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Change SHA2 implementation based on OpenSSL to use EVP digest routines 

The use of low-level hash routines is not recommended by upstream
OpenSSL since 2000, and pgcrypto already switched to EVP as of 5ff4a67.
This takes advantage of the refactoring done in 87ae969 that has
introduced the allocation and free routines for cryptographic hashes.

Since 1.1.0, OpenSSL does not publish the contents of the cryptohash
contexts, forcing any consumers to rely on OpenSSL for all allocations.
Hence, the resource owner callback mechanism gains a new set of routines
to track and free cryptohash contexts when using OpenSSL, preventing any
risks of leaks in the backend.  Nothing is needed in the frontend thanks
to the refactoring of 87ae969, and the resowner knowledge is isolated
into cryptohash_openssl.c.

Note that this also fixes a failure with SCRAM authentication when using
FIPS in OpenSSL, but as there have been few complaints about this
problem and as this causes an ABI breakage, no backpatch is done.

Author: Michael Paquier
Reviewed-by: Daniel Gustafsson, Heikki Linnakangas
Discussion: https://postgr.es/m/20200924025314.GE7405@paquier.xyz
Discussion: https://postgr.es/m/20180911030250.GA27115@paquier.xyz
This commit is contained in:
Michael Paquier 2020-12-04 10:49:23 +09:00
parent 3f8971d92e
commit 4f48a6fbe2
5 changed files with 160 additions and 52 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/backend/replication/basebackup.c
View File

@ -729,11 +729,17 @@ perform_base_backup(basebackup_options *opt)
errmsg("checksum verification failure during base backup")));
}
/*
* Make sure to free the manifest before the resource owners as manifests
* use cryptohash contexts that may depend on resource owners (like
* OpenSSL).
*/
FreeBackupManifest(&manifest);
/* clean up the resource owner we created */
WalSndResourceCleanup(true);
pgstat_progress_end_command();
FreeBackupManifest(&manifest);
}
/*

62
src/backend/utils/resowner/resowner.c
View File

@ -20,6 +20,7 @@
*/
#include "postgres.h"
#include "common/cryptohash.h"
#include "common/hashfn.h"
#include "jit/jit.h"
#include "storage/bufmgr.h"
@ -128,6 +129,7 @@ typedef struct ResourceOwnerData
ResourceArray filearr; /* open temporary files */
ResourceArray dsmarr; /* dynamic shmem segments */
ResourceArray jitarr; /* JIT contexts */
ResourceArray cryptohasharr; /* cryptohash contexts */
/* We can remember up to MAX_RESOWNER_LOCKS references to local locks. */
int nlocks; /* number of owned locks */
@ -175,6 +177,7 @@ static void PrintTupleDescLeakWarning(TupleDesc tupdesc);
static void PrintSnapshotLeakWarning(Snapshot snapshot);
static void PrintFileLeakWarning(File file);
static void PrintDSMLeakWarning(dsm_segment *seg);
static void PrintCryptoHashLeakWarning(Datum handle);
/*****************************************************************************
@ -444,6 +447,7 @@ ResourceOwnerCreate(ResourceOwner parent, const char *name)
ResourceArrayInit(&(owner->filearr), FileGetDatum(-1));
ResourceArrayInit(&(owner->dsmarr), PointerGetDatum(NULL));
ResourceArrayInit(&(owner->jitarr), PointerGetDatum(NULL));
ResourceArrayInit(&(owner->cryptohasharr), PointerGetDatum(NULL));
return owner;
}
@ -553,6 +557,17 @@ ResourceOwnerReleaseInternal(ResourceOwner owner,
jit_release_context(context);
}
/* Ditto for cryptohash contexts */
while (ResourceArrayGetAny(&(owner->cryptohasharr), &foundres))
{
pg_cryptohash_ctx *context =
(pg_cryptohash_ctx *) PointerGetDatum(foundres);
if (isCommit)
PrintCryptoHashLeakWarning(foundres);
pg_cryptohash_free(context);
}
}
else if (phase == RESOURCE_RELEASE_LOCKS)
{
@ -725,6 +740,7 @@ ResourceOwnerDelete(ResourceOwner owner)
Assert(owner->filearr.nitems == 0);
Assert(owner->dsmarr.nitems == 0);
Assert(owner->jitarr.nitems == 0);
Assert(owner->cryptohasharr.nitems == 0);
Assert(owner->nlocks == 0 || owner->nlocks == MAX_RESOWNER_LOCKS + 1);
/*
@ -752,6 +768,7 @@ ResourceOwnerDelete(ResourceOwner owner)
ResourceArrayFree(&(owner->filearr));
ResourceArrayFree(&(owner->dsmarr));
ResourceArrayFree(&(owner->jitarr));
ResourceArrayFree(&(owner->cryptohasharr));
pfree(owner);
}
@ -1370,3 +1387,48 @@ ResourceOwnerForgetJIT(ResourceOwner owner, Datum handle)
elog(ERROR, "JIT context %p is not owned by resource owner %s",
DatumGetPointer(handle), owner->name);
}
/*
* Make sure there is room for at least one more entry in a ResourceOwner's
* cryptohash context reference array.
*
* This is separate from actually inserting an entry because if we run out of
* memory, it's critical to do so *before* acquiring the resource.
*/
void
ResourceOwnerEnlargeCryptoHash(ResourceOwner owner)
{
ResourceArrayEnlarge(&(owner->cryptohasharr));
}
/*
* Remember that a cryptohash context is owned by a ResourceOwner
*
* Caller must have previously done ResourceOwnerEnlargeCryptoHash()
*/
void
ResourceOwnerRememberCryptoHash(ResourceOwner owner, Datum handle)
{
ResourceArrayAdd(&(owner->cryptohasharr), handle);
}
/*
* Forget that a cryptohash context is owned by a ResourceOwner
*/
void
ResourceOwnerForgetCryptoHash(ResourceOwner owner, Datum handle)
{
if (!ResourceArrayRemove(&(owner->cryptohasharr), handle))
elog(ERROR, "cryptohash context %p is not owned by resource owner %s",
DatumGetPointer(handle), owner->name);
}
/*
* Debugging subroutine
*/
static void
PrintCryptoHashLeakWarning(Datum handle)
{
elog(WARNING, "cryptohash context reference leak: context %p still referenced",
DatumGetPointer(handle));
}

134
src/common/cryptohash_openssl.c
View File

@ -21,9 +21,14 @@
#include "postgres_fe.h"
#endif
#include <openssl/sha.h>
#include <openssl/evp.h>
#include "common/cryptohash.h"
#ifndef FRONTEND
#include "utils/memutils.h"
#include "utils/resowner.h"
#include "utils/resowner_private.h"
#endif
/*
* In backend, use palloc/pfree to ease the error handling. In frontend,
@ -37,6 +42,21 @@
#define FREE(ptr) free(ptr)
#endif
/*
* Internal structure for pg_cryptohash_ctx->data.
*
* This tracks the resource owner associated to each EVP context data
* for the backend.
*/
typedef struct pg_cryptohash_state
{
EVP_MD_CTX *evpctx;
#ifndef FRONTEND
ResourceOwner resowner;
#endif
} pg_cryptohash_state;
/*
* pg_cryptohash_create
*
@ -47,32 +67,53 @@ pg_cryptohash_ctx *
pg_cryptohash_create(pg_cryptohash_type type)
{
pg_cryptohash_ctx *ctx;
pg_cryptohash_state *state;
ctx = ALLOC(sizeof(pg_cryptohash_ctx));
if (ctx == NULL)
return NULL;
ctx->type = type;
switch (type)
{
case PG_SHA224:
case PG_SHA256:
ctx->data = ALLOC(sizeof(SHA256_CTX));
break;
case PG_SHA384:
case PG_SHA512:
ctx->data = ALLOC(sizeof(SHA512_CTX));
break;
}
if (ctx->data == NULL)
state = ALLOC(sizeof(pg_cryptohash_state));
if (state == NULL)
{
explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
FREE(ctx);
return NULL;
}
ctx->data = state;
ctx->type = type;
#ifndef FRONTEND
ResourceOwnerEnlargeCryptoHash(CurrentResourceOwner);
#endif
/*
* Initialization takes care of assigning the correct type for OpenSSL.
*/
state->evpctx = EVP_MD_CTX_create();
if (state->evpctx == NULL)
{
explicit_bzero(state, sizeof(pg_cryptohash_state));
explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
#ifndef FRONTEND
ereport(ERROR,
(errcode(ERRCODE_OUT_OF_MEMORY),
errmsg("out of memory")));
#else
FREE(state);
FREE(ctx);
return NULL;
#endif
}
#ifndef FRONTEND
state->resowner = CurrentResourceOwner;
ResourceOwnerRememberCryptoHash(CurrentResourceOwner,
PointerGetDatum(ctx));
#endif
return ctx;
}
@ -85,23 +126,26 @@ int
pg_cryptohash_init(pg_cryptohash_ctx *ctx)
{
int status = 0;
pg_cryptohash_state *state;
if (ctx == NULL)
return 0;
state = (pg_cryptohash_state *) ctx->data;
switch (ctx->type)
{
case PG_SHA224:
status = SHA224_Init((SHA256_CTX *) ctx->data);
status = EVP_DigestInit_ex(state->evpctx, EVP_sha224(), NULL);
break;
case PG_SHA256:
status = SHA256_Init((SHA256_CTX *) ctx->data);
status = EVP_DigestInit_ex(state->evpctx, EVP_sha256(), NULL);
break;
case PG_SHA384:
status = SHA384_Init((SHA512_CTX *) ctx->data);
status = EVP_DigestInit_ex(state->evpctx, EVP_sha384(), NULL);
break;
case PG_SHA512:
status = SHA512_Init((SHA512_CTX *) ctx->data);
status = EVP_DigestInit_ex(state->evpctx, EVP_sha512(), NULL);
break;
}
@ -120,25 +164,13 @@ int
pg_cryptohash_update(pg_cryptohash_ctx *ctx, const uint8 *data, size_t len)
{
int status = 0;
pg_cryptohash_state *state;
if (ctx == NULL)
return 0;
switch (ctx->type)
{
case PG_SHA224:
status = SHA224_Update((SHA256_CTX *) ctx->data, data, len);
break;
case PG_SHA256:
status = SHA256_Update((SHA256_CTX *) ctx->data, data, len);
break;
case PG_SHA384:
status = SHA384_Update((SHA512_CTX *) ctx->data, data, len);
break;
case PG_SHA512:
status = SHA512_Update((SHA512_CTX *) ctx->data, data, len);
break;
}
state = (pg_cryptohash_state *) ctx->data;
status = EVP_DigestUpdate(state->evpctx, data, len);
/* OpenSSL internals return 1 on success, 0 on failure */
if (status <= 0)
@ -155,25 +187,13 @@ int
pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest)
{
int status = 0;
pg_cryptohash_state *state;
if (ctx == NULL)
return 0;
switch (ctx->type)
{
case PG_SHA224:
status = SHA224_Final(dest, (SHA256_CTX *) ctx->data);
break;
case PG_SHA256:
status = SHA256_Final(dest, (SHA256_CTX *) ctx->data);
break;
case PG_SHA384:
status = SHA384_Final(dest, (SHA512_CTX *) ctx->data);
break;
case PG_SHA512:
status = SHA512_Final(dest, (SHA512_CTX *) ctx->data);
break;
}
state = (pg_cryptohash_state *) ctx->data;
status = EVP_DigestFinal_ex(state->evpctx, dest, 0);
/* OpenSSL internals return 1 on success, 0 on failure */
if (status <= 0)
@ -189,9 +209,21 @@ pg_cryptohash_final(pg_cryptohash_ctx *ctx, uint8 *dest)
void
pg_cryptohash_free(pg_cryptohash_ctx *ctx)
{
pg_cryptohash_state *state;
if (ctx == NULL)
return;
FREE(ctx->data);
state = (pg_cryptohash_state *) ctx->data;
EVP_MD_CTX_destroy(state->evpctx);
#ifndef FRONTEND
ResourceOwnerForgetCryptoHash(state->resowner,
PointerGetDatum(ctx));
#endif
explicit_bzero(state, sizeof(pg_cryptohash_state));
explicit_bzero(ctx, sizeof(pg_cryptohash_ctx));
FREE(state);
FREE(ctx);
}

7
src/include/utils/resowner_private.h
View File

@ -95,4 +95,11 @@ extern void ResourceOwnerRememberJIT(ResourceOwner owner,
extern void ResourceOwnerForgetJIT(ResourceOwner owner,
Datum handle);
/* support for cryptohash context management */
extern void ResourceOwnerEnlargeCryptoHash(ResourceOwner owner);
extern void ResourceOwnerRememberCryptoHash(ResourceOwner owner,
Datum handle);
extern void ResourceOwnerForgetCryptoHash(ResourceOwner owner,
Datum handle);
#endif /* RESOWNER_PRIVATE_H */

1
src/tools/pgindent/typedefs.list
View File

@ -3180,6 +3180,7 @@ pg_conv_map
pg_crc32
pg_crc32c
pg_cryptohash_ctx
pg_cryptohash_state
pg_cryptohash_type
pg_ctype_cache
pg_enc