SBAT: parse a copy of the table that's got a NUL at the end

Right now we allocate the PE file's contents in RW memory, but hopefully
that won't always be the case.  Our SBAT parsing, however, very much
expects to be able to edit it.  We also don't actually know that shim's
.sbat section is loaded r/w, so we can't necessarily write there.

This patch copies the SBAT data to its own buffer, plus one NUL byte at
the end, so we can always be sure that will work.

Signed-off-by: Peter Jones <pjones@redhat.com>

1 files changed, 13 insertions, 1 deletions

diff --git a/pe.c b/pe.c
index f3e93490..acbf82e8 100644
--- a/pe.c
+++ b/pe.c
@@ -1045,7 +1045,19 @@ handle_image (void *data, unsigned int datasize,
 		struct sbat_entry *entry = NULL;
 
 		if (SBATBase && SBATSize) {
-			res = parse_sbat(SBATBase, SBATSize, buffer, &sbat);
+			char *sbat_data;
+			size_t sbat_size;
+
+			sbat_size = SBATSize + 1;
+			sbat_data = AllocatePool(sbat_size);
+			if (!sbat_data) {
+				console_print(L"Failed to allocate SBAT buffer\n");
+				return EFI_OUT_OF_RESOURCES;
+			}
+			CopyMem(sbat_data, SBATBase, SBATSize);
+			sbat_data[SBATSize] = '\0';
+
+			res = parse_sbat(sbat_data, sbat_size, buffer, &sbat);
 			if (res < 0) {
 				console_print(L"SBAT data not correct: %r\n", res);
 				return EFI_UNSUPPORTED;