From dbfcdc186dc4c4791523dcd43c2f060f687cd763 Mon Sep 17 00:00:00 2001
From: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
Date: Thu, 15 Aug 2024 20:44:17 +0300
Subject: [PATCH] CryptoPkg/BaseCryptLib[MbedTls]/SysCall/TimerWrapper.c: fix
 memory leak

Make gmtime() return pointer to a statically allocated storage.  This
is how it's documented and that's how it gets used.  The API isn't
thread-safe but given that EDK2 is essentially single-threaded (MP
Services Protocol is a special exception).

Given that this code gets run at runtime phase, the leak could
potentially be used to exhaust memory reserved for the runtime phase.

Signed-off-by: Sergii Dmytruk <sergii.dmytruk@3mdeb.com>
---
 .../BaseCryptLib/SysCall/TimerWrapper.c       | 34 ++++++++-----------
 .../SysCall/TimerWrapper.c                    | 34 ++++++++-----------
 2 files changed, 30 insertions(+), 38 deletions(-)

diff --git a/CryptoPkg/Library/BaseCryptLib/SysCall/TimerWrapper.c b/CryptoPkg/Library/BaseCryptLib/SysCall/TimerWrapper.c
index 894aeb016f..54fa955817 100644
--- a/CryptoPkg/Library/BaseCryptLib/SysCall/TimerWrapper.c
+++ b/CryptoPkg/Library/BaseCryptLib/SysCall/TimerWrapper.c
@@ -169,7 +169,8 @@ gmtime (
   const time_t  *timer
   )
 {
-  struct tm  *GmTime;
+  STATIC struct tm  GmTime;
+
   UINT64     DayNo;
   UINT64     DayRemainder;
   time_t     Year;
@@ -182,23 +183,18 @@ gmtime (
     return NULL;
   }
 
-  GmTime = malloc (sizeof (struct tm));
-  if (GmTime == NULL) {
-    return NULL;
-  }
-
-  ZeroMem ((VOID *)GmTime, (UINTN)sizeof (struct tm));
+  ZeroMem ((VOID *)&GmTime, (UINTN)sizeof (GmTime));
 
   DayNo        = (UINT64)DivS64x64Remainder (*timer, SECSPERDAY, &Remainder);
   DayRemainder = (UINT64)Remainder;
 
   DivS64x64Remainder (DayRemainder, SECSPERMIN, &Remainder);
-  GmTime->tm_sec = (int)Remainder;
+  GmTime.tm_sec = (int)Remainder;
   DivS64x64Remainder (DayRemainder, SECSPERHOUR, &Remainder);
-  GmTime->tm_min  = (int)DivS64x64Remainder (Remainder, SECSPERMIN, NULL);
-  GmTime->tm_hour = (int)DivS64x64Remainder (DayRemainder, SECSPERHOUR, NULL);
+  GmTime.tm_min  = (int)DivS64x64Remainder (Remainder, SECSPERMIN, NULL);
+  GmTime.tm_hour = (int)DivS64x64Remainder (DayRemainder, SECSPERHOUR, NULL);
   DivS64x64Remainder ((DayNo + 4), 7, &Remainder);
-  GmTime->tm_wday = (int)Remainder;
+  GmTime.tm_wday = (int)Remainder;
 
   for (Year = 1970, YearNo = 0; DayNo > 0; Year++) {
     TotalDays = (UINT32)(IsLeap (Year) ? 366 : 365);
@@ -210,8 +206,8 @@ gmtime (
     }
   }
 
-  GmTime->tm_year = (int)(YearNo + (1970 - 1900));
-  GmTime->tm_yday = (int)DayNo;
+  GmTime.tm_year = (int)(YearNo + (1970 - 1900));
+  GmTime.tm_yday = (int)DayNo;
 
   for (MonthNo = 12; MonthNo > 1; MonthNo--) {
     if (DayNo >= CumulativeDays[IsLeap (Year)][MonthNo]) {
@@ -220,14 +216,14 @@ gmtime (
     }
   }
 
-  GmTime->tm_mon  = (int)MonthNo - 1;
-  GmTime->tm_mday = (int)DayNo + 1;
+  GmTime.tm_mon  = (int)MonthNo - 1;
+  GmTime.tm_mday = (int)DayNo + 1;
 
-  GmTime->tm_isdst  = 0;
-  GmTime->tm_gmtoff = 0;
-  GmTime->tm_zone   = NULL;
+  GmTime.tm_isdst  = 0;
+  GmTime.tm_gmtoff = 0;
+  GmTime.tm_zone   = NULL;
 
-  return GmTime;
+  return &GmTime;
 }
 
 unsigned int
diff --git a/CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/TimerWrapper.c b/CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/TimerWrapper.c
index 0db9c8602e..4e164197e4 100644
--- a/CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/TimerWrapper.c
+++ b/CryptoPkg/Library/BaseCryptLibMbedTls/SysCall/TimerWrapper.c
@@ -113,7 +113,8 @@ gmtime (
   const time_t  *timer
   )
 {
-  struct tm  *GmTime;
+  STATIC struct tm  GmTime;
+
   UINT16     DayNo;
   UINT16     DayRemainder;
   time_t     Year;
@@ -125,20 +126,15 @@ gmtime (
     return NULL;
   }
 
-  GmTime = AllocateZeroPool (sizeof (struct tm));
-  if (GmTime == NULL) {
-    return NULL;
-  }
-
-  ZeroMem ((VOID *)GmTime, (UINTN)sizeof (struct tm));
+  ZeroMem ((VOID *)&GmTime, (UINTN)sizeof (GmTime));
 
   DayNo        = (UINT16)(*timer / SECSPERDAY);
   DayRemainder = (UINT16)(*timer % SECSPERDAY);
 
-  GmTime->tm_sec  = (int)(DayRemainder % SECSPERMIN);
-  GmTime->tm_min  = (int)((DayRemainder % SECSPERHOUR) / SECSPERMIN);
-  GmTime->tm_hour = (int)(DayRemainder / SECSPERHOUR);
-  GmTime->tm_wday = (int)((DayNo + 4) % 7);
+  GmTime.tm_sec  = (int)(DayRemainder % SECSPERMIN);
+  GmTime.tm_min  = (int)((DayRemainder % SECSPERHOUR) / SECSPERMIN);
+  GmTime.tm_hour = (int)(DayRemainder / SECSPERHOUR);
+  GmTime.tm_wday = (int)((DayNo + 4) % 7);
 
   for (Year = 1970, YearNo = 0; DayNo > 0; Year++) {
     TotalDays = (UINT16)(IsLeap (Year) ? 366 : 365);
@@ -150,8 +146,8 @@ gmtime (
     }
   }
 
-  GmTime->tm_year = (int)(YearNo + (1970 - 1900));
-  GmTime->tm_yday = (int)DayNo;
+  GmTime.tm_year = (int)(YearNo + (1970 - 1900));
+  GmTime.tm_yday = (int)DayNo;
 
   for (MonthNo = 12; MonthNo > 1; MonthNo--) {
     if (DayNo >= CumulativeDays[IsLeap (Year)][MonthNo]) {
@@ -160,14 +156,14 @@ gmtime (
     }
   }
 
-  GmTime->tm_mon  = (int)MonthNo - 1;
-  GmTime->tm_mday = (int)DayNo + 1;
+  GmTime.tm_mon  = (int)MonthNo - 1;
+  GmTime.tm_mday = (int)DayNo + 1;
 
-  GmTime->tm_isdst  = 0;
-  GmTime->tm_gmtoff = 0;
-  GmTime->tm_zone   = NULL;
+  GmTime.tm_isdst  = 0;
+  GmTime.tm_gmtoff = 0;
+  GmTime.tm_zone   = NULL;
 
-  return GmTime;
+  return &GmTime;
 }
 
 /**_time64 function. **/