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https://git.proxmox.com/git/efi-boot-shim
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The previous strategy is to locate the first available PXE_BASE_CODE protocol and to fetch the second stage image from it, and this may cause shim to fetch the wrong second stage image, i.e. grub.efi. Consider the machine with the following boot order: 1. PXE Boot 2. Hard Drive Assume that the EFI image, e.g. bootx64.efi, in the PXE server is broken, then "PXE Boot" will fail and fallback to "Hard Drive". While shim.efi in "Hard Drive" is loaded, it will find the PXE protocol is available and fetch grub.efi from the PXE server, not grub.efi in the disk. This commit checks the DeviceHandle from Loaded Image. If the device supports PXE, then shim fetches grub.efi with the PXE protocol. Otherwise, shim loads grub.efi from the disk. Signed-off-by: Gary Ching-Pang Lin <glin@suse.com> |
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|---|---|---|
| Cryptlib | ||
| include | ||
| lib | ||
| .gitignore | ||
| cert.S | ||
| COPYRIGHT | ||
| crypt_blowfish.c | ||
| crypt_blowfish.h | ||
| elf_ia32_efi.lds | ||
| elf_ia64_efi.lds | ||
| elf_x86_64_efi.lds | ||
| fallback.c | ||
| make-certs | ||
| Makefile | ||
| MokManager.c | ||
| MokVars.txt | ||
| netboot.c | ||
| netboot.h | ||
| PasswordCrypt.c | ||
| PasswordCrypt.h | ||
| README | ||
| replacements.c | ||
| replacements.h | ||
| shim.c | ||
| shim.h | ||
| testplan.txt | ||
| TODO | ||
| ucs2.h | ||
| 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. To use shim, simply place a hex dump of the public certificate in cert.h and build it with make.