From f010e18ff0bae6ffedaf0ecfc47f04af22f9fff9 Mon Sep 17 00:00:00 2001
From: facetosea <25808407@qq.com>
Date: Wed, 17 Jan 2024 18:28:00 +0800
Subject: [PATCH] fix: LEASTSQUARES func result stack overflow

---
 include/libs/function/function.h        |  4 ++++
 source/libs/function/src/builtins.c     |  2 +-
 source/libs/function/src/builtinsimpl.c | 14 ++++++++++++--
 source/libs/scalar/src/sclfunc.c        | 16 +++++++++++++---
 4 files changed, 30 insertions(+), 6 deletions(-)

diff --git a/include/libs/function/function.h b/include/libs/function/function.h
index ffaad69373..8863201094 100644
--- a/include/libs/function/function.h
+++ b/include/libs/function/function.h
@@ -249,6 +249,10 @@ typedef struct SPoint {
 int32_t taosGetLinearInterpolationVal(SPoint *point, int32_t outputType, SPoint *point1, SPoint *point2,
                                       int32_t inputType);
 
+#define LEASTSQUARES_DOUBLE_ITEM_LENGTH 25
+#define LEASTSQUARES_BUFF_LENGTH 128
+#define DOUBLE_PRECISION_DIGITS "16e"
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/libs/function/src/builtins.c b/source/libs/function/src/builtins.c
index 5424a5c704..6f5b28f366 100644
--- a/source/libs/function/src/builtins.c
+++ b/source/libs/function/src/builtins.c
@@ -952,7 +952,7 @@ static int32_t translateLeastSQR(SFunctionNode* pFunc, char* pErrBuf, int32_t le
     }
   }
 
-  pFunc->node.resType = (SDataType){.bytes = 64, .type = TSDB_DATA_TYPE_BINARY};
+  pFunc->node.resType = (SDataType){.bytes = LEASTSQUARES_BUFF_LENGTH, .type = TSDB_DATA_TYPE_BINARY};
   return TSDB_CODE_SUCCESS;
 }
 
diff --git a/source/libs/function/src/builtinsimpl.c b/source/libs/function/src/builtinsimpl.c
index 1e71954278..000f634fe5 100644
--- a/source/libs/function/src/builtinsimpl.c
+++ b/source/libs/function/src/builtinsimpl.c
@@ -1576,9 +1576,19 @@ int32_t leastSQRFinalize(SqlFunctionCtx* pCtx, SSDataBlock* pBlock) {
 
   param12 /= param[1][1];
 
-  char   buf[512] = {0};
+  char buf[LEASTSQUARES_BUFF_LENGTH] = {0};
+  char slopBuf[64] = {0};
+  char interceptBuf[64] = {0};
+  int  n = snprintf(slopBuf, 64, "%.6lf", param02);
+  if (n > LEASTSQUARES_DOUBLE_ITEM_LENGTH) {
+    snprintf(slopBuf, 64, "%." DOUBLE_PRECISION_DIGITS, param02);
+  }
+  n = snprintf(interceptBuf, 64, "%.6lf", param12);
+  if (n > LEASTSQUARES_DOUBLE_ITEM_LENGTH) {
+    snprintf(interceptBuf, 64, "%." DOUBLE_PRECISION_DIGITS, param12);
+  }
   size_t len =
-      snprintf(varDataVal(buf), sizeof(buf) - VARSTR_HEADER_SIZE, "{slop:%.6lf, intercept:%.6lf}", param02, param12);
+      snprintf(varDataVal(buf), sizeof(buf) - VARSTR_HEADER_SIZE, "{slop:%s, intercept:%s}", slopBuf, interceptBuf);
   varDataSetLen(buf, len);
 
   colDataSetVal(pCol, currentRow, buf, pResInfo->isNullRes);
diff --git a/source/libs/scalar/src/sclfunc.c b/source/libs/scalar/src/sclfunc.c
index e713043b80..2e44c75c17 100644
--- a/source/libs/scalar/src/sclfunc.c
+++ b/source/libs/scalar/src/sclfunc.c
@@ -2427,9 +2427,19 @@ int32_t leastSQRScalarFunction(SScalarParam *pInput, int32_t inputNum, SScalarPa
 
     matrix12 /= matrix[1][1];
 
-    char   buf[64] = {0};
-    size_t len = snprintf(varDataVal(buf), sizeof(buf) - VARSTR_HEADER_SIZE, "{slop:%.6lf, intercept:%.6lf}", matrix02,
-                          matrix12);
+    char buf[LEASTSQUARES_BUFF_LENGTH] = {0};
+    char slopBuf[64] = {0};
+    char interceptBuf[64] = {0};
+    int  n = snprintf(slopBuf, 64, "%.6lf", matrix02);
+    if (n > LEASTSQUARES_DOUBLE_ITEM_LENGTH) {
+      snprintf(slopBuf, 64, "%." DOUBLE_PRECISION_DIGITS, matrix02);
+    }
+    n = snprintf(interceptBuf, 64, "%.6lf", matrix12);
+    if (n > LEASTSQUARES_DOUBLE_ITEM_LENGTH) {
+      snprintf(interceptBuf, 64, "%." DOUBLE_PRECISION_DIGITS, matrix12);
+    }
+    size_t len =
+        snprintf(varDataVal(buf), sizeof(buf) - VARSTR_HEADER_SIZE, "{slop:%s, intercept:%s}", slopBuf, interceptBuf);
     varDataSetLen(buf, len);
     colDataSetVal(pOutputData, 0, buf, false);
   }