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authorLuke T. Shumaker <lukeshu@lukeshu.com>2024-05-30 14:15:06 -0600
committerLuke T. Shumaker <lukeshu@lukeshu.com>2024-05-30 17:40:37 -0600
commit221206b4da6e6e8e3d2782f3903956e55299be40 (patch)
tree4e469090dcb71ac217ed673a11a7962c29fc3392 /config/submodule/coreboot/coreboot413/vboot
parent7fbcb7be95eb5bed42f0656015228352aa0882af (diff)
Fix building vboot on i686
Diffstat (limited to 'config/submodule/coreboot/coreboot413/vboot')
-rw-r--r--config/submodule/coreboot/coreboot413/vboot/patches/0001-don-t-treat-warnings-as-errors.patch26
-rw-r--r--config/submodule/coreboot/coreboot413/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch178
2 files changed, 178 insertions, 26 deletions
diff --git a/config/submodule/coreboot/coreboot413/vboot/patches/0001-don-t-treat-warnings-as-errors.patch b/config/submodule/coreboot/coreboot413/vboot/patches/0001-don-t-treat-warnings-as-errors.patch
deleted file mode 100644
index eb491a37..00000000
--- a/config/submodule/coreboot/coreboot413/vboot/patches/0001-don-t-treat-warnings-as-errors.patch
+++ /dev/null
@@ -1,26 +0,0 @@
-From 49569081d248e6eea3d4fb8a2cfb70154d9fd91f Mon Sep 17 00:00:00 2001
-From: Leah Rowe <info@minifree.org>
-Date: Tue, 21 May 2024 23:14:51 +0100
-Subject: [PATCH 1/1] don't treat warnings as errors
-
-Signed-off-by: Leah Rowe <info@minifree.org>
----
- Makefile | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
-diff --git a/Makefile b/Makefile
-index 8f1bd148..67a282ee 100644
---- a/Makefile
-+++ b/Makefile
-@@ -124,7 +124,7 @@ endif
- # Provide default CC and CFLAGS for firmware builds; if you have any -D flags,
- # please add them after this point (e.g., -DVBOOT_DEBUG).
- DEBUG_FLAGS := $(if ${DEBUG},-g -O0,-g -Os)
--WERROR := -Werror
-+WERROR := -Wno-error -w
- FIRMWARE_FLAGS := -nostdinc -ffreestanding -fno-builtin -fno-stack-protector
- COMMON_FLAGS := -pipe ${WERROR} -Wall -Wstrict-prototypes -Wtype-limits \
- -Wundef -Wmissing-prototypes -Wno-trigraphs -Wredundant-decls -Wshadow \
---
-2.39.2
-
diff --git a/config/submodule/coreboot/coreboot413/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch b/config/submodule/coreboot/coreboot413/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch
new file mode 100644
index 00000000..1ac41de6
--- /dev/null
+++ b/config/submodule/coreboot/coreboot413/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch
@@ -0,0 +1,178 @@
+From 195f61375aeec9eec16604ec59f6eda2e6058cc1 Mon Sep 17 00:00:00 2001
+From: "Luke T. Shumaker" <lukeshu@lukeshu.com>
+Date: Thu, 30 May 2024 14:08:33 -0600
+Subject: [PATCH 1/1] extract_vmlinuz.c: Fix the bounds check on
+ vmlinuz_header_{offset,size}
+
+The check on vmlinuz_header_offset and vmlinuz_header_size is obviously
+wrong:
+
+ if (!vmlinuz_header_size ||
+ kpart_data + vmlinuz_header_offset + vmlinuz_header_size >
+ kpart_data) {
+ return 1;
+ }
+
+`kpart_data + some_unsigned_values` can obviously never be `> kpart_data`,
+unless something has overflowed! And `vmlinuz_header_offset` hasn't even
+been set yet (besides being initialized to zero)!
+
+GCC will deduce that if the check didn't cause the function to bail, then
+vmlinuz_header_size (a uint32_t) must be "negative"; that is: in the range
+[2GiB,4GiB).
+
+On platforms where size_t is 32-bits, this is *especially* broken.
+memcpy's size argument must be in the range [0,2GiB). Because GCC has
+proved that vmlinuz_header_size is higher than that, it will fail to
+compile:
+
+ host/lib/extract_vmlinuz.c:67:9: error: 'memcpy' specified bound between 2147483648 and 4294967295 exceeds maximum object size 2147483647 [-Werror=stringop-overflow=]
+
+So, fix the check.
+
+I can now say that what I suspect the original author meant to write would
+be the following patch, if `vmlinuz_header_offset` were already set:
+
+ -kpart_data + vmlinuz_header_offset + vmlinuz_header_size > kpart_data
+ +now + vmlinuz_header_offset + vmlinuz_header_size > kpart_size
+
+This hypothesis is supported by `now` not getting incremented by
+`kblob_size` the way it is for the keyblock and preamble sizes.
+
+However, we can also see that even this "corrected" bounds check is
+insufficient: it does not detect the vmlinuz_header overflowing into
+kblob_data.
+
+OK, so let's describe the fix:
+
+Have a `*vmlinuz_header` pointer instead of a
+`uint64_t vmlinuz_header_offset`, to be more similar to all the other
+regions. With this change, the correct check becomes a simple
+
+ vmlinuz_header + vmlinuz_header_size > kblob_data
+
+While we're at it, make some changes that could have helped avoid this in
+the first place:
+
+ - Add comments.
+ - Calculate the vmlinuz_header offset right away, instead of waiting.
+ - Go ahead and increment `now` by `kblob_size`, to increase regularity.
+
+Change-Id: I5c03e49070b6dd2e04459566ef7dd129d27736e4
+---
+ host/lib/extract_vmlinuz.c | 72 +++++++++++++++++++++++++++-----------
+ 1 file changed, 51 insertions(+), 21 deletions(-)
+
+diff --git a/host/lib/extract_vmlinuz.c b/host/lib/extract_vmlinuz.c
+index 4ccfcf33..d2c09443 100644
+--- a/host/lib/extract_vmlinuz.c
++++ b/host/lib/extract_vmlinuz.c
+@@ -15,16 +15,44 @@
+
+ int ExtractVmlinuz(void *kpart_data, size_t kpart_size,
+ void **vmlinuz_out, size_t *vmlinuz_size) {
++ // We're going to be extracting `vmlinuz_header` and
++ // `kblob_data`, and returning the concatenation of them.
++ //
++ // kpart_data = +-[kpart_size]------------------------------------+
++ // | |
++ // keyblock = | +-[keyblock->keyblock_size]-------------------+ |
++ // | | struct vb2_keyblock keyblock | |
++ // | | char [] ...data... | |
++ // | +---------------------------------------------+ |
++ // | |
++ // preamble = | +-[preamble->preamble_size]-------------------+ |
++ // | | struct vb2_kernel_preamble preamble | |
++ // | | char [] ...data... | |
++ // | | char [] vmlinuz_header | |
++ // | | char [] ...data... | |
++ // | +---------------------------------------------+ |
++ // | |
++ // kblob_data= | +-[preamble->body_signature.data_size]--------+ |
++ // | | char [] ...data... | |
++ // | +---------------------------------------------+ |
++ // | |
++ // +-------------------------------------------------+
++
+ size_t now = 0;
++ // The 3 sections of kpart_data.
++ struct vb2_keyblock *keyblock = NULL;
+ struct vb2_kernel_preamble *preamble = NULL;
+ uint8_t *kblob_data = NULL;
+ uint32_t kblob_size = 0;
++ // vmlinuz_header
++ uint8_t *vmlinuz_header = NULL;
+ uint32_t vmlinuz_header_size = 0;
+- uint64_t vmlinuz_header_address = 0;
+- uint64_t vmlinuz_header_offset = 0;
++ // The concatenated result.
+ void *vmlinuz = NULL;
+
+- struct vb2_keyblock *keyblock = (struct vb2_keyblock *)kpart_data;
++ // Isolate the 3 sections of kpart_data.
++
++ keyblock = (struct vb2_keyblock *)kpart_data;
+ now += keyblock->keyblock_size;
+ if (now > kpart_size)
+ return 1;
+@@ -36,37 +64,39 @@ int ExtractVmlinuz(void *kpart_data, size_t kpart_size,
+
+ kblob_data = kpart_data + now;
+ kblob_size = preamble->body_signature.data_size;
+-
+- if (!kblob_data || (now + kblob_size) > kpart_size)
++ now += kblob_size;
++ if (now > kpart_size)
+ return 1;
+
++ // Find `vmlinuz_header` within `preamble`.
++
+ if (preamble->header_version_minor > 0) {
+- vmlinuz_header_address = preamble->vmlinuz_header_address;
++ // calculate the vmlinuz_header offset from
++ // the beginning of the kpart_data. The kblob doesn't
++ // include the body_load_offset, but does include
++ // the keyblock and preamble sections.
++ size_t vmlinuz_header_offset =
++ preamble->vmlinuz_header_address -
++ preamble->body_load_address +
++ keyblock->keyblock_size +
++ preamble->preamble_size;
++
++ vmlinuz_header = kpart_data + vmlinuz_header_offset;
+ vmlinuz_header_size = preamble->vmlinuz_header_size;
+ }
+
+- if (!vmlinuz_header_size ||
+- kpart_data + vmlinuz_header_offset + vmlinuz_header_size >
+- kpart_data) {
++ if (!vmlinuz_header ||
++ !vmlinuz_header_size ||
++ vmlinuz_header + vmlinuz_header_size > kblob_data) {
+ return 1;
+ }
+
+- // calculate the vmlinuz_header offset from
+- // the beginning of the kpart_data. The kblob doesn't
+- // include the body_load_offset, but does include
+- // the keyblock and preamble sections.
+- vmlinuz_header_offset = vmlinuz_header_address -
+- preamble->body_load_address +
+- keyblock->keyblock_size +
+- preamble->preamble_size;
++ // Concatenate and return.
+
+ vmlinuz = malloc(vmlinuz_header_size + kblob_size);
+ if (vmlinuz == NULL)
+ return 1;
+-
+- memcpy(vmlinuz, kpart_data + vmlinuz_header_offset,
+- vmlinuz_header_size);
+-
++ memcpy(vmlinuz, vmlinuz_header, vmlinuz_header_size);
+ memcpy(vmlinuz + vmlinuz_header_size, kblob_data, kblob_size);
+
+ *vmlinuz_out = vmlinuz;
+--
+2.45.1
+