[edk2-devel] [PATCH v3 1/1] ShellPkg/CommandLib: avoid NULL derefence and memory leak

[Carsey, Jaben]

Reviewed-by: Jaben Carsey <jaben.carsey at intel.com>

Code change looks good visually.


> -----Original Message-----
> From: devel at edk2.groups.io [mailto:devel at edk2.groups.io] On Behalf Of
> Heinrich Schuchardt
> Sent: Thursday, May 09, 2019 8:24 PM
> To: Gao, Zhichao <zhichao.gao at intel.com>
> Cc: devel @ edk2 . groups . io <devel at edk2.groups.io>; Carsey, Jaben
> <jaben.carsey at intel.com>; Ni, Ray <ray.ni at intel.com>; Leif Lindholm
> <leif.lindholm at linaro.org>; Gao, Liming <liming.gao at intel.com>; Heinrich
> Schuchardt <xypron.glpk at gmx.de>
> Subject: [edk2-devel] [PATCH v3 1/1] ShellPkg/CommandLib: avoid NULL
> derefence and memory leak
> Importance: High
> 
> Since TianoCore EDK2 commit d65f2cea36d1 ("ShellPkg/CommandLib: Locate
> proper UnicodeCollation instance") in edk2 the UEFI Shell crashes if EFI
> variable PlatformLang is not defined due to dereferencing gUnicodeCollation
> gUnicodeCollation (= NULL) in ShellCommandRegisterCommandName().
> 
> Furthermore CommandInit() is leaking PlatformLang if
> gUnicodeCollation != NULL.
> 
> Close the memory leak and use the first UnicodeCollation instance if
> PlatfomLang is not defined.
> 
> Fixes: d65f2cea36d1 ("ShellPkg/CommandLib: Locate proper
> UnicodeCollation
> instance")
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
> Reviewed-by: Zhichao Gao <zhichao.gao at intel.com>
> ---
> v3
> 	resend as quoted-printable
> ---
>  .../UefiShellCommandLib/UefiShellCommandLib.c | 20 +++++++++++++-----
> -
>  1 file changed, 14 insertions(+), 6 deletions(-)
> 
> diff --git a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
> b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
> index ddc4bb1567..e60279e5ac 100644
> --- a/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
> +++ b/ShellPkg/Library/UefiShellCommandLib/UefiShellCommandLib.c
> @@ -80,12 +80,10 @@ CommandInit(
>    EFI_STATUS                      Status;
> 
>    CHAR8                           *PlatformLang;
> 
> 
> 
> -  GetEfiGlobalVariable2 (EFI_PLATFORM_LANG_VARIABLE_NAME,
> (VOID**)&PlatformLang, NULL);
> 
> -  if (PlatformLang == NULL) {
> 
> -    return EFI_UNSUPPORTED;
> 
> -  }
> 
> -
> 
>    if (gUnicodeCollation == NULL) {
> 
> +
> 
> +    GetEfiGlobalVariable2 (EFI_PLATFORM_LANG_VARIABLE_NAME,
> (VOID**)&PlatformLang, NULL);
> 
> +
> 
>      Status = gBS->LocateHandleBuffer (
> 
>                      ByProtocol,
> 
>                      &gEfiUnicodeCollation2ProtocolGuid,
> 
> @@ -113,6 +111,14 @@ CommandInit(
>          continue;
> 
>        }
> 
> 
> 
> +      //
> 
> +      // Without clue provided use the first Unicode Collation2 protocol.
> 
> +      //
> 
> +      if (PlatformLang == NULL) {
> 
> +        gUnicodeCollation = Uc;
> 
> +        break;
> 
> +      }
> 
> +
> 
>        //
> 
>        // Find the best matching matching language from the supported
> languages
> 
>        // of Unicode Collation2 protocol.
> 
> @@ -132,7 +138,9 @@ CommandInit(
>      if (Handles != NULL) {
> 
>        FreePool (Handles);
> 
>      }
> 
> -    FreePool (PlatformLang);
> 
> +    if (PlatformLang != NULL) {
> 
> +      FreePool (PlatformLang);
> 
> +    }
> 
>    }
> 
> 
> 
>    return (gUnicodeCollation == NULL) ? EFI_UNSUPPORTED : EFI_SUCCESS;
> 
> --
> 2.20.1
> 
> 
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> [jaben.carsey at intel.com]
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