libpq/SOURCES/postgresql-CVE-2026-6477.patch
2026-06-22 02:16:58 -04:00

220 lines
7.9 KiB
Diff

From 2b450648240c6c56f367e74bbf0f785b91f93396 Mon Sep 17 00:00:00 2001
From: Petr Khartskhaev <pkhartsk@redhat.com>
Date: Wed, 3 Jun 2026 16:34:32 +0200
Subject: [PATCH] fix CVE-2026-6477
---
doc/src/sgml/libpq.sgml | 11 +-
src/interfaces/libpq/fe-exec.c | 18 +-
src/interfaces/libpq/fe-lobj.c | 12 +-
src/interfaces/libpq/fe-protocol2.c | 16 +-
src/interfaces/libpq/fe-protocol3.c | 14 +-
src/interfaces/libpq/libpq-int.h | 9 +-
13 files changed, 17098 insertions(+), 15 deletions(-)
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 1a84241..e1f688c 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -5086,15 +5086,20 @@ int PQrequestCancel(PGconn *conn);
to send simple function calls to the server.
</para>
- <tip>
+ <warning>
<para>
- This interface is somewhat obsolete, as one can achieve similar
+ This interface is unsafe and should not be used. When
+ <parameter>result_is_int</parameter> is set to <literal>0</literal>,
+ <function>PQfn</function> may write data beyond the end of
+ <parameter>result_buf</parameter>, regardless of whether the buffer has
+ enough space for the requested number of bytes. Furthermore, it is
+ obsolete, as one can achieve similar
performance and greater functionality by setting up a prepared
statement to define the function call. Then, executing the statement
with binary transmission of parameters and results substitutes for a
fast-path function call.
</para>
- </tip>
+ </warning>
<para>
The function <function id="libpq-PQfn">PQfn</function><indexterm><primary>PQfn</primary></indexterm>
diff --git a/src/interfaces/libpq/fe-exec.c b/src/interfaces/libpq/fe-exec.c
index b30b565..076a9d0 100644
--- a/src/interfaces/libpq/fe-exec.c
+++ b/src/interfaces/libpq/fe-exec.c
@@ -2665,6 +2665,20 @@ PQfn(PGconn *conn,
int result_is_int,
const PQArgBlock *args,
int nargs)
+{
+ return PQnfn(conn, fnid, result_buf, -1, result_len,
+ result_is_int, args, nargs);
+}
+
+/*
+ * PQnfn
+ * Private version of PQfn() with verification that returned data fits in
+ * result_buf when result_is_int == 0. Setting buf_size to -1 disables
+ * this verification.
+ */
+PGresult *
+PQnfn(PGconn *conn, int fnid, int *result_buf, int buf_size, int *result_len,
+ int result_is_int, const PQArgBlock *args, int nargs)
{
*result_len = 0;
@@ -2684,12 +2698,12 @@ PQfn(PGconn *conn,
if (PG_PROTOCOL_MAJOR(conn->pversion) >= 3)
return pqFunctionCall3(conn, fnid,
- result_buf, result_len,
+ result_buf, buf_size, result_len,
result_is_int,
args, nargs);
else
return pqFunctionCall2(conn, fnid,
- result_buf, result_len,
+ result_buf, buf_size, result_len,
result_is_int,
args, nargs);
}
diff --git a/src/interfaces/libpq/fe-lobj.c b/src/interfaces/libpq/fe-lobj.c
index a94ce06..01e67a3 100644
--- a/src/interfaces/libpq/fe-lobj.c
+++ b/src/interfaces/libpq/fe-lobj.c
@@ -288,8 +288,8 @@ lo_read(PGconn *conn, int fd, char *buf, size_t len)
argv[1].len = 4;
argv[1].u.integer = (int) len;
- res = PQfn(conn, conn->lobjfuncs->fn_lo_read,
- (void *) buf, &result_len, 0, argv, 2);
+ res = PQnfn(conn, conn->lobjfuncs->fn_lo_read,
+ (void *) buf, len, &result_len, 0, argv, 2);
if (PQresultStatus(res) == PGRES_COMMAND_OK)
{
PQclear(res);
@@ -439,8 +439,8 @@ lo_lseek64(PGconn *conn, int fd, pg_int64 offset, int whence)
argv[2].len = 4;
argv[2].u.integer = whence;
- res = PQfn(conn, conn->lobjfuncs->fn_lo_lseek64,
- (void *) &retval, &result_len, 0, argv, 3);
+ res = PQnfn(conn, conn->lobjfuncs->fn_lo_lseek64,
+ (void *) &retval, sizeof(retval), &result_len, 0, argv, 3);
if (PQresultStatus(res) == PGRES_COMMAND_OK && result_len == 8)
{
PQclear(res);
@@ -605,8 +605,8 @@ lo_tell64(PGconn *conn, int fd)
argv[0].len = 4;
argv[0].u.integer = fd;
- res = PQfn(conn, conn->lobjfuncs->fn_lo_tell64,
- (void *) &retval, &result_len, 0, argv, 1);
+ res = PQnfn(conn, conn->lobjfuncs->fn_lo_tell64,
+ (void *) &retval, sizeof(retval), &result_len, 0, argv, 1);
if (PQresultStatus(res) == PGRES_COMMAND_OK && result_len == 8)
{
PQclear(res);
diff --git a/src/interfaces/libpq/fe-protocol2.c b/src/interfaces/libpq/fe-protocol2.c
index 9360c54..0c2b629 100644
--- a/src/interfaces/libpq/fe-protocol2.c
+++ b/src/interfaces/libpq/fe-protocol2.c
@@ -1428,7 +1428,7 @@ pqEndcopy2(PGconn *conn)
*/
PGresult *
pqFunctionCall2(PGconn *conn, Oid fnid,
- int *result_buf, int *actual_result_len,
+ int *result_buf, int buf_size, int *actual_result_len,
int result_is_int,
const PQArgBlock *args, int nargs)
{
@@ -1510,6 +1510,20 @@ pqFunctionCall2(PGconn *conn, Oid fnid,
}
else
{
+ /*
+ * If the server returned too much data for the
+ * buffer, something fishy is going on. Abandon ship.
+ */
+ if (buf_size != -1 && *actual_result_len > buf_size)
+ {
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext("server returned too much data\n"));
+ conn->asyncStatus = PGASYNC_READY;
+ pqDropConnection(conn, true);
+ conn->status = CONNECTION_BAD;
+ return pqPrepareAsyncResult(conn);
+ }
+
if (pqGetnchar((char *) result_buf,
*actual_result_len,
conn))
diff --git a/src/interfaces/libpq/fe-protocol3.c b/src/interfaces/libpq/fe-protocol3.c
index 3da1ace..a092010 100644
--- a/src/interfaces/libpq/fe-protocol3.c
+++ b/src/interfaces/libpq/fe-protocol3.c
@@ -1903,7 +1903,7 @@ pqEndcopy3(PGconn *conn)
*/
PGresult *
pqFunctionCall3(PGconn *conn, Oid fnid,
- int *result_buf, int *actual_result_len,
+ int *result_buf, int buf_size, int *actual_result_len,
int result_is_int,
const PQArgBlock *args, int nargs)
{
@@ -2034,6 +2034,18 @@ pqFunctionCall3(PGconn *conn, Oid fnid,
}
else
{
+ /*
+ * If the server returned too much data for the
+ * buffer, something fishy is going on. Abandon ship.
+ */
+ if (buf_size != -1 && *actual_result_len > buf_size)
+ {
+ appendPQExpBufferStr(&conn->errorMessage,
+ libpq_gettext("server returned too much data\n"));
+ handleSyncLoss(conn, id, *actual_result_len);
+ return pqPrepareAsyncResult(conn);
+ }
+
if (pqGetnchar((char *) result_buf,
*actual_result_len,
conn))
diff --git a/src/interfaces/libpq/libpq-int.h b/src/interfaces/libpq/libpq-int.h
index 814884a..1b0cf91 100644
--- a/src/interfaces/libpq/libpq-int.h
+++ b/src/interfaces/libpq/libpq-int.h
@@ -622,6 +622,9 @@ extern void pqSaveMessageField(PGresult *res, char code,
extern void pqSaveParameterStatus(PGconn *conn, const char *name,
const char *value);
extern int pqRowProcessor(PGconn *conn, const char **errmsgp);
+extern PGresult *PQnfn(PGconn *conn, int fnid, int *result_buf, int buf_size,
+ int *result_len, int result_is_int,
+ const PQArgBlock *args, int nargs);
/* === in fe-protocol2.c === */
@@ -635,7 +638,8 @@ extern int pqGetline2(PGconn *conn, char *s, int maxlen);
extern int pqGetlineAsync2(PGconn *conn, char *buffer, int bufsize);
extern int pqEndcopy2(PGconn *conn);
extern PGresult *pqFunctionCall2(PGconn *conn, Oid fnid,
- int *result_buf, int *actual_result_len,
+ int *result_buf, int buf_size,
+ int *actual_result_len,
int result_is_int,
const PQArgBlock *args, int nargs);
@@ -652,7 +656,8 @@ extern int pqGetline3(PGconn *conn, char *s, int maxlen);
extern int pqGetlineAsync3(PGconn *conn, char *buffer, int bufsize);
extern int pqEndcopy3(PGconn *conn);
extern PGresult *pqFunctionCall3(PGconn *conn, Oid fnid,
- int *result_buf, int *actual_result_len,
+ int *result_buf, int buf_size,
+ int *actual_result_len,
int result_is_int,
const PQArgBlock *args, int nargs);