody", then make one up - with no privileges */
      uid = -1;
      zCap = "";
    }
    sqlite3_snprintf(sizeof(g.zCsrfToken), g.zCsrfToken, "none");
  }

  login_set_uid(uid, zCap);
}

/*
** Set the current logged in user to be uid.  zCap is precomputed







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  if( uid==0 ){
    uid = db_int(0, "SELECT uid FROM user WHERE login='nobody'");
    if( uid==0 ){
      /* If there is no user "nobody", then make one up - with no privileges */
      uid = -1;
      zCap = "";
    }
    login_create_csrf_secret("none");
  }

  login_set_uid(uid, zCap);
}

/*
** Set the current logged in user to be uid.  zCap is precomputed
Changes to src/main.c.
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#ifdef FOSSIL_ENABLE_TCL
  /* all Tcl related context necessary for integration */
  struct TclContext tcl;
#endif

  /* For defense against Cross-site Request Forgery attacks */
  char zCsrfToken[12];    /* Value of the anti-CSRF token */
  int okCsrf;             /* -1:  unsafe
                          **  0:  unknown
                          **  1:  same origin
                          **  2:  same origin + is POST
                          **  3:  same origin, POST, valid csrf token */

  int parseCnt[10];       /* Counts of artifacts parsed */







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#ifdef FOSSIL_ENABLE_TCL
  /* all Tcl related context necessary for integration */
  struct TclContext tcl;
#endif

  /* For defense against Cross-site Request Forgery attacks */
  char zCsrfToken[16];    /* Value of the anti-CSRF token */
  int okCsrf;             /* -1:  unsafe
                          **  0:  unknown
                          **  1:  same origin
                          **  2:  same origin + is POST
                          **  3:  same origin, POST, valid csrf token */

  int parseCnt[10];       /* Counts of artifacts parsed */
Changes to src/sha1.c.
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    blob_zero(pCksum);
  }
  blob_resize(pCksum, 40);
  SHA1Final(zResult, &ctx);
  DigestToBase16(zResult, blob_buffer(pCksum));
  return 0;
}














/*
** Compute the SHA1 checksum of a zero-terminated string.  The
** result is held in memory obtained from mprintf().
*/
char *sha1sum(const char *zIn){
  SHA1Context ctx;







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    blob_zero(pCksum);
  }
  blob_resize(pCksum, 40);
  SHA1Final(zResult, &ctx);
  DigestToBase16(zResult, blob_buffer(pCksum));
  return 0;
}

/*
** Compute a binary SHA1 checksum of a zero-terminated string.  The
** result is stored in zOut, which is a buffer that must be at least
** 20 bytes in size.
*/
void sha1sum_binary(const char *zIn, unsigned char *zOut){
  SHA1Context ctx;

  SHA1Init(&ctx);
  SHA1Update(&ctx, (unsigned const char*)zIn, strlen(zIn));
  SHA1Final(zOut, &ctx);
}

/*
** Compute the SHA1 checksum of a zero-terminated string.  The
** result is held in memory obtained from mprintf().
*/
char *sha1sum(const char *zIn){
  SHA1Context ctx;