efi-boot-shim.git/load-options.c, branch rolling

Silence minor nit in load-options parsing debug output

2025-02-24T20:22:28+00:00

Previously when there were no load options, this would go in the debug log: load-options.c:313:parse_load_options() full load options: include/hexdump.h:92:vhexdumpf() hexdump of a NULL pointer! This changes it to say: load-options.c:315:parse_load_options() LoadOptions is empty Signed-off-by: Peter Jones

Add configuration option to boot an alternative 2nd stage

2025-02-06T20:13:23+00:00

Add the ability for shim to load an optional configuration file. This new file is called "options.csv". The configuration file is completely optional. If used, it is located in the same directory as the booted shim. The "options.csv" file currently allows a single entry. Other options could be added to it in the future. The first and only entry in the file is the name of the secondary boot loader shim will load. The "options.csv" file is in Unicode LE format. This allows a signed shim to directly load a UKI without the need to rename it to grub. Shim's transitive trust is maintained. If the alternative 2nd stage can not be verified, it will not boot. Signed-off-by: Eric Snowberg

shim: Allow data after the end of device path node in load options

2025-01-15T20:59:30+00:00

When looking for load option optional data, the parser asserts that the byte after the end of device path node is the same as what the file path length says it should be. While unusual, it is valid if the end of device path node comes before the end of the file path list. That supports some unusual Dell load options where there are two device paths in the list but the first is terminated by an End Entire Device Path. Maybe they intended to use an End Device Path Instance node there? Who knows. Either way, treating it as invalid ends up trying to read paths from the beginning of the option with obviously poor results. Fixes: #649 Signed-off-by: Dan Nicholson

Discard load-options that start with WINDOWS

2024-12-17T19:35:26+00:00

Windows bcdedit.exe creates boot entries where load options begin with "WINDOWS\0" (in 8-bit chars), followed by some Windows-specific data which is useless for shim. This data causes shim error "Failed to open \EFI\mypath\䥗䑎坏S". Resolves: #370 Signed-off-by: Lauri Kenttä

shim: don't set second_stage to the empty string

2024-05-08T21:01:58+00:00

When LoadOptions is either L" " or L"shim.efi ", parse_load_options sets second_stage to the empty string. This is unlikely to be what is intended, and typically leads to a non-obvious failure mode. The failure happens because parse_load_options's call to split_load_options (after eating shim's own filename, if present) returns the empty string. Since init_grub typically passes second_stage to start_image, this causes read_image to concatenate the empty string onto the directory name. This means PathName refers to the directory, not the path to a pe image. Then load_image successfully opens a handle on the directory and reads "data" from it. It only eventually fails when handle_image calls read_header which finds that this data isn't in fact a pe header, reporting "Invalid image". This scenario has been seen when shim is loaded via rEFInd 0.11.5, which sets LoadOptions to the name of the shim program followed by a space character. Instead, modify parse_load_options to leave second_stage set to its default value rather than the empty string. Signed-off-by: Jonathan Davies

Discard load-options that start with a NUL

2022-09-01T19:38:02+00:00

In 6c8d08c0af4768c715b79c8ec25141d56e34f8b4 ("shim: Ignore UEFI LoadOptions that are just NUL characters."), a check was added to discard load options that are entirely NUL. We now see some firmwares that start LoadOptions with a NUL, and then follow it with garbage (path to directory containing loaders). Widen the check to just discard anything that starts with a NUL. Resolves: #490 Related: #95 See-also: https://bugzilla.redhat.com/show_bug.cgi?id=2113005 Signed-off-by: Robbie Harwood

shim: Dump load options in verbose mode

2021-09-14T15:19:58+00:00

Dump the load options before parsing them so that we can see which things are failing to parse.

shim: don't fail on the odd LoadOptions length

2021-07-20T13:44:47+00:00

Some firmware feeds the LoadOptions with an odd length when booting from an USB device(*). We should only skip this kind of LoadOptions, not fail it, or the user won't be able to boot the system from USB or CD-ROM. (*) https://bugzilla.suse.com/show_bug.cgi?id=1185232#c62 Signed-off-by: Gary Lin

Add a tester for parse_load_options()

2021-07-20T13:44:25+00:00

This adds tests for all the cases we've documented in the set_second_stage() comments. Each test checks that all of second_stage, loader_str, and loader_str_size are set correctly. Note that this adds a dependency on libefivar to build device paths to test against. Signed-off-by: Peter Jones

shim: move the bulk of set_second_stage() to its own file

2021-07-20T13:44:25+00:00

This moves set_second_stage() and some of the helper functions it uses out of shim.c, so that it's easier to write test cases for. Signed-off-by: Peter Jones