Date: Sat, 28 Dec 2019 23:46:00 -0600 From: Clay Daniels <clay.daniels.jr@gmail.com> To: "freebsd-questions@freebsd.org" <freebsd-questions@freebsd.org> Subject: Reading nvram efi variables Message-ID: <CAGLDxTUZoXhWHFXBy4qoYjWPUk%2B3nf%2Bp1xpk1U6mU80=5Y4Z_g@mail.gmail.com>
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The efivar command will list efi variables using: # efivar -l ~ 8be4df61-93ca-11d2-aa0d-00e098032b8c-dbxDefault 8be4df61-93ca-11d2-aa0d-00e098032b8c-dbDefault 8be4df61-93ca-11d2-aa0d-00e098032b8c-KEKDefault 8be4df61-93ca-11d2-aa0d-00e098032b8c-PKDefault ~ (There are a lot more but these secure boot keys are the ones of interest to me) I can write them to a file with: # efivar -n 8be4df61-93ca-11d2-aa0d-00e098032b8c-dbxDefault > dbx I can sort of read it with hexdump: root@bsd13:/bootkeys # hexdump -C dbx 00000000 38 62 65 34 64 66 36 31 2d 39 33 63 61 2d 31 31 |8be4df61-93ca-11| 00000010 64 32 2d 61 61 30 64 2d 30 30 65 30 39 38 30 33 |d2-aa0d-00e09803| 00000020 32 62 38 63 2d 64 62 78 44 65 66 61 75 6c 74 0a |2b8c-dbxDefault.| 00000030 30 30 30 30 3a 20 32 36 20 31 36 20 63 34 20 63 |0000: 26 16 c4 c| 00000040 31 20 34 63 20 35 30 20 39 32 20 34 30 20 61 63 |1 4c 50 92 40 ac| 00000050 20 61 39 20 34 31 20 66 39 20 33 36 20 39 33 20 | a9 41 f9 36 93 | 00000060 34 33 20 32 38 20 0a 30 30 31 30 3a 20 38 63 20 |43 28 .0010: 8c | 00000070 30 65 20 30 30 20 30 30 20 30 30 20 30 30 20 30 |0e 00 00 00 00 0| 00000080 30 20 30 30 20 33 30 20 30 30 20 30 30 20 30 30 |0 00 30 00 00 00| 00000090 20 62 64 20 39 61 20 66 61 20 37 37 20 0a 30 30 | bd 9a fa 77 .00| 000000a0 32 30 3a 20 35 39 20 30 33 20 33 32 20 34 64 20 |20: 59 03 32 4d | 000000b0 62 64 20 36 30 20 32 38 20 66 34 20 65 37 20 38 |bd 60 28 f4 e7 8| 000000c0 66 20 37 38 20 34 62 20 38 30 20 62 34 20 64 39 |f 78 4b 80 b4 d9| 000000d0 20 36 39 20 0a 30 30 33 30 3a 20 33 31 20 62 66 | 69 .0030: 31 bf| 000000e0 20 30 64 20 30 32 20 66 64 20 39 31 20 61 36 20 | 0d 02 fd 91 a6 | 000000f0 31 65 20 31 39 20 64 31 20 34 66 20 31 64 20 61 |1e 19 d1 4f 1d a| 00000100 34 20 35 32 20 65 36 20 36 64 20 0a 30 30 34 30 |4 52 e6 6d .0040| 00000110 3a 20 62 32 20 34 30 20 38 63 20 61 38 20 36 30 |: b2 40 8c a8 60| 00000120 20 34 64 20 34 31 20 31 66 20 39 32 20 36 35 20 | 4d 41 1f 92 65 | 00000130 39 66 20 30 61 20 62 64 20 39 61 20 66 61 20 37 |9f 0a bd 9a fa 7| 00000140 37 20 0a 30 30 35 30 3a 20 35 39 20 30 33 20 33 |7 .0050: 59 03 3| 00000150 32 20 34 64 20 62 64 20 36 30 20 32 38 20 66 34 |2 4d bd 60 28 f4| 00000160 20 65 37 20 38 66 20 37 38 20 34 62 20 66 35 20 | e7 8f 78 4b f5 | 00000170 32 66 20 38 33 20 61 33 20 0a 30 30 36 30 3a 20 |2f 83 a3 .0060: | 00000180 66 61 20 39 63 20 66 62 20 64 36 20 39 32 20 30 |fa 9c fb d6 92 0| 00000190 66 20 37 32 20 32 38 20 32 34 20 64 62 20 65 34 |f 72 28 24 db e4| 000001a0 20 30 33 20 34 35 20 33 34 20 64 32 20 35 62 20 | 03 45 34 d2 5b | 000001b0 0a 30 30 37 30 3a 20 38 35 20 30 37 20 32 34 20 |.0070: 85 07 24 | 000001c0 36 62 20 33 62 20 39 35 20 37 64 20 61 63 20 36 |6b 3b 95 7d ac 6| 000001d0 65 20 31 62 20 63 65 20 37 61 20 62 64 20 39 61 |e 1b ce 7a bd 9a| 000001e0 20 66 61 20 37 37 20 0a 30 30 38 30 3a 20 35 39 | fa 77 .0080: 59| 000001f0 20 30 33 20 33 32 20 34 64 20 62 64 20 36 30 20 | 03 32 4d bd 60 | 00000200 32 38 20 66 34 20 65 37 20 38 66 20 37 38 20 34 |28 f4 e7 8f 78 4| ~ 00003300 63 20 37 38 20 39 30 20 31 64 20 33 66 20 62 33 |c 78 90 1d 3f b3| 00003310 20 33 37 20 33 38 20 37 36 20 0a 30 65 64 30 3a | 37 38 76 .0ed0:| 00003320 20 38 35 20 31 31 20 61 33 20 30 36 20 31 37 20 | 85 11 a3 06 17 | 00003330 61 66 20 61 30 20 31 64 20 0a 0a |af a0 1d ..| 0000333b root@bsd13:/bootkeys # Does anyone have a way to get any more real information out of these files in more humanly readable form? Clay
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