[PATCH v2 3/8] CryptoPkg/Crt: turn strchr() into a function (CVE-2019-14553)

["Laszlo Ersek" <lersek@redhat.com>]

According to the ISO C standard, strchr() is a function. We #define it as
a macro. Unfortunately, our macro evaluates the first argument ("str")
twice. If the expression passed for "str" has side effects, the behavior
may be undefined.

In a later patch in this series, we're going to resurrect "inet_pton.c"
(originally from the StdLib package), which calls strchr() just like that:

  strchr((xdigits = xdigits_l), ch)
  strchr((xdigits = xdigits_u), ch)

To enable this kind of function call, turn strchr() into a function.

Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Sivaraman Nainar <sivaramann@amiindia.co.in>
Cc: Xiaoyu Lu <xiaoyux.lu@intel.com>
Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=960
CVE: CVE-2019-14553
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
---

Notes:
    v2:
    - new patch

 CryptoPkg/Library/Include/CrtLibSupport.h           | 2 +-
 CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/CryptoPkg/Library/Include/CrtLibSupport.h b/CryptoPkg/Library/Include/CrtLibSupport.h
index 5806f50f7485..b90da20ff7e7 100644
--- a/CryptoPkg/Library/Include/CrtLibSupport.h
+++ b/CryptoPkg/Library/Include/CrtLibSupport.h
@@ -146,8 +146,9 @@ int            isalnum     (int);
 int            isupper     (int);
 int            tolower     (int);
 int            strcmp      (const char *, const char *);
 int            strncasecmp (const char *, const char *, size_t);
+char           *strchr     (const char *, int);
 char           *strrchr    (const char *, int);
 unsigned long  strtoul     (const char *, char **, int);
 long           strtol      (const char *, char **, int);
 char           *strerror   (int);
@@ -187,9 +188,8 @@ void           abort       (void);
 #define strlen(str)                       (size_t)(AsciiStrnLenS(str,MAX_STRING_SIZE))
 #define strcpy(strDest,strSource)         AsciiStrCpyS(strDest,MAX_STRING_SIZE,strSource)
 #define strncpy(strDest,strSource,count)  AsciiStrnCpyS(strDest,MAX_STRING_SIZE,strSource,(UINTN)count)
 #define strcat(strDest,strSource)         AsciiStrCatS(strDest,MAX_STRING_SIZE,strSource)
-#define strchr(str,ch)                    ScanMem8((VOID *)(str),AsciiStrSize(str),(UINT8)ch)
 #define strncmp(string1,string2,count)    (int)(AsciiStrnCmp(string1,string2,(UINTN)(count)))
 #define strcasecmp(str1,str2)             (int)AsciiStriCmp(str1,str2)
 #define sprintf(buf,...)                  AsciiSPrint(buf,MAX_STRING_SIZE,__VA_ARGS__)
 #define localtime(timer)                  NULL
diff --git a/CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c b/CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c
index 71a2ef34ed2b..42235ab96ac3 100644
--- a/CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c
+++ b/CryptoPkg/Library/BaseCryptLib/SysCall/CrtWrapper.c
@@ -114,8 +114,13 @@ QuickSortWorker (
 //
 // -- String Manipulation Routines --
 //
 
+char *strchr(const char *str, int ch)
+{
+  return ScanMem8 (str, AsciiStrSize (str), (UINT8)ch);
+}
+
 /* Scan a string for the last occurrence of a character */
 char *strrchr (const char *str, int c)
 {
   char * save;
-- 
2.19.1.3.g30247aa5d201