Get rid of another unconstify through API changes

This also makes the code in read_client_first_message() more similar
to read_client_final_message().

Reported-by: Mark Dilger <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/53a28052-f9f3-1808-fed9-460fd43035ab%402ndquadrant.com

diff --git a/src/backend/libpq/auth-scram.c b/src/backend/libpq/auth-scram.c
index bf97eecb42d7bb4329576fd9d468d5a6a87f7590..3cbe902ace1eb7ff97197f0327626c95dbd8603a 100644 (file)
--- a/src/backend/libpq/auth-scram.c
+++ b/src/backend/libpq/auth-scram.c
@@ -155,8 +155,8 @@ typedef struct
    char       *logdetail;
 } scram_state;
 
-static void read_client_first_message(scram_state *state, char *input);
-static void read_client_final_message(scram_state *state, char *input);
+static void read_client_first_message(scram_state *state, const char *input);
+static void read_client_final_message(scram_state *state, const char *input);
 static char *build_server_first_message(scram_state *state);
 static char *build_server_final_message(scram_state *state);
 static bool verify_client_proof(scram_state *state);
@@ -327,7 +327,7 @@ pg_be_scram_init(Port *port,
  * the client).
  */
 int
-pg_be_scram_exchange(void *opaq, char *input, int inputlen,
+pg_be_scram_exchange(void *opaq, const char *input, int inputlen,
                     char **output, int *outputlen, char **logdetail)
 {
    scram_state *state = (scram_state *) opaq;
@@ -811,11 +811,11 @@ read_any_attr(char **input, char *attr_p)
  * At this stage, any errors will be reported directly with ereport(ERROR).
  */
 static void
-read_client_first_message(scram_state *state, char *input)
+read_client_first_message(scram_state *state, const char *input)
 {
+   char       *p = pstrdup(input);
    char       *channel_binding_type;
 
-   input = pstrdup(input);
 
    /*------
     * The syntax for the client-first-message is: (RFC 5802)
@@ -881,8 +881,8 @@ read_client_first_message(scram_state *state, char *input)
     * Read gs2-cbind-flag.  (For details see also RFC 5802 Section 6 "Channel
     * Binding".)
     */
-   state->cbind_flag = *input;
-   switch (*input)
+   state->cbind_flag = *p;
+   switch (*p)
    {
        case 'n':
 
@@ -896,14 +896,14 @@ read_client_first_message(scram_state *state, char *input)
                         errmsg("malformed SCRAM message"),
                         errdetail("The client selected SCRAM-SHA-256-PLUS, but the SCRAM message does not include channel binding data.")));
 
-           input++;
-           if (*input != ',')
+           p++;
+           if (*p != ',')
                ereport(ERROR,
                        (errcode(ERRCODE_PROTOCOL_VIOLATION),
                         errmsg("malformed SCRAM message"),
                         errdetail("Comma expected, but found character \"%s\".",
-                                  sanitize_char(*input))));
-           input++;
+                                  sanitize_char(*p))));
+           p++;
            break;
        case 'y':
 
@@ -926,14 +926,14 @@ read_client_first_message(scram_state *state, char *input)
                         errdetail("The client supports SCRAM channel binding but thinks the server does not.  "
                                   "However, this server does support channel binding.")));
 #endif
-           input++;
-           if (*input != ',')
+           p++;
+           if (*p != ',')
                ereport(ERROR,
                        (errcode(ERRCODE_PROTOCOL_VIOLATION),
                         errmsg("malformed SCRAM message"),
                         errdetail("Comma expected, but found character \"%s\".",
-                                  sanitize_char(*input))));
-           input++;
+                                  sanitize_char(*p))));
+           p++;
            break;
        case 'p':
 
@@ -947,7 +947,7 @@ read_client_first_message(scram_state *state, char *input)
                         errmsg("malformed SCRAM message"),
                         errdetail("The client selected SCRAM-SHA-256 without channel binding, but the SCRAM message includes channel binding data.")));
 
-           channel_binding_type = read_attr_value(&input, 'p');
+           channel_binding_type = read_attr_value(&p, 'p');
 
            /*
             * The only channel binding type we support is
@@ -964,25 +964,25 @@ read_client_first_message(scram_state *state, char *input)
                    (errcode(ERRCODE_PROTOCOL_VIOLATION),
                     errmsg("malformed SCRAM message"),
                     errdetail("Unexpected channel-binding flag \"%s\".",
-                              sanitize_char(*input))));
+                              sanitize_char(*p))));
    }
 
    /*
     * Forbid optional authzid (authorization identity).  We don't support it.
     */
-   if (*input == 'a')
+   if (*p == 'a')
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("client uses authorization identity, but it is not supported")));
-   if (*input != ',')
+   if (*p != ',')
        ereport(ERROR,
                (errcode(ERRCODE_PROTOCOL_VIOLATION),
                 errmsg("malformed SCRAM message"),
                 errdetail("Unexpected attribute \"%s\" in client-first-message.",
-                          sanitize_char(*input))));
-   input++;
+                          sanitize_char(*p))));
+   p++;
 
-   state->client_first_message_bare = pstrdup(input);
+   state->client_first_message_bare = pstrdup(p);
 
    /*
     * Any mandatory extensions would go here.  We don't support any.
@@ -991,7 +991,7 @@ read_client_first_message(scram_state *state, char *input)
     * but it can only be sent in the server-final message.  We prefer to fail
     * immediately (which the RFC also allows).
     */
-   if (*input == 'm')
+   if (*p == 'm')
        ereport(ERROR,
                (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("client requires an unsupported SCRAM extension")));
@@ -1001,10 +1001,10 @@ read_client_first_message(scram_state *state, char *input)
     * startup message instead, still it is kept around if provided as it
     * proves to be useful for debugging purposes.
     */
-   state->client_username = read_attr_value(&input, 'n');
+   state->client_username = read_attr_value(&p, 'n');
 
    /* read nonce and check that it is made of only printable characters */
-   state->client_nonce = read_attr_value(&input, 'r');
+   state->client_nonce = read_attr_value(&p, 'r');
    if (!is_scram_printable(state->client_nonce))
        ereport(ERROR,
                (errcode(ERRCODE_PROTOCOL_VIOLATION),
@@ -1014,8 +1014,8 @@ read_client_first_message(scram_state *state, char *input)
     * There can be any number of optional extensions after this.  We don't
     * support any extensions, so ignore them.
     */
-   while (*input != '\0')
-       read_any_attr(&input, NULL);
+   while (*p != '\0')
+       read_any_attr(&p, NULL);
 
    /* success! */
 }
@@ -1144,7 +1144,7 @@ build_server_first_message(scram_state *state)
  * Read and parse the final message received from client.
  */
 static void
-read_client_final_message(scram_state *state, char *input)
+read_client_final_message(scram_state *state, const char *input)
 {
    char        attr;
    char       *channel_binding;

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index c42f7b8fe6a3fa2414889e1fde254924f3583e33..d5115aad729888940b3ce914194f7cb2d3251e51 100644 (file)
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -985,7 +985,7 @@ CheckSCRAMAuth(Port *port, char *shadow_pass, char **logdetail)
         * we pass 'logdetail' as NULL when doing a mock authentication,
         * because we should already have a better error message in that case
         */
-       result = pg_be_scram_exchange(scram_opaq, unconstify(char *, input), inputlen,
+       result = pg_be_scram_exchange(scram_opaq, input, inputlen,
                                      &output, &outputlen,
                                      logdetail);
 

diff --git a/src/include/libpq/scram.h b/src/include/libpq/scram.h
index 8eeb8807e913fdc25b2f1e2cf1871d1d1ff80f33..d7f4c094c9df760727762fdeb41865fa89f6bc16 100644 (file)
--- a/src/include/libpq/scram.h
+++ b/src/include/libpq/scram.h
@@ -24,7 +24,7 @@
 /* Routines dedicated to authentication */
 extern void pg_be_scram_get_mechanisms(Port *port, StringInfo buf);
 extern void *pg_be_scram_init(Port *port, const char *selected_mech, const char *shadow_pass);
-extern int pg_be_scram_exchange(void *opaq, char *input, int inputlen,
+extern int pg_be_scram_exchange(void *opaq, const char *input, int inputlen,
                     char **output, int *outputlen, char **logdetail);
 
 /* Routines to handle and check SCRAM-SHA-256 verifier */