pgcrypto: fix memset() calls that might be optimized away

Specifically, on-stack memset() might be removed, so:

	* Replace memset() with px_memset()
	* Add px_memset to copy_crlf()
	* Add px_memset to pgp-s2k.c

Patch by Marko Kreen

Report by PVS-Studio

Backpatch through 8.4.

1 files changed, 10 insertions, 9 deletions

diff --git a/contrib/pgcrypto/pgp-decrypt.c b/contrib/pgcrypto/pgp-decrypt.c
index c9aa6cd66aa..2063e8c319e 100644
--- a/contrib/pgcrypto/pgp-decrypt.c
+++ b/contrib/pgcrypto/pgp-decrypt.c
@@ -210,7 +210,7 @@ pktreader_free(void *priv)
 {
 	struct PktData *pkt = priv;
 
-	memset(pkt, 0, sizeof(*pkt));
+	px_memset(pkt, 0, sizeof(*pkt));
 	px_free(pkt);
 }
 
@@ -257,7 +257,7 @@ prefix_init(void **priv_p, void *arg, PullFilter *src)
 	if (res != len + 2)
 	{
 		px_debug("prefix_init: short read");
-		memset(tmpbuf, 0, sizeof(tmpbuf));
+		px_memset(tmpbuf, 0, sizeof(tmpbuf));
 		return PXE_PGP_CORRUPT_DATA;
 	}
 
@@ -280,7 +280,7 @@ prefix_init(void **priv_p, void *arg, PullFilter *src)
 		 */
 		ctx->corrupt_prefix = 1;
 	}
-	memset(tmpbuf, 0, sizeof(tmpbuf));
+	px_memset(tmpbuf, 0, sizeof(tmpbuf));
 	return 0;
 }
 
@@ -395,8 +395,8 @@ mdc_finish(PGP_Context *ctx, PullFilter *src,
 	 */
 	px_md_finish(ctx->mdc_ctx, hash);
 	res = memcmp(hash, *data_p, 20);
-	memset(hash, 0, 20);
-	memset(tmpbuf, 0, sizeof(tmpbuf));
+	px_memset(hash, 0, 20);
+	px_memset(tmpbuf, 0, sizeof(tmpbuf));
 	if (res != 0)
 	{
 		px_debug("mdc_finish: mdc failed");
@@ -493,7 +493,7 @@ mdcbuf_finish(struct MDCBufData * st)
 	px_md_update(st->ctx->mdc_ctx, st->mdc_buf, 2);
 	px_md_finish(st->ctx->mdc_ctx, hash);
 	res = memcmp(hash, st->mdc_buf + 2, 20);
-	memset(hash, 0, 20);
+	px_memset(hash, 0, 20);
 	if (res)
 	{
 		px_debug("mdcbuf_finish: MDC does not match");
@@ -593,7 +593,7 @@ mdcbuf_free(void *priv)
 
 	px_md_free(st->ctx->mdc_ctx);
 	st->ctx->mdc_ctx = NULL;
-	memset(st, 0, sizeof(*st));
+	px_memset(st, 0, sizeof(*st));
 	px_free(st);
 }
 
@@ -703,7 +703,7 @@ parse_symenc_sesskey(PGP_Context *ctx, PullFilter *src)
 		res = decrypt_key(ctx, p, res);
 	}
 
-	memset(tmpbuf, 0, sizeof(tmpbuf));
+	px_memset(tmpbuf, 0, sizeof(tmpbuf));
 	return res;
 }
 
@@ -753,6 +753,7 @@ copy_crlf(MBuf *dst, uint8 *data, int len, int *got_cr)
 		if (res < 0)
 			return res;
 	}
+	px_memset(tmpbuf, 0, sizeof(tmpbuf));
 	return 0;
 }
 
@@ -792,7 +793,7 @@ parse_literal_data(PGP_Context *ctx, MBuf *dst, PullFilter *pkt)
 		px_debug("parse_literal_data: unexpected eof");
 		return PXE_PGP_CORRUPT_DATA;
 	}
-	memset(tmpbuf, 0, 4);
+	px_memset(tmpbuf, 0, 4);
 
 	/* check if text */
 	if (ctx->text_mode)