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/*
** 2020-04-20
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
******************************************************************************
**
** This file implements a VFS shim that obfuscates database content
** written to disk by applying a CipherStrategy.
**
** COMPILING
**
** This extension requires SQLite 3.32.0 or later.
**
**
** LOADING
**
** Initialize it using a single API call as follows:
**
** sqlite3_obfsvfs_init();
**
** Obfsvfs is a VFS Shim. When loaded, "obfsvfs" becomes the new
** default VFS and it uses the prior default VFS as the next VFS
** down in the stack. This is normally what you want. However, it
** complex situations where multiple VFS shims are being loaded,
** it might be important to ensure that obfsvfs is loaded in the
** correct order so that it sequences itself into the default VFS
** Shim stack in the right order.
**
** USING
**
** Open database connections using the sqlite3_open_v2() with
** the SQLITE_OPEN_URI flag and using a URI filename that includes
** the query parameter "key=XXXXXXXXXXX..." where the XXXX... consists
** of 64 hexadecimal digits (32 bytes of content).
**
** Create a new encrypted database by opening a file that does not
** yet exist using the key= query parameter.
**
** LIMITATIONS:
**
** * An obfuscated database must be created as such. There is
** no way to convert an existing database file into an
** obfuscated database file other than to run ".dump" on the
** older database and reimport the SQL text into a new
** obfuscated database.
**
** * There is no way to change the key value, other than to
** ".dump" and restore the database
**
** * The database page size must be exactly 8192 bytes. No other
** database page sizes are currently supported.
**
** * Memory-mapped I/O does not work for obfuscated databases.
** If you think about it, memory-mapped I/O doesn't make any
** sense for obfuscated databases since you have to make a
** copy of the content to deobfuscate anyhow - you might as
** well use normal read()/write().
**
** * Only the main database, the rollback journal, and WAL file
** are obfuscated. Other temporary files used for things like
** SAVEPOINTs or as part of a large external sort remain
** unobfuscated.
**
** * Requires SQLite 3.32.0 or later.
*/
#include "sqlite3.h"
#include <string.h>
#include <ctype.h>
#include <stdio.h> /* For debugging only */
#include "mozilla/dom/quota/IPCStreamCipherStrategy.h"
#include "mozilla/ScopeExit.h"
#include "nsPrintfCString.h"
/*
** Forward declaration of objects used by this utility
*/
using ObfsVfs = sqlite3_vfs;
/*
** Useful datatype abbreviations
*/
#if !defined(SQLITE_CORE)
using u8 = unsigned char;
#endif
/* Access to a lower-level VFS that (might) implement dynamic loading,
** access to randomness, etc.
*/
#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData))
#define ORIGFILE(p) ((sqlite3_file*)(((ObfsFile*)(p)) + 1))
/*
** Database page size for obfuscated databases
*/
#define OBFS_PGSZ 8192
using namespace mozilla;
using namespace mozilla::dom::quota;
/* An open file */
struct ObfsFile {
sqlite3_file base; /* IO methods */
const char* zFName; /* Original name of the file */
bool inCkpt; /* Currently doing a checkpoint */
ObfsFile* pPartner; /* Ptr from WAL to main-db, or from main-db to WAL */
void* pTemp; /* Temporary storage for encoded pages */
IPCStreamCipherStrategy*
encryptCipherStrategy; /* CipherStrategy for encryption */
IPCStreamCipherStrategy*
decryptCipherStrategy; /* CipherStrategy for decryption */
};
/*
** Methods for ObfsFile
*/
static int obfsClose(sqlite3_file*);
static int obfsRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
static int obfsWrite(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
static int obfsTruncate(sqlite3_file*, sqlite3_int64 size);
static int obfsSync(sqlite3_file*, int flags);
static int obfsFileSize(sqlite3_file*, sqlite3_int64* pSize);
static int obfsLock(sqlite3_file*, int);
static int obfsUnlock(sqlite3_file*, int);
static int obfsCheckReservedLock(sqlite3_file*, int* pResOut);
static int obfsFileControl(sqlite3_file*, int op, void* pArg);
static int obfsSectorSize(sqlite3_file*);
static int obfsDeviceCharacteristics(sqlite3_file*);
static int obfsShmMap(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
static int obfsShmLock(sqlite3_file*, int offset, int n, int flags);
static void obfsShmBarrier(sqlite3_file*);
static int obfsShmUnmap(sqlite3_file*, int deleteFlag);
static int obfsFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void** pp);
static int obfsUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void* p);
/*
** Methods for ObfsVfs
*/
static int obfsOpen(sqlite3_vfs*, const char*, sqlite3_file*, int, int*);
static int obfsDelete(sqlite3_vfs*, const char* zPath, int syncDir);
static int obfsAccess(sqlite3_vfs*, const char* zPath, int flags, int*);
static int obfsFullPathname(sqlite3_vfs*, const char* zPath, int, char* zOut);
static void* obfsDlOpen(sqlite3_vfs*, const char* zPath);
static void obfsDlError(sqlite3_vfs*, int nByte, char* zErrMsg);
static void (*obfsDlSym(sqlite3_vfs* pVfs, void* p, const char* zSym))(void);
static void obfsDlClose(sqlite3_vfs*, void*);
static int obfsRandomness(sqlite3_vfs*, int nByte, char* zBufOut);
static int obfsSleep(sqlite3_vfs*, int nMicroseconds);
static int obfsCurrentTime(sqlite3_vfs*, double*);
static int obfsGetLastError(sqlite3_vfs*, int, char*);
static int obfsCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
static int obfsSetSystemCall(sqlite3_vfs*, const char*, sqlite3_syscall_ptr);
static sqlite3_syscall_ptr obfsGetSystemCall(sqlite3_vfs*, const char* z);
static const char* obfsNextSystemCall(sqlite3_vfs*, const char* zName);
static const sqlite3_io_methods obfs_io_methods = {
3, /* iVersion */
obfsClose, /* xClose */
obfsRead, /* xRead */
obfsWrite, /* xWrite */
obfsTruncate, /* xTruncate */
obfsSync, /* xSync */
obfsFileSize, /* xFileSize */
obfsLock, /* xLock */
obfsUnlock, /* xUnlock */
obfsCheckReservedLock, /* xCheckReservedLock */
obfsFileControl, /* xFileControl */
obfsSectorSize, /* xSectorSize */
obfsDeviceCharacteristics, /* xDeviceCharacteristics */
obfsShmMap, /* xShmMap */
obfsShmLock, /* xShmLock */
obfsShmBarrier, /* xShmBarrier */
obfsShmUnmap, /* xShmUnmap */
obfsFetch, /* xFetch */
obfsUnfetch /* xUnfetch */
};
static constexpr int kKeyBytes = 32;
static constexpr int kIvBytes = IPCStreamCipherStrategy::BlockPrefixLength;
static constexpr int kClearTextPrefixBytesOnFirstPage = 32;
static constexpr int kReservedBytes = 32;
static constexpr int kBasicBlockSize = IPCStreamCipherStrategy::BasicBlockSize;
static_assert(kClearTextPrefixBytesOnFirstPage % kBasicBlockSize == 0);
static_assert(kReservedBytes % kBasicBlockSize == 0);
/* Obfuscate a page using p->encryptCipherStrategy.
**
** A new random nonce is created and stored in the last 32 bytes
** of the page. All other bytes of the page are obfuscasted using the
** CipherStrategy. Except, for page-1 (including the SQLite
** database header) the first 32 bytes are not obfuscated
**
** Return a pointer to the obfuscated content, which is held in the
** p->pTemp buffer. Or return a NULL pointer if something goes wrong.
** Errors are reported using NS_WARNING().
*/
static void* obfsEncode(ObfsFile* p, /* File containing page to be obfuscated */
u8* a, /* database page to be obfuscated */
int nByte /* Bytes of content in a[]. Must be a multiple
of kBasicBlockSize. */
) {
u8 aIv[kIvBytes];
u8* pOut;
int i;
static_assert((kIvBytes & (kIvBytes - 1)) == 0);
sqlite3_randomness(kIvBytes, aIv);
pOut = (u8*)p->pTemp;
if (pOut == nullptr) {
pOut = static_cast<u8*>(sqlite3_malloc64(nByte));
if (pOut == nullptr) {
NS_WARNING(nsPrintfCString("unable to allocate a buffer in which to"
" write obfuscated database content for %s",
p->zFName)
.get());
return nullptr;
}
p->pTemp = pOut;
}
if (memcmp(a, "SQLite format 3", 16) == 0) {
i = kClearTextPrefixBytesOnFirstPage;
if (a[20] != kReservedBytes) {
NS_WARNING(nsPrintfCString("obfuscated database must have reserved-bytes"
" set to %d",
kReservedBytes)
.get());
return nullptr;
}
memcpy(pOut, a, kClearTextPrefixBytesOnFirstPage);
} else {
i = 0;
}
const int payloadLength = nByte - kReservedBytes - i;
MOZ_ASSERT(payloadLength > 0);
// XXX I guess this can be done in-place as well, then we don't need the
// temporary page at all, I guess?
p->encryptCipherStrategy->Cipher(
Span{aIv}, Span{a + i, static_cast<unsigned>(payloadLength)},
Span{pOut + i, static_cast<unsigned>(payloadLength)});
memcpy(pOut + nByte - kReservedBytes, aIv, kIvBytes);
return pOut;
}
/* De-obfuscate a page using p->decryptCipherStrategy.
**
** The deobfuscation is done in-place.
**
** For pages that begin with the SQLite header text, the first
** 32 bytes are not deobfuscated.
*/
static void obfsDecode(ObfsFile* p, /* File containing page to be obfuscated */
u8* a, /* database page to be obfuscated */
int nByte /* Bytes of content in a[]. Must be a multiple
of kBasicBlockSize. */
) {
int i;
if (memcmp(a, "SQLite format 3", 16) == 0) {
i = kClearTextPrefixBytesOnFirstPage;
} else {
i = 0;
}
const int payloadLength = nByte - kReservedBytes - i;
MOZ_ASSERT(payloadLength > 0);
p->decryptCipherStrategy->Cipher(
Span{a + nByte - kReservedBytes, kIvBytes},
Span{a + i, static_cast<unsigned>(payloadLength)},
Span{a + i, static_cast<unsigned>(payloadLength)});
}
/*
** Close an obfsucated file.
*/
static int obfsClose(sqlite3_file* pFile) {
ObfsFile* p = (ObfsFile*)pFile;
if (p->pPartner) {
MOZ_ASSERT(p->pPartner->pPartner == p);
p->pPartner->pPartner = nullptr;
p->pPartner = nullptr;
}
sqlite3_free(p->pTemp);
delete p->decryptCipherStrategy;
delete p->encryptCipherStrategy;
pFile = ORIGFILE(pFile);
return pFile->pMethods->xClose(pFile);
}
/*
** Read data from an obfuscated file.
**
** If the file is less than one full page in length, then return
** a substitute "prototype" page-1. This prototype page one
** specifies a database in WAL mode with an 8192-byte page size
** and a 32-byte reserved-bytes value. Those settings are necessary
** for obfuscation to function correctly.
*/
static int obfsRead(sqlite3_file* pFile, void* zBuf, int iAmt,
sqlite_int64 iOfst) {
int rc;
ObfsFile* p = (ObfsFile*)pFile;
pFile = ORIGFILE(pFile);
rc = pFile->pMethods->xRead(pFile, zBuf, iAmt, iOfst);
if (rc == SQLITE_OK) {
if (iAmt == OBFS_PGSZ && !p->inCkpt) {
obfsDecode(p, (u8*)zBuf, iAmt);
}
} else if (SQLITE_IOERR_SHORT_READ && iOfst == 0 && iAmt >= 100) {
static const unsigned char aEmptyDb[] = {
0x53, 0x51, 0x4c, 0x69, 0x74, 0x65, 0x20, 0x66,
0x6f, 0x72, 0x6d, 0x61, 0x74, 0x20, 0x33, 0x00,
0x20, 0x00, 0x02, 0x02, kReservedBytes, 0x40, 0x20, 0x20,
0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01};
memcpy(zBuf, aEmptyDb, sizeof(aEmptyDb));
memset(((u8*)zBuf) + sizeof(aEmptyDb), 0, iAmt - sizeof(aEmptyDb));
rc = SQLITE_OK;
}
return rc;
}
/*
** Write data to an obfuscated file or journal.
*/
static int obfsWrite(sqlite3_file* pFile, const void* zBuf, int iAmt,
sqlite_int64 iOfst) {
ObfsFile* p = (ObfsFile*)pFile;
pFile = ORIGFILE(pFile);
if (iAmt == OBFS_PGSZ && !p->inCkpt) {
zBuf = obfsEncode(p, (u8*)zBuf, iAmt);
if (zBuf == nullptr) {
return SQLITE_IOERR;
}
}
return pFile->pMethods->xWrite(pFile, zBuf, iAmt, iOfst);
}
/*
** Truncate an obfuscated file.
*/
static int obfsTruncate(sqlite3_file* pFile, sqlite_int64 size) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xTruncate(pFile, size);
}
/*
** Sync an obfuscated file.
*/
static int obfsSync(sqlite3_file* pFile, int flags) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xSync(pFile, flags);
}
/*
** Return the current file-size of an obfuscated file.
*/
static int obfsFileSize(sqlite3_file* pFile, sqlite_int64* pSize) {
ObfsFile* p = (ObfsFile*)pFile;
pFile = ORIGFILE(p);
return pFile->pMethods->xFileSize(pFile, pSize);
}
/*
** Lock an obfuscated file.
*/
static int obfsLock(sqlite3_file* pFile, int eLock) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xLock(pFile, eLock);
}
/*
** Unlock an obfuscated file.
*/
static int obfsUnlock(sqlite3_file* pFile, int eLock) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xUnlock(pFile, eLock);
}
/*
** Check if another file-handle holds a RESERVED lock on an obfuscated file.
*/
static int obfsCheckReservedLock(sqlite3_file* pFile, int* pResOut) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xCheckReservedLock(pFile, pResOut);
}
/*
** File control method. For custom operations on an obfuscated file.
*/
static int obfsFileControl(sqlite3_file* pFile, int op, void* pArg) {
int rc;
ObfsFile* p = (ObfsFile*)pFile;
pFile = ORIGFILE(pFile);
if (op == SQLITE_FCNTL_PRAGMA) {
char** azArg = (char**)pArg;
MOZ_ASSERT(azArg[1] != nullptr);
if (azArg[2] != nullptr && sqlite3_stricmp(azArg[1], "page_size") == 0) {
/* Do not allow page size changes on an obfuscated database */
return SQLITE_OK;
}
} else if (op == SQLITE_FCNTL_CKPT_START || op == SQLITE_FCNTL_CKPT_DONE) {
p->inCkpt = op == SQLITE_FCNTL_CKPT_START;
if (p->pPartner) {
p->pPartner->inCkpt = p->inCkpt;
}
}
rc = pFile->pMethods->xFileControl(pFile, op, pArg);
if (rc == SQLITE_OK && op == SQLITE_FCNTL_VFSNAME) {
*(char**)pArg = sqlite3_mprintf("obfs/%z", *(char**)pArg);
}
return rc;
}
/*
** Return the sector-size in bytes for an obfuscated file.
*/
static int obfsSectorSize(sqlite3_file* pFile) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xSectorSize(pFile);
}
/*
** Return the device characteristic flags supported by an obfuscated file.
*/
static int obfsDeviceCharacteristics(sqlite3_file* pFile) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xDeviceCharacteristics(pFile);
}
/* Create a shared memory file mapping */
static int obfsShmMap(sqlite3_file* pFile, int iPg, int pgsz, int bExtend,
void volatile** pp) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xShmMap(pFile, iPg, pgsz, bExtend, pp);
}
/* Perform locking on a shared-memory segment */
static int obfsShmLock(sqlite3_file* pFile, int offset, int n, int flags) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xShmLock(pFile, offset, n, flags);
}
/* Memory barrier operation on shared memory */
static void obfsShmBarrier(sqlite3_file* pFile) {
pFile = ORIGFILE(pFile);
pFile->pMethods->xShmBarrier(pFile);
}
/* Unmap a shared memory segment */
static int obfsShmUnmap(sqlite3_file* pFile, int deleteFlag) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xShmUnmap(pFile, deleteFlag);
}
/* Fetch a page of a memory-mapped file */
static int obfsFetch(sqlite3_file* pFile, sqlite3_int64 iOfst, int iAmt,
void** pp) {
*pp = nullptr;
return SQLITE_OK;
}
/* Release a memory-mapped page */
static int obfsUnfetch(sqlite3_file* pFile, sqlite3_int64 iOfst, void* pPage) {
pFile = ORIGFILE(pFile);
return pFile->pMethods->xUnfetch(pFile, iOfst, pPage);
}
/*
** Translate a single byte of Hex into an integer.
** This routine only works if h really is a valid hexadecimal
** character: 0..9a..fA..F
*/
static u8 obfsHexToInt(int h) {
MOZ_ASSERT((h >= '0' && h <= '9') || (h >= 'a' && h <= 'f') ||
(h >= 'A' && h <= 'F'));
#if 1 /* ASCII */
h += 9 * (1 & (h >> 6));
#else /* EBCDIC */
h += 9 * (1 & ~(h >> 4));
#endif
return (u8)(h & 0xf);
}
/*
** Open a new file.
**
** If the file is an ordinary database file, or a rollback or WAL journal
** file, and if the key=XXXX parameter exists, then try to open the file
** as an obfuscated database. All other open attempts fall through into
** the lower-level VFS shim.
**
** If the key=XXXX parameter exists but is not 64-bytes of hex key, then
** put an error message in NS_WARNING() and return SQLITE_CANTOPEN.
*/
static int obfsOpen(sqlite3_vfs* pVfs, const char* zName, sqlite3_file* pFile,
int flags, int* pOutFlags) {
ObfsFile* p;
sqlite3_file* pSubFile;
sqlite3_vfs* pSubVfs;
int rc, i;
const char* zKey;
u8 aKey[kKeyBytes];
pSubVfs = ORIGVFS(pVfs);
if (flags &
(SQLITE_OPEN_MAIN_DB | SQLITE_OPEN_WAL | SQLITE_OPEN_MAIN_JOURNAL)) {
zKey = sqlite3_uri_parameter(zName, "key");
} else {
zKey = nullptr;
}
if (zKey == nullptr) {
return pSubVfs->xOpen(pSubVfs, zName, pFile, flags, pOutFlags);
}
for (i = 0;
i < kKeyBytes && isxdigit(zKey[i * 2]) && isxdigit(zKey[i * 2 + 1]);
i++) {
aKey[i] = (obfsHexToInt(zKey[i * 2]) << 4) | obfsHexToInt(zKey[i * 2 + 1]);
}
if (i != kKeyBytes) {
NS_WARNING(
nsPrintfCString("invalid query parameter on %s: key=%s", zName, zKey)
.get());
return SQLITE_CANTOPEN;
}
p = (ObfsFile*)pFile;
memset(p, 0, sizeof(*p));
auto encryptCipherStrategy = MakeUnique<IPCStreamCipherStrategy>();
auto decryptCipherStrategy = MakeUnique<IPCStreamCipherStrategy>();
auto resetMethods = MakeScopeExit([pFile] { pFile->pMethods = nullptr; });
if (NS_WARN_IF(NS_FAILED(encryptCipherStrategy->Init(
CipherMode::Encrypt, Span{aKey, sizeof(aKey)},
IPCStreamCipherStrategy::MakeBlockPrefix())))) {
return SQLITE_ERROR;
}
if (NS_WARN_IF(NS_FAILED(decryptCipherStrategy->Init(
CipherMode::Decrypt, Span{aKey, sizeof(aKey)})))) {
return SQLITE_ERROR;
}
pSubFile = ORIGFILE(pFile);
p->base.pMethods = &obfs_io_methods;
rc = pSubVfs->xOpen(pSubVfs, zName, pSubFile, flags, pOutFlags);
if (rc) {
return rc;
}
resetMethods.release();
if (flags & (SQLITE_OPEN_WAL | SQLITE_OPEN_MAIN_JOURNAL)) {
sqlite3_file* pDb = sqlite3_database_file_object(zName);
p->pPartner = (ObfsFile*)pDb;
MOZ_ASSERT(p->pPartner->pPartner == nullptr);
p->pPartner->pPartner = p;
}
p->zFName = zName;
p->encryptCipherStrategy = encryptCipherStrategy.release();
p->decryptCipherStrategy = decryptCipherStrategy.release();
return SQLITE_OK;
}
/*
** All other VFS methods are pass-thrus.
*/
static int obfsDelete(sqlite3_vfs* pVfs, const char* zPath, int syncDir) {
return ORIGVFS(pVfs)->xDelete(ORIGVFS(pVfs), zPath, syncDir);
}
static int obfsAccess(sqlite3_vfs* pVfs, const char* zPath, int flags,
int* pResOut) {
return ORIGVFS(pVfs)->xAccess(ORIGVFS(pVfs), zPath, flags, pResOut);
}
static int obfsFullPathname(sqlite3_vfs* pVfs, const char* zPath, int nOut,
char* zOut) {
return ORIGVFS(pVfs)->xFullPathname(ORIGVFS(pVfs), zPath, nOut, zOut);
}
static void* obfsDlOpen(sqlite3_vfs* pVfs, const char* zPath) {
return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath);
}
static void obfsDlError(sqlite3_vfs* pVfs, int nByte, char* zErrMsg) {
ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg);
}
static void (*obfsDlSym(sqlite3_vfs* pVfs, void* p, const char* zSym))(void) {
return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym);
}
static void obfsDlClose(sqlite3_vfs* pVfs, void* pHandle) {
ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle);
}
static int obfsRandomness(sqlite3_vfs* pVfs, int nByte, char* zBufOut) {
return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut);
}
static int obfsSleep(sqlite3_vfs* pVfs, int nMicroseconds) {
return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicroseconds);
}
static int obfsCurrentTime(sqlite3_vfs* pVfs, double* pTimeOut) {
return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut);
}
static int obfsGetLastError(sqlite3_vfs* pVfs, int a, char* b) {
return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b);
}
static int obfsCurrentTimeInt64(sqlite3_vfs* pVfs, sqlite3_int64* p) {
return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p);
}
static int obfsSetSystemCall(sqlite3_vfs* pVfs, const char* zName,
sqlite3_syscall_ptr pCall) {
return ORIGVFS(pVfs)->xSetSystemCall(ORIGVFS(pVfs), zName, pCall);
}
static sqlite3_syscall_ptr obfsGetSystemCall(sqlite3_vfs* pVfs,
const char* zName) {
return ORIGVFS(pVfs)->xGetSystemCall(ORIGVFS(pVfs), zName);
}
static const char* obfsNextSystemCall(sqlite3_vfs* pVfs, const char* zName) {
return ORIGVFS(pVfs)->xNextSystemCall(ORIGVFS(pVfs), zName);
}
namespace mozilla {
namespace storage {
const char* GetObfuscatingVFSName() { return "obfsvfs"; }
UniquePtr<sqlite3_vfs> ConstructObfuscatingVFS(const char* aBaseVFSName) {
MOZ_ASSERT(aBaseVFSName);
if (sqlite3_vfs_find(GetObfuscatingVFSName()) != nullptr) {
return nullptr;
}
sqlite3_vfs* const pOrig = sqlite3_vfs_find(aBaseVFSName);
if (pOrig == nullptr) {
return nullptr;
}
#ifdef DEBUG
// If the VFS version is higher than the last known one, you should update
// this VFS adding appropriate methods for any methods added in the version
// change.
static constexpr int kLastKnownVfsVersion = 3;
MOZ_ASSERT(pOrig->iVersion <= kLastKnownVfsVersion);
#endif
const sqlite3_vfs obfs_vfs = {
pOrig->iVersion, /* iVersion */
static_cast<int>(pOrig->szOsFile + sizeof(ObfsFile)), /* szOsFile */
1024, /* mxPathname */
nullptr, /* pNext */
GetObfuscatingVFSName(), /* zName */
pOrig, /* pAppData */
obfsOpen, /* xOpen */
obfsDelete, /* xDelete */
obfsAccess, /* xAccess */
obfsFullPathname, /* xFullPathname */
obfsDlOpen, /* xDlOpen */
obfsDlError, /* xDlError */
obfsDlSym, /* xDlSym */
obfsDlClose, /* xDlClose */
obfsRandomness, /* xRandomness */
obfsSleep, /* xSleep */
obfsCurrentTime, /* xCurrentTime */
obfsGetLastError, /* xGetLastError */
obfsCurrentTimeInt64, /* xCurrentTimeInt64 */
obfsSetSystemCall, /* xSetSystemCall */
obfsGetSystemCall, /* xGetSystemCall */
obfsNextSystemCall /* xNextSystemCall */
};
return MakeUnique<sqlite3_vfs>(obfs_vfs);
}
} // namespace storage
} // namespace mozilla