Fix memory leak when rejecting bogus DH parameters.

tglsfdc · tglsfdc · commit e835e89a0fd2 · 2021-03-20T12:47:21.000-04:00
While back-patching e0e569e, I noted that there were some other places where we ought to be applying DH_free(); namely, where we load some DH parameters from a file and then reject them as not being sufficiently secure. While it seems really unlikely that anybody would hit these code paths in production, let alone do so repeatedly, let's fix it for consistency. Back-patch to v10 where this code was introduced. Discussion: https://postgr.es/m/16160-18367e56e9a28264@postgresql.org
diff --git a/src/backend/libpq/be-secure-openssl.c b/src/backend/libpq/be-secure-openssl.c
@@ -922,13 +922,15 @@ load_dh_file(char *filename, bool isServerStart)
 				(errcode(ERRCODE_CONFIG_FILE_ERROR),
 				 errmsg("invalid DH parameters: %s",
 						SSLerrmessage(ERR_get_error()))));
+		DH_free(dh);
 		return NULL;
 	}
 	if (codes & DH_CHECK_P_NOT_PRIME)
 	{
 		ereport(isServerStart ? FATAL : LOG,
 				(errcode(ERRCODE_CONFIG_FILE_ERROR),
 				 errmsg("invalid DH parameters: p is not prime")));
+		DH_free(dh);
 		return NULL;
 	}
 	if ((codes & DH_NOT_SUITABLE_GENERATOR) &&
@@ -937,6 +939,7 @@ load_dh_file(char *filename, bool isServerStart)
 		ereport(isServerStart ? FATAL : LOG,
 				(errcode(ERRCODE_CONFIG_FILE_ERROR),
 				 errmsg("invalid DH parameters: neither suitable generator or safe prime")));
+		DH_free(dh);
 		return NULL;
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -922,13 +922,15 @@ load_dh_file(char *filename, bool isServerStart)`
`922`	`922`	`(errcode(ERRCODE_CONFIG_FILE_ERROR),`
`923`	`923`	`errmsg("invalid DH parameters: %s",`
`924`	`924`	`SSLerrmessage(ERR_get_error()))));`
	`925`	`+ DH_free(dh);`
`925`	`926`	`return NULL;`
`926`	`927`	`}`
`927`	`928`	`if (codes & DH_CHECK_P_NOT_PRIME)`
`928`	`929`	`{`
`929`	`930`	`ereport(isServerStart ? FATAL : LOG,`
`930`	`931`	`(errcode(ERRCODE_CONFIG_FILE_ERROR),`
`931`	`932`	`errmsg("invalid DH parameters: p is not prime")));`
	`933`	`+ DH_free(dh);`
`932`	`934`	`return NULL;`
`933`	`935`	`}`
`934`	`936`	`if ((codes & DH_NOT_SUITABLE_GENERATOR) &&`
`@@ -937,6 +939,7 @@ load_dh_file(char *filename, bool isServerStart)`
`937`	`939`	`ereport(isServerStart ? FATAL : LOG,`
`938`	`940`	`(errcode(ERRCODE_CONFIG_FILE_ERROR),`
`939`	`941`	`errmsg("invalid DH parameters: neither suitable generator or safe prime")));`
	`942`	`+ DH_free(dh);`
`940`	`943`	`return NULL;`
`941`	`944`	`}`
`942`	`945`