mirror of
https://git.proxmox.com/git/efi-boot-shim
synced 2025-08-03 18:51:49 +00:00
64a18c4ea6
When I modified the hexdumper to help debug MokListRT mirroring not
working because of PcdMaxVolatileVariableSize being tiny, I
inadvertently added something that is effectively:
hexdump(..., char *buf, ..., int position)
{
unsigned long begin = (position % 16);
unsigned long i;
...
for (i = 0; i < begin; i++) {
...
}
...
}
Unfortunately, in c if 0x8 is set in position, that means begin is
0xfffffffffffff8, because signed integer math is horrifying:
include/hexdump.h:99:vhexdumpf() &data[offset]:0x9E77E6BC size-offset:0x14
include/hexdump.h:15:prepare_hex() position:0x9E77E6BC
include/hexdump.h:17:prepare_hex() before:0xFFFFFFFFFFFFFFFC size:0x14
include/hexdump.h:19:prepare_hex() before:0xFFFFFFFFFFFFFFFC after:0x0
include/hexdump.h:21:prepare_hex() buf:0x000000009E77E2BC offset:0 &buf[offset]:0x000000009E77E2BC
Woops.
This could further have been prevented in /some/ cases by simply not
preparing the hexdump buffer when "verbose" is disabled.
This patch makes "pos" be unsigned in all cases, and also checks for
verbose in vhexdumpf() and simply returns if it is 0.
Signed-off-by: Peter Jones <pjones@redhat.com>
|
||
|---|---|---|
| Cryptlib | ||
| include | ||
| lib | ||
| .gitignore | ||
| .syntastic_c_config | ||
| .travis.yml | ||
| buildid.c | ||
| BUILDING | ||
| cert.S | ||
| COPYRIGHT | ||
| crypt_blowfish.c | ||
| elf_aarch64_efi.lds | ||
| elf_arm_efi.lds | ||
| elf_ia32_efi.lds | ||
| elf_ia64_efi.lds | ||
| elf_x86_64_efi.lds | ||
| errlog.c | ||
| fallback.c | ||
| httpboot.c | ||
| make-certs | ||
| Make.coverity | ||
| Make.defaults | ||
| Make.rules | ||
| Make.scan-build | ||
| Makefile | ||
| model.c | ||
| mok.c | ||
| MokManager.c | ||
| MokVars.txt | ||
| netboot.c | ||
| PasswordCrypt.c | ||
| README | ||
| README.fallback | ||
| README.tpm | ||
| replacements.c | ||
| shim.c | ||
| shim.h | ||
| testplan.txt | ||
| TODO | ||
| tpm.c | ||
| travis-build.sh | ||
| version.c.in | ||
| version.h | ||
shim is a trivial EFI application that, when run, attempts to open and execute another application. It will initially attempt to do this via the standard EFI LoadImage() and StartImage() calls. If these fail (because secure boot is enabled and the binary is not signed with an appropriate key, for instance) it will then validate the binary against a built-in certificate. If this succeeds and if the binary or signing key are not blacklisted then shim will relocate and execute the binary. shim will also install a protocol which permits the second-stage bootloader to perform similar binary validation. This protocol has a GUID as described in the shim.h header file and provides a single entry point. On 64-bit systems this entry point expects to be called with SysV ABI rather than MSABI, and so calls to it should not be wrapped. On systems with a TPM chip enabled and supported by the system firmware, shim will extend various PCRs with the digests of the targets it is loading. A full list is in the file README.tpm . To use shim, simply place a DER-encoded public certificate in a file such as pub.cer and build with "make VENDOR_CERT_FILE=pub.cer". There are a couple of build options, and a couple of ways to customize the build, described in BUILDING.