From d8ac9d53b66a3a940962945c4102f1fcd644cde1 Mon Sep 17 00:00:00 2001 From: Leah Rowe Date: Sun, 27 Oct 2024 01:12:56 +0100 Subject: Switch Dell 3050 Micro to newer coreboot revision Specifically, use the same revision that Mate used in patchset 15. This will ensure that any issues are *not* caused by the coreboot revision; this is being done, because the old coreboot revision was from July, but patchset 15 from Mate is based on a September revision of coreboot. I've been eliminating as many variables as possible, trying to fix SeaBIOS payload on this machine, because it hangs in Libreboot, but not when building from gerrit directly, which means the coreboot revision may be a factor (since I'm using his patches on an older revision so upstream might have made some changes since then that the port relies on). For this, a new coreboot tree is used, called "dell7", referring to the fact that Kabylake is Intel's 7th generation. Signed-off-by: Leah Rowe --- config/submodule/coreboot/dell7/vboot/module.cfg | 3 + ...inuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch | 178 +++++++++++++++++++++ 2 files changed, 181 insertions(+) create mode 100644 config/submodule/coreboot/dell7/vboot/module.cfg create mode 100644 config/submodule/coreboot/dell7/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch (limited to 'config/submodule/coreboot/dell7/vboot') diff --git a/config/submodule/coreboot/dell7/vboot/module.cfg b/config/submodule/coreboot/dell7/vboot/module.cfg new file mode 100644 index 00000000..917d23fa --- /dev/null +++ b/config/submodule/coreboot/dell7/vboot/module.cfg @@ -0,0 +1,3 @@ +subrepo="https://review.coreboot.org/vboot.git" +subrepo_bkup="https://github.com/coreboot/vboot" +subhash="f1f70f46dc5482bb7c654e53ed58d4001e386df2" diff --git a/config/submodule/coreboot/dell7/vboot/patches/0001-extract_vmlinuz.c-Fix-the-bounds-check-on-vmlinuz_he.patch b/config/submodule/coreboot/dell7/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/dell7/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" +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 + -- cgit v1.2.1