Revert "Fix corner case with PGP decompression in pgcrypto"

This reverts commit 9e10898, after finding out that buildfarm members
running SLES 15 on z390 complain on the compression and decompression
logic of the new test: pipistrelles, barbthroat and steamerduck.

Those hosts are visibly using hardware-specific changes to improve zlib
performance, requiring more investigation.

Thanks to Tom Lane for the discussion.

Discussion: https://postgr.es/m/20200722093749[email protected]
Backpatch-through: 9.5

diff --git a/contrib/pgcrypto/expected/pgp-compression.out b/contrib/pgcrypto/expected/pgp-compression.out
index d4c57feba30b84dc86c6a8287dbfef4c69fbf71e..32b350b8fe05b118b2271181f890cfbfabef23ea 100644 (file)
--- a/contrib/pgcrypto/expected/pgp-compression.out
+++ b/contrib/pgcrypto/expected/pgp-compression.out
@@ -48,33 +48,3 @@ select pgp_sym_decrypt(
  Secret message
 (1 row)
 
--- check corner case involving an input string of 16kB, as per bug #16476.
-SELECT setseed(0);
- setseed 
----------
- 
-(1 row)
-
-WITH random_string AS
-(
-  -- This generates a random string of 16366 bytes.  This is chosen
-  -- as random so that it does not get compressed, and the decompression
-  -- would work on a string with the same length as the origin, making the
-  -- test behavior more predictible.  lpad() ensures that the generated
-  -- hexadecimal value is completed by extra zero characters if random()
-  -- has generated a value strictly lower than 16.
-  SELECT string_agg(decode(lpad(to_hex((random()*256)::int), 2, '0'), 'hex'), '') as bytes
-    FROM generate_series(0, 16365)
-)
-SELECT bytes =
-    pgp_sym_decrypt_bytea(
-      pgp_sym_encrypt_bytea(bytes, 'key',
-                            'compress-algo=1,compress-level=1'),
-                            'key', 'expect-compress-algo=1')
-    AS is_same
-  FROM random_string;
- is_same 
----------
- t
-(1 row)
-

diff --git a/contrib/pgcrypto/pgp-compress.c b/contrib/pgcrypto/pgp-compress.c
index 141067708c5d50e2a1af8475660ed311a641dc03..eaeb221877f9119ffdbd5029bfb3883e46d7a4cb 100644 (file)
--- a/contrib/pgcrypto/pgp-compress.c
+++ b/contrib/pgcrypto/pgp-compress.c
@@ -244,17 +244,6 @@ decompress_read(void *priv, PullFilter *src, int len,
    struct DecomprData *dec = priv;
 
 restart:
-   if (dec->stream.avail_in == 0)
-   {
-       uint8      *tmp;
-
-       res = pullf_read(src, 8192, &tmp);
-       if (res < 0)
-           return res;
-       dec->stream.next_in = tmp;
-       dec->stream.avail_in = res;
-   }
-
    if (dec->buf_data > 0)
    {
        if (len > dec->buf_data)
@@ -268,6 +257,17 @@ restart:
    if (dec->eof)
        return 0;
 
+   if (dec->stream.avail_in == 0)
+   {
+       uint8      *tmp;
+
+       res = pullf_read(src, 8192, &tmp);
+       if (res < 0)
+           return res;
+       dec->stream.next_in = tmp;
+       dec->stream.avail_in = res;
+   }
+
    dec->stream.next_out = dec->buf;
    dec->stream.avail_out = dec->buf_len;
    dec->pos = dec->buf;

diff --git a/contrib/pgcrypto/sql/pgp-compression.sql b/contrib/pgcrypto/sql/pgp-compression.sql
index 87c59c6cabc4e7f380992c28625b12e662e1722b..ca9ee1fc0088a3416ff557853c8c26fda524f3c0 100644 (file)
--- a/contrib/pgcrypto/sql/pgp-compression.sql
+++ b/contrib/pgcrypto/sql/pgp-compression.sql
@@ -28,24 +28,3 @@ select pgp_sym_decrypt(
    pgp_sym_encrypt('Secret message', 'key',
            'compress-algo=2, compress-level=0'),
    'key', 'expect-compress-algo=0');
-
--- check corner case involving an input string of 16kB, as per bug #16476.
-SELECT setseed(0);
-WITH random_string AS
-(
-  -- This generates a random string of 16366 bytes.  This is chosen
-  -- as random so that it does not get compressed, and the decompression
-  -- would work on a string with the same length as the origin, making the
-  -- test behavior more predictible.  lpad() ensures that the generated
-  -- hexadecimal value is completed by extra zero characters if random()
-  -- has generated a value strictly lower than 16.
-  SELECT string_agg(decode(lpad(to_hex((random()*256)::int), 2, '0'), 'hex'), '') as bytes
-    FROM generate_series(0, 16365)
-)
-SELECT bytes =
-    pgp_sym_decrypt_bytea(
-      pgp_sym_encrypt_bytea(bytes, 'key',
-                            'compress-algo=1,compress-level=1'),
-                            'key', 'expect-compress-algo=1')
-    AS is_same
-  FROM random_string;