Re: [edk2-devel] [edk2-libc Patch] StdLib: Update libs for safe string functional issues

[Rebecca Cran]

Reviewed-by: Rebecca Cran <rebe...@nuviainc.com>

On 8/31/21 3:20 PM, Michael D Kinney wrote:

From: Jayaprakash Nevara <n.jayaprak...@intel.com>

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3361

Update use of safe string functions that incorrectly assume
that the maximum size of a string is UNICODE_STRING_MAX.
This assumption is breaking some standard C applications.

Cc: Rebecca Cran <rebe...@nuviainc.com>
Cc: Jayaprakash Nevara <n.jayaprak...@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kin...@intel.com>
---
  StdLib/LibC/StdLib/Environs.c           |  2 +-
  StdLib/LibC/StdLib/realpath.c           | 19 ++++++++++++++++---
  StdLib/LibC/String/Concatenation.c      |  4 ++--
  StdLib/LibC/String/Copying.c            |  5 ++---
  StdLib/LibC/Uefi/Devices/Utility/Path.c | 17 +++++++++++------
  StdLib/LibC/Uefi/SysCalls.c             |  8 ++++++--
  StdLib/LibC/Wchar/Concatenation.c       |  4 ++--
  StdLib/LibC/Wchar/Copying.c             |  4 ++--
  StdLib/PosixLib/GetPass/GetPass.c       | 11 +++++++----
  9 files changed, 49 insertions(+), 25 deletions(-)

diff --git a/StdLib/LibC/StdLib/Environs.c b/StdLib/LibC/StdLib/Environs.c
index ad56629..e8cfd6d 100644
--- a/StdLib/LibC/StdLib/Environs.c
+++ b/StdLib/LibC/StdLib/Environs.c
@@ -180,7 +180,7 @@ char   *getenv(const char *name)
    (void)AsciiStrToUnicodeStrS (name, gMD->UString, UNICODE_STRING_MAX);
    EfiEnv = ShellGetEnvironmentVariable(gMD->UString);
    if(EfiEnv != NULL) {
-    (void)UnicodeStrToAsciiStrS (EfiEnv, gMD->ASgetenv, UNICODE_STRING_MAX);
+    (void)UnicodeStrToAsciiStrS (EfiEnv, gMD->ASgetenv, ASCII_STRING_MAX);
      retval = gMD->ASgetenv;
    }

diff --git a/StdLib/LibC/StdLib/realpath.c b/StdLib/LibC/StdLib/realpath.c

index a8ff1e9..3d4118d 100644
--- a/StdLib/LibC/StdLib/realpath.c
+++ b/StdLib/LibC/StdLib/realpath.c
@@ -38,7 +38,9 @@ realpath(
    char *resolved_name
    )
  {
-  CHAR16 *Temp;
+  RETURN_STATUS  Status;
+  CHAR16         *Temp;
+
    if (file_name == NULL || resolved_name == NULL) {
      errno = EINVAL;
      return (NULL);
@@ -48,8 +50,19 @@ realpath(
      errno = ENOMEM;
      return (NULL);
    }
-  AsciiStrToUnicodeStrS (file_name, Temp, UNICODE_STRING_MAX);
+  Status = AsciiStrToUnicodeStrS (file_name, Temp, AsciiStrLen (file_name) + 
1);
+  if (RETURN_ERROR (Status)) {
+    errno = EINVAL;
+    return NULL;
+  }
+
    PathCleanUpDirectories(Temp);
-  UnicodeStrToAsciiStrS (Temp, resolved_name, UNICODE_STRING_MAX);
+
+  Status = UnicodeStrToAsciiStrS (Temp, resolved_name, AsciiStrLen (file_name) 
+ 1);
+  if (RETURN_ERROR (Status)) {
+    errno = EINVAL;
+    return NULL;
+  }
+
    return (resolved_name);
  }
diff --git a/StdLib/LibC/String/Concatenation.c 
b/StdLib/LibC/String/Concatenation.c
index f78836f..ed13588 100644
--- a/StdLib/LibC/String/Concatenation.c
+++ b/StdLib/LibC/String/Concatenation.c
@@ -29,7 +29,7 @@
  char *
  strcat(char * __restrict s1, const char * __restrict s2)
  {
-  AsciiStrCatS (s1, UNICODE_STRING_MAX, s2);
+  AsciiStrCatS (s1, AsciiStrLen (s1) + AsciiStrLen(s2) + 1, s2);
    return s1;
  }

@@ -45,7 +45,7 @@ strcat(char * __restrict s1, const char * __restrict s2)

  char *
  strncat(char * __restrict s1, const char * __restrict s2, size_t n)
  {
-  AsciiStrnCatS (s1, UNICODE_STRING_MAX, s2, n);
+  AsciiStrnCatS (s1, AsciiStrLen (s1) + 1 + (UINTN)n, s2, n);
    return s1;
  }

diff --git a/StdLib/LibC/String/Copying.c b/StdLib/LibC/String/Copying.c

index cc2077a..c296714 100644
--- a/StdLib/LibC/String/Copying.c
+++ b/StdLib/LibC/String/Copying.c
@@ -16,7 +16,6 @@

#include <LibConfig.h> -#include <limits.h>

  #include  <stdlib.h>
  #include  <string.h>

@@ -74,7 +73,7 @@ strcpy(char * __restrict s1, const char * __restrict s2) //while ( *s1++ = *s2++) /* Empty Body */;

    //return(s1ret);
-  AsciiStrCpyS (s1, UNICODE_STRING_MAX, s2);
+  AsciiStrCpyS (s1, AsciiStrLen (s2) + 1, s2);
    return s1;
  }

@@ -91,7 +90,7 @@ strcpy(char * __restrict s1, const char * __restrict s2)

  **/
  char     *strncpy(char * __restrict s1, const char * __restrict s2, size_t n)
  {
-  AsciiStrnCpyS (s1, UNICODE_STRING_MAX, s2, n);
+  AsciiStrnCpyS (s1, n, s2, n);
    return s1;
    //char *dest = s1;

diff --git a/StdLib/LibC/Uefi/Devices/Utility/Path.c b/StdLib/LibC/Uefi/Devices/Utility/Path.c

index fe19196..be315bf 100644
--- a/StdLib/LibC/Uefi/Devices/Utility/Path.c
+++ b/StdLib/LibC/Uefi/Devices/Utility/Path.c
@@ -105,12 +105,17 @@ ClassifyPath(
  wchar_t *
  NormalizePath( const char *path)
  {
-  wchar_t  *temp;
-  wchar_t  *OldPath;
-  wchar_t  *NewPath;
-  size_t    Length;
-
-  AsciiStrToUnicodeStrS (path, gMD->UString, UNICODE_STRING_MAX);
+  RETURN_STATUS  Status;
+  wchar_t        *temp;
+  wchar_t        *OldPath;
+  wchar_t        *NewPath;
+  size_t         Length;
+
+  Status = AsciiStrToUnicodeStrS (path, gMD->UString, UNICODE_STRING_MAX);
+  if (RETURN_ERROR (Status)) {
+    errno    = EINVAL;
+    EFIerrno = Status;
+  }
    OldPath = gMD->UString;
    Length  = wcslen(OldPath) + 1;

diff --git a/StdLib/LibC/Uefi/SysCalls.c b/StdLib/LibC/Uefi/SysCalls.c

index e83b723..0c8dcc1 100644
--- a/StdLib/LibC/Uefi/SysCalls.c
+++ b/StdLib/LibC/Uefi/SysCalls.c
@@ -1304,7 +1304,8 @@ write  (int fd, const void *buf, size_t nbyte)
  char
  *getcwd (char *buf, size_t size)
  {
-  CONST CHAR16 *Cwd;
+  RETURN_STATUS  Status;
+  CONST CHAR16   *Cwd;

if (size == 0 || buf == NULL) {

      errno = EINVAL;
@@ -1320,7 +1321,10 @@ char
      errno = ERANGE;
      return (NULL);
    }
-  UnicodeStrToAsciiStrS (Cwd, buf, UNICODE_STRING_MAX);
+  Status = UnicodeStrToAsciiStrS (Cwd, buf, size);
+  if (RETURN_ERROR (Status)) {
+    return NULL;
+  }
    return buf;
  }

diff --git a/StdLib/LibC/Wchar/Concatenation.c b/StdLib/LibC/Wchar/Concatenation.c

index 7289240..288e1d6 100644
--- a/StdLib/LibC/Wchar/Concatenation.c
+++ b/StdLib/LibC/Wchar/Concatenation.c
@@ -31,7 +31,7 @@
  **/
  wchar_t *wcscat(wchar_t * __restrict s1, const wchar_t * __restrict s2)
  {
-  StrCatS ((CHAR16 *)s1, UNICODE_STRING_MAX, (CONST CHAR16 *)s2);
+  StrCatS ((CHAR16 *)s1, StrLen (s1) + StrLen (s2) + 1, (CONST CHAR16 *)s2);
    return s1;
  }

@@ -45,6 +45,6 @@ wchar_t *wcscat(wchar_t * __restrict s1, const wchar_t * __restrict s2)

  **/
  wchar_t *wcsncat(wchar_t * __restrict s1, const wchar_t * __restrict s2, 
size_t n)
  {
-  StrnCatS ((CHAR16 *)s1, UNICODE_STRING_MAX, (CONST CHAR16 *)s2, (UINTN)n);
+  StrnCatS ((CHAR16 *)s1, StrLen (s1) + 1 + (UINTN)n, (CONST CHAR16 *)s2, 
(UINTN)n);
    return s1;
  }
diff --git a/StdLib/LibC/Wchar/Copying.c b/StdLib/LibC/Wchar/Copying.c
index 848c834..45ceda7 100644
--- a/StdLib/LibC/Wchar/Copying.c
+++ b/StdLib/LibC/Wchar/Copying.c
@@ -29,7 +29,7 @@
  **/
  wchar_t *wcscpy(wchar_t * __restrict s1, const wchar_t * __restrict s2)
  {
-  return (wchar_t *)StrCpyS ((CHAR16 *)s1, UNICODE_STRING_MAX, (CONST CHAR16 
*)s2);
+  return (wchar_t *)StrCpyS ((CHAR16 *)s1, StrLen (s2) + 1, (CONST CHAR16 
*)s2);
  }

/** The wcsncpy function copies not more than n wide characters (those that

@@ -44,7 +44,7 @@ wchar_t *wcscpy(wchar_t * __restrict s1, const wchar_t * 
__restrict s2)
  **/
  wchar_t *wcsncpy(wchar_t * __restrict s1, const wchar_t * __restrict s2, 
size_t n)
  {
-  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, UNICODE_STRING_MAX, (CONST CHAR16 
*)s2, (UINTN)n);
+  return (wchar_t *)StrnCpyS ((CHAR16 *)s1, (UINTN)n, (CONST CHAR16 *)s2, 
(UINTN)n);
  }

/** The wmemcpy function copies n wide characters from the object pointed to by

diff --git a/StdLib/PosixLib/GetPass/GetPass.c 
b/StdLib/PosixLib/GetPass/GetPass.c
index 8657827..f14c59e 100644
--- a/StdLib/PosixLib/GetPass/GetPass.c
+++ b/StdLib/PosixLib/GetPass/GetPass.c
@@ -15,14 +15,14 @@
  #include <Library/MemoryAllocationLib.h>
  #include <Library/UefiLib.h>
  #include <Library/PcdLib.h>
-#include <limits.h>

static CHAR8 *ReturnStringAscii = NULL; char *getpass(const char *Prompt)

  {
-  BOOLEAN Ascii;
-  CHAR16  *ReturnString;
+  RETURN_STATUS  Status;
+  BOOLEAN        Ascii;
+  CHAR16         *ReturnString;

Ascii = FALSE; @@ -38,7 +38,10 @@ char *getpass(const char *Prompt)

      return (NULL);
    }

- UnicodeStrToAsciiStrS(ReturnString, ReturnStringAscii, UNICODE_STRING_MAX);

+  Status = UnicodeStrToAsciiStrS(ReturnString, ReturnStringAscii, StrLen 
(ReturnString) + 1);
+  if (RETURN_ERROR (Status)) {
+    ReturnStringAscii = NULL;
+  }

FreePool(ReturnString);

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