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Commit ce9b75d

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author
Neil Conway
committed
Patch from Marko Kreen:
pgcrypto crypt()/md5 and hmac() leak memory when compiled against OpenSSL as openssl.c digest ->reset will do two DigestInit calls against a context. This happened to work with OpenSSL 0.9.6 but not with 0.9.7+. Reason for the messy code was that I tried to avoid creating wrapper structure to transport algorithm info and tried to use OpenSSL context for it. The fix is to create wrapper structure. It also uses newer digest API to avoid memory allocations on reset with newer OpenSSLs. Thanks to Daniel Blaisdell for reporting it.
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‎contrib/pgcrypto/openssl.c‎

Lines changed: 70 additions & 32 deletions
Original file line numberDiff line numberDiff line change
@@ -26,7 +26,7 @@
2626
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
2727
* SUCH DAMAGE.
2828
*
29-
* $PostgreSQL: pgsql/contrib/pgcrypto/openssl.c,v 1.26 2005/10/15 02:49:06 momjian Exp $
29+
* $PostgreSQL: pgsql/contrib/pgcrypto/openssl.c,v 1.27 2006/02/18 20:48:51 neilc Exp $
3030
*/
3131

3232
#include "postgres.h"
@@ -47,17 +47,24 @@
4747
#define MAX_IV (128/8)
4848

4949
/*
50-
* Does OpenSSL support AES?
50+
* Compatibility with OpenSSL 0.9.6
51+
*
52+
* It needs AES and newer DES and digest API.
5153
*/
5254
#if OPENSSL_VERSION_NUMBER >= 0x00907000L
5355

54-
/* Yes, it does. */
56+
/*
57+
* Nothing needed for OpenSSL 0.9.7+
58+
*/
59+
5560
#include <openssl/aes.h>
61+
5662
#else /* old OPENSSL */
5763

5864
/*
59-
* No, it does not. So use included rijndael code to emulate it.
65+
* Emulate OpenSSL AES.
6066
*/
67+
6168
#include "rijndael.c"
6269

6370
#define AES_ENCRYPT 1
@@ -90,12 +97,11 @@
9097
memcpy(iv, (src) + (len) - 16, 16); \
9198
} \
9299
} while (0)
93-
#endif /* old OPENSSL */
94100

95101
/*
96-
* Compatibility with older OpenSSL API for DES.
102+
* Emulate DES_* API
97103
*/
98-
#if OPENSSL_VERSION_NUMBER < 0x00907000L
104+
99105
#define DES_key_schedule des_key_schedule
100106
#define DES_cblock des_cblock
101107
#define DES_set_key(k, ks) \
@@ -110,63 +116,91 @@
110116
#define DES_ede3_cbc_encrypt(i, o, l, k1, k2, k3, iv, e) \
111117
des_ede3_cbc_encrypt((i), (o), \
112118
(l), *(k1), *(k2), *(k3), (iv), (e))
113-
#endif
119+
120+
/*
121+
* Emulate newer digest API.
122+
*/
123+
124+
static void EVP_MD_CTX_init(EVP_MD_CTX *ctx)
125+
{
126+
memset(ctx, 0, sizeof(*ctx));
127+
}
128+
129+
static int EVP_MD_CTX_cleanup(EVP_MD_CTX *ctx)
130+
{
131+
memset(ctx, 0, sizeof(*ctx));
132+
return 1;
133+
}
134+
135+
static int EVP_DigestInit_ex(EVP_MD_CTX *ctx, const EVP_MD *md, void *engine)
136+
{
137+
EVP_DigestInit(ctx, md);
138+
return 1;
139+
}
140+
141+
static int EVP_DigestFinal_ex(EVP_MD_CTX *ctx, unsigned char *res, unsigned int *len)
142+
{
143+
EVP_DigestFinal(ctx, res, len);
144+
return 1;
145+
}
146+
147+
#endif /* old OpenSSL */
114148

115149
/*
116150
* Hashes
117151
*/
152+
153+
typedef struct OSSLDigest {
154+
const EVP_MD *algo;
155+
EVP_MD_CTX ctx;
156+
} OSSLDigest;
157+
118158
static unsigned
119159
digest_result_size(PX_MD * h)
120160
{
121-
return EVP_MD_CTX_size((EVP_MD_CTX *) h->p.ptr);
161+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
162+
return EVP_MD_CTX_size(&digest->ctx);
122163
}
123164

124165
static unsigned
125166
digest_block_size(PX_MD * h)
126167
{
127-
return EVP_MD_CTX_block_size((EVP_MD_CTX *) h->p.ptr);
168+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
169+
return EVP_MD_CTX_block_size(&digest->ctx);
128170
}
129171

130172
static void
131173
digest_reset(PX_MD * h)
132174
{
133-
EVP_MD_CTX *ctx = (EVP_MD_CTX *) h->p.ptr;
134-
const EVP_MD *md;
175+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
135176

136-
md = EVP_MD_CTX_md(ctx);
137-
138-
EVP_DigestInit(ctx, md);
177+
EVP_DigestInit_ex(&digest->ctx, digest->algo, NULL);
139178
}
140179

141180
static void
142181
digest_update(PX_MD * h, const uint8 *data, unsigned dlen)
143182
{
144-
EVP_MD_CTX *ctx = (EVP_MD_CTX *) h->p.ptr;
183+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
145184

146-
EVP_DigestUpdate(ctx, data, dlen);
185+
EVP_DigestUpdate(&digest->ctx, data, dlen);
147186
}
148187

149188
static void
150189
digest_finish(PX_MD * h, uint8 *dst)
151190
{
152-
EVP_MD_CTX *ctx = (EVP_MD_CTX *) h->p.ptr;
153-
const EVP_MD *md = EVP_MD_CTX_md(ctx);
154-
155-
EVP_DigestFinal(ctx, dst, NULL);
191+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
156192

157-
/*
158-
* Some builds of 0.9.7x clear all of ctx in EVP_DigestFinal. Fix it by
159-
* reinitializing ctx.
160-
*/
161-
EVP_DigestInit(ctx, md);
193+
EVP_DigestFinal_ex(&digest->ctx, dst, NULL);
162194
}
163195

164196
static void
165197
digest_free(PX_MD * h)
166198
{
167-
EVP_MD_CTX *ctx = (EVP_MD_CTX *) h->p.ptr;
199+
OSSLDigest *digest = (OSSLDigest *)h->p.ptr;
200+
201+
EVP_MD_CTX_cleanup(&digest->ctx);
168202

169-
px_free(ctx);
203+
px_free(digest);
170204
px_free(h);
171205
}
172206

@@ -178,8 +212,8 @@ int
178212
px_find_digest(const char *name, PX_MD ** res)
179213
{
180214
const EVP_MD *md;
181-
EVP_MD_CTX *ctx;
182215
PX_MD *h;
216+
OSSLDigest *digest;
183217

184218
if (!px_openssl_initialized)
185219
{
@@ -191,8 +225,12 @@ px_find_digest(const char *name, PX_MD ** res)
191225
if (md == NULL)
192226
return PXE_NO_HASH;
193227

194-
ctx = px_alloc(sizeof(*ctx));
195-
EVP_DigestInit(ctx, md);
228+
digest = px_alloc(sizeof(*digest));
229+
digest->algo = md;
230+
231+
EVP_MD_CTX_init(&digest->ctx);
232+
if (EVP_DigestInit_ex(&digest->ctx, digest->algo, NULL) == 0)
233+
return -1;
196234

197235
h = px_alloc(sizeof(*h));
198236
h->result_size = digest_result_size;
@@ -201,7 +239,7 @@ px_find_digest(const char *name, PX_MD ** res)
201239
h->update = digest_update;
202240
h->finish = digest_finish;
203241
h->free = digest_free;
204-
h->p.ptr = (void *) ctx;
242+
h->p.ptr = (void *) digest;
205243

206244
*res = h;
207245
return 0;

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