Re: [edk2-devel] [PATCH 1/1] MdePkg/BaseLib: Fix invalid memory access in AArch64 SetJump/LongJump

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

On 09/29/20 03:12, Jan Bobek wrote:
> Correct the memory offsets used in REG_ONE/REG_PAIR macros to
> synchronize them with definition of the BASE_LIBRARY_JUMP_BUFFER
> structure on AArch64.
> 
> The REG_ONE macro declares only a single 64-bit register be
> read/written; however, the subsequent offset has previously been 16
> bytes larger, creating an unused memory gap in the middle of the
> structure and causing SetJump/LongJump functions to read/write 8 bytes
> of memory past the end of the jump buffer struct.
> 
> Signed-off-by: Jan Bobek <jbobek@nvidia.com>
> ---
>  MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S   | 8 ++++----
>  MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm | 8 ++++----
>  2 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S b/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S
> index 72cea259e9..deefdf526b 100644
> --- a/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S
> +++ b/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.S
> @@ -20,10 +20,10 @@ GCC_ASM_EXPORT(InternalLongJump)
>          REG_ONE  (x16,      96) /*IP0*/
> 
>  
> 
>  #define FPR_LAYOUT                      \
> 
> -        REG_PAIR ( d8,  d9, 112);       \
> 
> -        REG_PAIR (d10, d11, 128);       \
> 
> -        REG_PAIR (d12, d13, 144);       \
> 
> -        REG_PAIR (d14, d15, 160);
> 
> +        REG_PAIR ( d8,  d9, 104);       \
> 
> +        REG_PAIR (d10, d11, 120);       \
> 
> +        REG_PAIR (d12, d13, 136);       \
> 
> +        REG_PAIR (d14, d15, 152);
> 
>  
> 
>  #/**
> 
>  #  Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
> 
> diff --git a/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm b/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm
> index 20dd0f1b85..df70f29899 100644
> --- a/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm
> +++ b/MdePkg/Library/BaseLib/AArch64/SetJumpLongJump.asm
> @@ -19,10 +19,10 @@
>          REG_ONE  (x16,      #96) /*IP0*/
> 
>  
> 
>  #define FPR_LAYOUT                       \
> 
> -        REG_PAIR ( d8,  d9, #112);       \
> 
> -        REG_PAIR (d10, d11, #128);       \
> 
> -        REG_PAIR (d12, d13, #144);       \
> 
> -        REG_PAIR (d14, d15, #160);
> 
> +        REG_PAIR ( d8,  d9, #104);       \
> 
> +        REG_PAIR (d10, d11, #120);       \
> 
> +        REG_PAIR (d12, d13, #136);       \
> 
> +        REG_PAIR (d14, d15, #152);
> 
>  
> 
>  ;/**
> 
>  ;  Saves the current CPU context that can be restored with a call to LongJump() and returns 0.#
> 

Your git setup is wrong as well (what with the extra line breaks in the
formatted patch); please run "BaseTools/Scripts/SetupGit.py" in your
edk2 clone.

Updating the CC list on this one too.

Thanks
Laszlo