If the size of the supplied buffer in FileHandleReadLine(), module UefiFileHandleLib.c, was not 0, but was not enough to fit in the line, the size is increased, and then the Buffer of the new size is zeroed. This size is always larger than the supplied buffer size, causing supplied buffer overrun. Fix the issue by using the supplied buffer size in ZeroMem().
Signed-off-by: Vladimir Olovyannikov <vladimir.olovyanni...@broadcom.com> Cc: Michael D Kinney <michael.d.kin...@intel.com> Cc: Liming Gao <liming....@intel.com> Cc: Zhiguang Liu <zhiguang....@intel.com> --- MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c index 28e28e5f67d5..ab34e6ccd5f4 100644 --- a/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c +++ b/MdePkg/Library/UefiFileHandleLib/UefiFileHandleLib.c @@ -969,6 +969,7 @@ FileHandleReadLine( UINTN CharSize; UINTN CountSoFar; UINTN CrCount; + UINTN OldSize; UINT64 OriginalFilePosition; if (Handle == NULL @@ -1039,10 +1040,11 @@ FileHandleReadLine( // if we ran out of space tell when... // if ((CountSoFar+1-CrCount)*sizeof(CHAR16) > *Size){ + OldSize = *Size; *Size = (CountSoFar+1-CrCount)*sizeof(CHAR16); if (!Truncate) { - if (Buffer != NULL && *Size != 0) { - ZeroMem(Buffer, *Size); + if (Buffer != NULL && OldSize != 0) { + ZeroMem(Buffer, OldSize); } FileHandleSetPosition(Handle, OriginalFilePosition); return (EFI_BUFFER_TOO_SMALL); -- 2.26.2.266.ge870325ee8 -=-=-=-=-=-=-=-=-=-=-=- Groups.io Links: You receive all messages sent to this group. View/Reply Online (#61938): https://edk2.groups.io/g/devel/message/61938 Mute This Topic: https://groups.io/mt/75251007/21656 Group Owner: devel+ow...@edk2.groups.io Unsubscribe: https://edk2.groups.io/g/devel/unsub [arch...@mail-archive.com] -=-=-=-=-=-=-=-=-=-=-=-