How to get the position of LUKS header by `bgrep`
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I tried to get the position of LUKS header:
grep -a -b -P --only-matching 'LUKSxbaxbe' /dev/sdb
It is out of memory.
Some sugest me use 'bgrep' instead, but I don't how to make it work.
bgrep -A 20 'LUKSxbaxbe' /dev/sda./bgrep: invalid 2-hex-digit byte value: 'LU'
So how to make this work?
grep luks
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
add a comment |
I tried to get the position of LUKS header:
grep -a -b -P --only-matching 'LUKSxbaxbe' /dev/sdb
It is out of memory.
Some sugest me use 'bgrep' instead, but I don't how to make it work.
bgrep -A 20 'LUKSxbaxbe' /dev/sda./bgrep: invalid 2-hex-digit byte value: 'LU'
So how to make this work?
grep luks
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
add a comment |
I tried to get the position of LUKS header:
grep -a -b -P --only-matching 'LUKSxbaxbe' /dev/sdb
It is out of memory.
Some sugest me use 'bgrep' instead, but I don't how to make it work.
bgrep -A 20 'LUKSxbaxbe' /dev/sda./bgrep: invalid 2-hex-digit byte value: 'LU'
So how to make this work?
grep luks
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
I tried to get the position of LUKS header:
grep -a -b -P --only-matching 'LUKSxbaxbe' /dev/sdb
It is out of memory.
Some sugest me use 'bgrep' instead, but I don't how to make it work.
bgrep -A 20 'LUKSxbaxbe' /dev/sda./bgrep: invalid 2-hex-digit byte value: 'LU'
So how to make this work?
grep luks
grep luks
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
asked Mar 10 at 11:10
MaggicmuojetMaggicmuojet
113
113
add a comment |
add a comment |
1 Answer
1
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grep tends to run out of memory since it reads until end-of-line, but in binary data there might not be an end-of-line for a long time. You could still use grep by grepping chunks of smaller-than-memory size, roughly:
# dd bs=1M iflag=fullblock if=/dev/sdb skip=X count=Y | grep ...
Rinse and repeat for all chunks. If you're not sure about whether the data will be aligned properly, make the chunks overlap some (next X=X+Y-1).
Alternatively, strings would probably avoid the running out of memory part (very long lines of printable ASCII are unlikely to appear). Then you have a list of offsets to check. These can be false matches since strings excludes the xbaxbe part.
# strings -t d -n 4 /dev/sdb | grep 'LUKS$'
11534336 LUKS
23068672 LUKS
34603008 LUKS
# losetup --find --show --offset=23068672 /dev/sdb
/dev/loop9
# cryptsetup luksDump /dev/loop9
Tools like testdisk or binwalk (with a custom magic signature) might be able to locate LUKS headers more efficiently. But for a quick hack, strings usually works well enough.
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
No,strings -t d -n 4 /dev/sdb | grep LUKSlists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?
– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.grep -B 1 xts-plain(for luks1 headers, for luks2 you wantstrings -t d -n 100 | grep '"type":"luks2"'and substract 4096).
– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdbThen a message:Binary file /dev/sdb matches
– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb tostrings -t d -n 100 | grep '"type":"luks2"'?
– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
|
show 1 more comment
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1 Answer
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1 Answer
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grep tends to run out of memory since it reads until end-of-line, but in binary data there might not be an end-of-line for a long time. You could still use grep by grepping chunks of smaller-than-memory size, roughly:
# dd bs=1M iflag=fullblock if=/dev/sdb skip=X count=Y | grep ...
Rinse and repeat for all chunks. If you're not sure about whether the data will be aligned properly, make the chunks overlap some (next X=X+Y-1).
Alternatively, strings would probably avoid the running out of memory part (very long lines of printable ASCII are unlikely to appear). Then you have a list of offsets to check. These can be false matches since strings excludes the xbaxbe part.
# strings -t d -n 4 /dev/sdb | grep 'LUKS$'
11534336 LUKS
23068672 LUKS
34603008 LUKS
# losetup --find --show --offset=23068672 /dev/sdb
/dev/loop9
# cryptsetup luksDump /dev/loop9
Tools like testdisk or binwalk (with a custom magic signature) might be able to locate LUKS headers more efficiently. But for a quick hack, strings usually works well enough.
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
No,strings -t d -n 4 /dev/sdb | grep LUKSlists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?
– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.grep -B 1 xts-plain(for luks1 headers, for luks2 you wantstrings -t d -n 100 | grep '"type":"luks2"'and substract 4096).
– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdbThen a message:Binary file /dev/sdb matches
– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb tostrings -t d -n 100 | grep '"type":"luks2"'?
– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
|
show 1 more comment
grep tends to run out of memory since it reads until end-of-line, but in binary data there might not be an end-of-line for a long time. You could still use grep by grepping chunks of smaller-than-memory size, roughly:
# dd bs=1M iflag=fullblock if=/dev/sdb skip=X count=Y | grep ...
Rinse and repeat for all chunks. If you're not sure about whether the data will be aligned properly, make the chunks overlap some (next X=X+Y-1).
Alternatively, strings would probably avoid the running out of memory part (very long lines of printable ASCII are unlikely to appear). Then you have a list of offsets to check. These can be false matches since strings excludes the xbaxbe part.
# strings -t d -n 4 /dev/sdb | grep 'LUKS$'
11534336 LUKS
23068672 LUKS
34603008 LUKS
# losetup --find --show --offset=23068672 /dev/sdb
/dev/loop9
# cryptsetup luksDump /dev/loop9
Tools like testdisk or binwalk (with a custom magic signature) might be able to locate LUKS headers more efficiently. But for a quick hack, strings usually works well enough.
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
No,strings -t d -n 4 /dev/sdb | grep LUKSlists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?
– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.grep -B 1 xts-plain(for luks1 headers, for luks2 you wantstrings -t d -n 100 | grep '"type":"luks2"'and substract 4096).
– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdbThen a message:Binary file /dev/sdb matches
– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb tostrings -t d -n 100 | grep '"type":"luks2"'?
– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
|
show 1 more comment
grep tends to run out of memory since it reads until end-of-line, but in binary data there might not be an end-of-line for a long time. You could still use grep by grepping chunks of smaller-than-memory size, roughly:
# dd bs=1M iflag=fullblock if=/dev/sdb skip=X count=Y | grep ...
Rinse and repeat for all chunks. If you're not sure about whether the data will be aligned properly, make the chunks overlap some (next X=X+Y-1).
Alternatively, strings would probably avoid the running out of memory part (very long lines of printable ASCII are unlikely to appear). Then you have a list of offsets to check. These can be false matches since strings excludes the xbaxbe part.
# strings -t d -n 4 /dev/sdb | grep 'LUKS$'
11534336 LUKS
23068672 LUKS
34603008 LUKS
# losetup --find --show --offset=23068672 /dev/sdb
/dev/loop9
# cryptsetup luksDump /dev/loop9
Tools like testdisk or binwalk (with a custom magic signature) might be able to locate LUKS headers more efficiently. But for a quick hack, strings usually works well enough.
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
grep tends to run out of memory since it reads until end-of-line, but in binary data there might not be an end-of-line for a long time. You could still use grep by grepping chunks of smaller-than-memory size, roughly:
# dd bs=1M iflag=fullblock if=/dev/sdb skip=X count=Y | grep ...
Rinse and repeat for all chunks. If you're not sure about whether the data will be aligned properly, make the chunks overlap some (next X=X+Y-1).
Alternatively, strings would probably avoid the running out of memory part (very long lines of printable ASCII are unlikely to appear). Then you have a list of offsets to check. These can be false matches since strings excludes the xbaxbe part.
# strings -t d -n 4 /dev/sdb | grep 'LUKS$'
11534336 LUKS
23068672 LUKS
34603008 LUKS
# losetup --find --show --offset=23068672 /dev/sdb
/dev/loop9
# cryptsetup luksDump /dev/loop9
Tools like testdisk or binwalk (with a custom magic signature) might be able to locate LUKS headers more efficiently. But for a quick hack, strings usually works well enough.
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
edited Mar 15 at 18:21
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
answered Mar 10 at 11:47
frostschutzfrostschutz
27.7k15790
27.7k15790
No,strings -t d -n 4 /dev/sdb | grep LUKSlists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?
– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.grep -B 1 xts-plain(for luks1 headers, for luks2 you wantstrings -t d -n 100 | grep '"type":"luks2"'and substract 4096).
– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdbThen a message:Binary file /dev/sdb matches
– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb tostrings -t d -n 100 | grep '"type":"luks2"'?
– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
|
show 1 more comment
No,strings -t d -n 4 /dev/sdb | grep LUKSlists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?
– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.grep -B 1 xts-plain(for luks1 headers, for luks2 you wantstrings -t d -n 100 | grep '"type":"luks2"'and substract 4096).
– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdbThen a message:Binary file /dev/sdb matches
– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb tostrings -t d -n 100 | grep '"type":"luks2"'?
– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
No,
strings -t d -n 4 /dev/sdb | grep LUKS lists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?– Maggicmuojet
Mar 11 at 7:52
No,
strings -t d -n 4 /dev/sdb | grep LUKS lists too many iterms about LUKS even out of the number Terminal window can contain, how can I make it print only LUKS header for LUKS partition?– Maggicmuojet
Mar 11 at 7:52
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.
grep -B 1 xts-plain (for luks1 headers, for luks2 you want strings -t d -n 100 | grep '"type":"luks2"' and substract 4096).– frostschutz
Mar 11 at 9:24
@Maggicmuojet Not really possible with strings... Terminal window? Redirect output to a file, and script it. Otherwise, if you're sure about the cipher, you could also e.g.
grep -B 1 xts-plain (for luks1 headers, for luks2 you want strings -t d -n 100 | grep '"type":"luks2"' and substract 4096).– frostschutz
Mar 11 at 9:24
sudo grep -B 1 xts-plain /dev/sdb Then a message: Binary file /dev/sdb matches– Maggicmuojet
Mar 12 at 12:42
sudo grep -B 1 xts-plain /dev/sdb Then a message: Binary file /dev/sdb matches– Maggicmuojet
Mar 12 at 12:42
Where to bit /dev/sdb to
strings -t d -n 100 | grep '"type":"luks2"'?– Maggicmuojet
Mar 12 at 12:44
Where to bit /dev/sdb to
strings -t d -n 100 | grep '"type":"luks2"'?– Maggicmuojet
Mar 12 at 12:44
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
Is there any1 in, and any1 help?
– Maggicmuojet
Mar 14 at 5:55
|
show 1 more comment
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