The Tor Browser: security/nss/lib/softoken/legacydb/dbmshim.c@b8a032363ba2 (annotated)

security/nss/lib/softoken/legacydb/dbmshim.c@b8a032363ba2 (annotated)

security/nss/lib/softoken/legacydb/dbmshim.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * Berkeley DB 1.85 Shim code to handle blobs.
  */
 #include "mcom_db.h"
 #include "secitem.h"
 #include "nssb64.h"
 #include "blapi.h"
 #include "secerr.h"
 #include "lgdb.h"
 /*
  *   Blob block:
  *   Byte 0   CERTDB Version           -+                       -+
  *   Byte 1   certDBEntryTypeBlob       |  BLOB_HEAD_LEN         |
  *   Byte 2   flags (always '0');       |                        |
  *   Byte 3   reserved (always '0');   -+                        |
  *   Byte 4   LSB length                | <--BLOB_LENGTH_START   | BLOB_BUF_LEN
  *   Byte 5       .                     |                        |
  *   Byte 6       .                     | BLOB_LENGTH_LEN        |
  *   Byte 7   MSB length                |                        |
  *   Byte 8   blob_filename   -+       -+  <-- BLOB_NAME_START   |
  *   Byte 9       .            | BLOB_NAME_LEN                   |
  *     .          .            |                                 |
  *   Byte 37      .           -+                                -+
  */
 #define DBS_BLOCK_SIZE (16*1024) /* 16 k */
 #define DBS_MAX_ENTRY_SIZE (DBS_BLOCK_SIZE - (2048)) /* 14 k */
 #define DBS_CACHE_SIZE	DBS_BLOCK_SIZE*8
 #define ROUNDDIV(x,y) (x+(y-1))/y
 #define BLOB_HEAD_LEN 4
 #define BLOB_LENGTH_START BLOB_HEAD_LEN
 #define BLOB_LENGTH_LEN 4
 #define BLOB_NAME_START BLOB_LENGTH_START+BLOB_LENGTH_LEN
 #define BLOB_NAME_LEN 1+ROUNDDIV(SHA1_LENGTH,3)*4+1
 #define BLOB_BUF_LEN BLOB_HEAD_LEN+BLOB_LENGTH_LEN+BLOB_NAME_LEN
 /* a Shim data structure. This data structure has a db built into it. */
 typedef struct DBSStr DBS;
 struct DBSStr {
     DB db;
     char *blobdir;
     int mode;
     PRBool readOnly;
     PRFileMap *dbs_mapfile;
     unsigned char *dbs_addr;
     PRUint32 dbs_len;
     char staticBlobArea[BLOB_BUF_LEN];
 };
 /*
  * return true if the Datablock contains a blobtype
  */
 static PRBool
 dbs_IsBlob(DBT *blobData)
 {
     unsigned char *addr = (unsigned char *)blobData->data;
     if (blobData->size < BLOB_BUF_LEN) {
 	return PR_FALSE;
     }
     return addr && ((certDBEntryType) addr[1] == certDBEntryTypeBlob);
 }
 /*
  * extract the filename in the blob of the real data set.
  * This value is not malloced (does not need to be freed by the caller.
  */
 static const char *
 dbs_getBlobFileName(DBT *blobData)
 {
     char *addr = (char *)blobData->data;
     return &addr[BLOB_NAME_START];
 }
 /*
  * extract the size of the actual blob from the blob record
  */
 static PRUint32
 dbs_getBlobSize(DBT *blobData)
 {
     unsigned char *addr = (unsigned char *)blobData->data;
     return (PRUint32)(addr[BLOB_LENGTH_START+3] << 24) |
 			(addr[BLOB_LENGTH_START+2] << 16) |
 			(addr[BLOB_LENGTH_START+1] << 8) |
 			addr[BLOB_LENGTH_START];
 }
 /* We are using base64 data for the filename, but base64 data can include a
  * '/' which is interpreted as a path separator on  many platforms. Replace it
  * with an inocuous '-'. We don't need to convert back because we never actual
  * decode the filename.
  */
 static void
 dbs_replaceSlash(char *cp, int len)
 {
    while (len--) {
 	if (*cp == '/') *cp = '-';
 	cp++;
    }
 }
 /*
  * create a blob record from a key, data and return it in blobData.
  * NOTE: The data element is static data (keeping with the dbm model).
  */
 static void
 dbs_mkBlob(DBS *dbsp,const DBT *key, const DBT *data, DBT *blobData)
 {
    unsigned char sha1_data[SHA1_LENGTH];
    char *b = dbsp->staticBlobArea;
    PRUint32 length = data->size;
    SECItem sha1Item;
    b[0] = CERT_DB_FILE_VERSION; /* certdb version number */
    b[1] = (char) certDBEntryTypeBlob; /* type */
    b[2] = 0; /* flags */
    b[3] = 0; /* reserved */
    b[BLOB_LENGTH_START] = length & 0xff;
    b[BLOB_LENGTH_START+1] = (length >> 8) & 0xff;
    b[BLOB_LENGTH_START+2] = (length >> 16) & 0xff;
    b[BLOB_LENGTH_START+3] = (length >> 24) & 0xff;
    sha1Item.data = sha1_data;
    sha1Item.len = SHA1_LENGTH;
    SHA1_HashBuf(sha1_data,key->data,key->size);
    b[BLOB_NAME_START]='b'; /* Make sure we start with a alpha */
    NSSBase64_EncodeItem(NULL,&b[BLOB_NAME_START+1],BLOB_NAME_LEN-1,&sha1Item);
    b[BLOB_BUF_LEN-1] = 0;
    dbs_replaceSlash(&b[BLOB_NAME_START+1],BLOB_NAME_LEN-1);
    blobData->data = b;
    blobData->size = BLOB_BUF_LEN;
    return;
 }
 /*
  * construct a path to the actual blob. The string returned must be
  * freed by the caller with PR_smprintf_free.
  *
  * Note: this file does lots of consistancy checks on the DBT. The
  * routines that call this depend on these checks, so they don't worry
  * about them (success of this routine implies a good blobdata record).
  */
 static char *
 dbs_getBlobFilePath(char *blobdir,DBT *blobData)
 {
     const char *name;
     if (blobdir == NULL) {
 	PR_SetError(SEC_ERROR_BAD_DATABASE,0);
 	return NULL;
     }
     if (!dbs_IsBlob(blobData)) {
 	PR_SetError(SEC_ERROR_BAD_DATABASE,0);
 	return NULL;
     }
     name = dbs_getBlobFileName(blobData);
     if (!name || *name == 0) {
 	PR_SetError(SEC_ERROR_BAD_DATABASE,0);
 	return NULL;
     }
     return  PR_smprintf("%s" PATH_SEPARATOR "%s", blobdir, name);
 }
 /*
  * Delete a blob file pointed to by the blob record.
  */
 static void
 dbs_removeBlob(DBS *dbsp, DBT *blobData)
 {
     char *file;
     file = dbs_getBlobFilePath(dbsp->blobdir, blobData);
     if (!file) {
 	return;
     }
     PR_Delete(file);
     PR_smprintf_free(file);
 }
 /*
  * Directory modes are slightly different, the 'x' bit needs to be on to
  * access them. Copy all the read bits to 'x' bits
  */
 static int
 dbs_DirMode(int mode)
 {
   int x_bits = (mode >> 2) &  0111;
   return mode | x_bits;
 }
 /*
  * write a data blob to it's file. blobdData is the blob record that will be
  * stored in the database. data is the actual data to go out on disk.
  */
 static int
 dbs_writeBlob(DBS *dbsp, int mode, DBT *blobData, const DBT *data)
 {
     char *file = NULL;
     PRFileDesc *filed;
     PRStatus status;
     int len;
     int error = 0;
     file = dbs_getBlobFilePath(dbsp->blobdir, blobData);
     if (!file) {
 	goto loser;
     }
     if (PR_Access(dbsp->blobdir, PR_ACCESS_EXISTS) != PR_SUCCESS) {
 	status = PR_MkDir(dbsp->blobdir,dbs_DirMode(mode));
 	if (status != PR_SUCCESS) {
 	    goto loser;
 	}
     }
     filed = PR_OpenFile(file,PR_CREATE_FILE|PR_TRUNCATE|PR_WRONLY, mode);
     if (filed == NULL) {
 	error = PR_GetError();
 	goto loser;
     }
     len = PR_Write(filed,data->data,data->size);
     error = PR_GetError();
     PR_Close(filed);
     if (len < (int)data->size) {
 	goto loser;
     }
     PR_smprintf_free(file);
     return 0;
 loser:
     if (file) {
 	PR_Delete(file);
 	PR_smprintf_free(file);
     }
     /* don't let close or delete reset the error */
     PR_SetError(error,0);
     return -1;
 }
 /*
  * we need to keep a address map in memory between calls to DBM.
  * remember what we have mapped can close it when we get another dbm
  * call.
  *
  * NOTE: Not all platforms support mapped files. This code is designed to
  * detect this at runtime. If map files aren't supported the OS will indicate
  * this by failing the PR_Memmap call. In this case we emulate mapped files
  * by just reading in the file into regular memory. We signal this state by
  * making dbs_mapfile NULL and dbs_addr non-NULL.
  */
 static void
 dbs_freemap(DBS *dbsp)
 {
     if (dbsp->dbs_mapfile) {
 	PR_MemUnmap(dbsp->dbs_addr,dbsp->dbs_len);
 	PR_CloseFileMap(dbsp->dbs_mapfile);
 	dbsp->dbs_mapfile = NULL;
 	dbsp->dbs_addr = NULL;
 	dbsp->dbs_len = 0;
     } else if (dbsp->dbs_addr) {
 	PORT_Free(dbsp->dbs_addr);
 	dbsp->dbs_addr = NULL;
 	dbsp->dbs_len = 0;
     }
     return;
 }
 static void
 dbs_setmap(DBS *dbsp, PRFileMap *mapfile, unsigned char *addr, PRUint32 len)
 {
     dbsp->dbs_mapfile = mapfile;
     dbsp->dbs_addr = addr;
     dbsp->dbs_len = len;
 }
 /*
  * platforms that cannot map the file need to read it into a temp buffer.
  */
 static unsigned char *
 dbs_EmulateMap(PRFileDesc *filed, int len)
 {
     unsigned char *addr;
     PRInt32 dataRead;
     addr = PORT_Alloc(len);
     if (addr == NULL) {
 	return NULL;
     }
     dataRead = PR_Read(filed,addr,len);
     if (dataRead != len) {
 	PORT_Free(addr);
 	if (dataRead > 0) {
 	    /* PR_Read didn't set an error, we need to */
 	    PR_SetError(SEC_ERROR_BAD_DATABASE,0);
 	}
 	return NULL;
     }
     return addr;
 }
 /*
  * pull a database record off the disk
  * data points to the blob record on input and the real record (if we could
  * read it) on output. if there is an error data is not modified.
  */
 static int
 dbs_readBlob(DBS *dbsp, DBT *data)
 {
     char *file = NULL;
     PRFileDesc *filed = NULL;
     PRFileMap *mapfile = NULL;
     unsigned char *addr = NULL;
     int error;
     int len = -1;
     file = dbs_getBlobFilePath(dbsp->blobdir, data);
     if (!file) {
 	goto loser;
     }
     filed = PR_OpenFile(file,PR_RDONLY,0);
     PR_smprintf_free(file); file = NULL;
     if (filed == NULL) {
 	goto loser;
     }
     len = dbs_getBlobSize(data);
     mapfile = PR_CreateFileMap(filed, len, PR_PROT_READONLY);
     if (mapfile == NULL) {
 	 /* USE PR_GetError instead of PORT_GetError here
 	  * because we are getting the error from PR_xxx
 	  * function */
 	if (PR_GetError() != PR_NOT_IMPLEMENTED_ERROR) {
 	    goto loser;
 	}
 	addr = dbs_EmulateMap(filed, len);
     } else {
 	addr = PR_MemMap(mapfile, 0, len);
     }
     if (addr == NULL) {
 	goto loser;
     }
     PR_Close(filed);
     dbs_setmap(dbsp,mapfile,addr,len);
     data->data = addr;
     data->size = len;
     return 0;
 loser:
     /* preserve the error code */
     error = PR_GetError();
     if (mapfile) {
 	PR_CloseFileMap(mapfile);
     }
     if (filed) {
 	PR_Close(filed);
     }
     PR_SetError(error,0);
     return -1;
 }
 /*
  * actual DBM shims
  */
 static int
 dbs_get(const DB *dbs, const DBT *key, DBT *data, unsigned int flags)
 {
     int ret;
     DBS *dbsp = (DBS *)dbs;
     DB *db = (DB *)dbs->internal;
     dbs_freemap(dbsp);
     ret = (* db->get)(db, key, data, flags);
     if ((ret == 0) && dbs_IsBlob(data)) {
 	ret = dbs_readBlob(dbsp,data);
     }
     return(ret);
 }
 static int
 dbs_put(const DB *dbs, DBT *key, const DBT *data, unsigned int flags)
 {
     DBT blob;
     int ret = 0;
     DBS *dbsp = (DBS *)dbs;
     DB *db = (DB *)dbs->internal;
     dbs_freemap(dbsp);
     /* If the db is readonly, just pass the data down to rdb and let it fail */
     if (!dbsp->readOnly) {
 	DBT oldData;
 	int ret1;
 	/* make sure the current record is deleted if it's a blob */
 	ret1 = (*db->get)(db,key,&oldData,0);
         if ((ret1 == 0) && flags == R_NOOVERWRITE) {
 	    /* let DBM return the error to maintain consistancy */
 	    return (* db->put)(db, key, data, flags);
 	}
 	if ((ret1 == 0) && dbs_IsBlob(&oldData)) {
 	    dbs_removeBlob(dbsp, &oldData);
 	}
 	if (data->size > DBS_MAX_ENTRY_SIZE) {
 	    dbs_mkBlob(dbsp,key,data,&blob);
 	    ret = dbs_writeBlob(dbsp, dbsp->mode, &blob, data);
 	    data = &blob;
 	}
     }
     if (ret == 0) {
 	ret = (* db->put)(db, key, data, flags);
     }
     return(ret);
 }
 static int
 dbs_sync(const DB *dbs, unsigned int flags)
 {
     DB *db = (DB *)dbs->internal;
     DBS *dbsp = (DBS *)dbs;
     dbs_freemap(dbsp);
     return (* db->sync)(db, flags);
 }
 static int
 dbs_del(const DB *dbs, const DBT *key, unsigned int flags)
 {
     int ret;
     DBS *dbsp = (DBS *)dbs;
     DB *db = (DB *)dbs->internal;
     dbs_freemap(dbsp);
     if (!dbsp->readOnly) {
 	DBT oldData;
 	ret = (*db->get)(db,key,&oldData,0);
 	if ((ret == 0) && dbs_IsBlob(&oldData)) {
 	    dbs_removeBlob(dbsp,&oldData);
 	}
     }
     return (* db->del)(db, key, flags);
 }
 static int
 dbs_seq(const DB *dbs, DBT *key, DBT *data, unsigned int flags)
 {
     int ret;
     DBS *dbsp = (DBS *)dbs;
     DB *db = (DB *)dbs->internal;
     dbs_freemap(dbsp);
     ret = (* db->seq)(db, key, data, flags);
     if ((ret == 0) && dbs_IsBlob(data)) {
 	/* don't return a blob read as an error so traversals keep going */
 	(void) dbs_readBlob(dbsp,data);
     }
     return(ret);
 }
 static int
 dbs_close(DB *dbs)
 {
     DBS *dbsp = (DBS *)dbs;
     DB *db = (DB *)dbs->internal;
     int ret;
     dbs_freemap(dbsp);
     ret = (* db->close)(db);
     PORT_Free(dbsp->blobdir);
     PORT_Free(dbsp);
     return ret;
 }
 static int
 dbs_fd(const DB *dbs)
 {
     DB *db = (DB *)dbs->internal;
     return (* db->fd)(db);
 }
 /*
  * the naming convention we use is
  * change the .xxx into .dir. (for nss it's always .db);
  * if no .extension exists or is equal to .dir, add a .dir
  * the returned data must be freed.
  */
 #define DIRSUFFIX ".dir"
 static char *
 dbs_mkBlobDirName(const char *dbname)
 {
     int dbname_len = PORT_Strlen(dbname);
     int dbname_end = dbname_len;
     const char *cp;
     char *blobDir = NULL;
     /* scan back from the end looking for either a directory separator, a '.',
      * or the end of the string. NOTE: Windows should check for both separators
      * here. For now this is safe because we know NSS always uses a '.'
      */
     for (cp = &dbname[dbname_len];
 		(cp > dbname) && (*cp != '.') && (*cp != *PATH_SEPARATOR) ;
 			cp--)
 	/* Empty */ ;
     if (*cp == '.') {
 	dbname_end = cp - dbname;
 	if (PORT_Strcmp(cp,DIRSUFFIX) == 0) {
 	    dbname_end = dbname_len;
 	}
     }
     blobDir = PORT_ZAlloc(dbname_end+sizeof(DIRSUFFIX));
     if (blobDir == NULL) {
 	return NULL;
     }
     PORT_Memcpy(blobDir,dbname,dbname_end);
     PORT_Memcpy(&blobDir[dbname_end],DIRSUFFIX,sizeof(DIRSUFFIX));
     return blobDir;
 }
 #define DBM_DEFAULT 0
 static const HASHINFO dbs_hashInfo = {
 	DBS_BLOCK_SIZE,		/* bucket size, must be greater than = to
 				 * or maximum entry size (+ header)
 				 * we allow before blobing */
 	DBM_DEFAULT,		/* Fill Factor */
 	DBM_DEFAULT,		/* number of elements */
 	DBS_CACHE_SIZE,		/* cache size */
 	DBM_DEFAULT,		/* hash function */
 	DBM_DEFAULT,		/* byte order */
 };
 /*
  * the open function. NOTE: this is the only exposed function in this file.
  * everything else is called through the function table pointer.
  */
 DB *
 dbsopen(const char *dbname, int flags, int mode, DBTYPE type,
 							 const void *userData)
 {
     DB *db = NULL,*dbs = NULL;
     DBS *dbsp = NULL;
     /* NOTE: we are overriding userData with dbs_hashInfo. since all known
      * callers pass 0, this is ok, otherwise we should merge the two */
     dbsp = (DBS *)PORT_ZAlloc(sizeof(DBS));
     if (!dbsp) {
 	return NULL;
     }
     dbs = &dbsp->db;
     dbsp->blobdir=dbs_mkBlobDirName(dbname);
     if (dbsp->blobdir == NULL) {
 	goto loser;
     }
     dbsp->mode = mode;
     dbsp->readOnly = (PRBool)(flags == NO_RDONLY);
     dbsp->dbs_mapfile = NULL;
     dbsp->dbs_addr = NULL;
     dbsp->dbs_len = 0;
     /* the real dbm call */
     db = dbopen(dbname, flags, mode, type, &dbs_hashInfo);
     if (db == NULL) {
 	goto loser;
     }
     dbs->internal = (void *) db;
     dbs->type = type;
     dbs->close = dbs_close;
     dbs->get = dbs_get;
     dbs->del = dbs_del;
     dbs->put = dbs_put;
     dbs->seq = dbs_seq;
     dbs->sync = dbs_sync;
     dbs->fd = dbs_fd;
     return dbs;
 loser:
     if (db) {
 	(*db->close)(db);
     }
     if (dbsp) {
 	if (dbsp->blobdir) {
 	    PORT_Free(dbsp->blobdir);
 	}
 	PORT_Free(dbsp);
     }
     return NULL;
 }

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security/nss/lib/softoken/legacydb/dbmshim.c@b8a032363ba2 (annotated)

security/nss/lib/softoken/legacydb/dbmshim.c