b05e585d49
Rusty had clearly not actually tested his module signing changes that I
(trustingly) applied as commit e2a666d52b ("kbuild: sign the modules
at install time"). That commit had multiple bugs:
- using "${#VARIABLE}" to get the number of characters in a shell
variable may look clever, but it's locale-dependent: it returns the
number of *characters*, not bytes. And we do need bytes.
So don't use "${#..}" expansion, do the stupid "wc -c" thing instead
(where "c" stands for "bytes", not "characters", despite the letter.
- Rusty had confused "siglen" and "signerlen", and his conversion
didn't set "signerlen" at all, and incorrectly set "siglen" to the
size of the signer, not the size of the signature.
End result: the modified sign-file script did create something that
superficially *looked* like a signature, but didn't actually work at
all, and would fail the signature check. Oops.
Tssk, tssk, Rusty.
But Rusty was definitely right that this whole thing should be rewritten
in perl by somebody who has the perl-fu to do so. That is not me,
though - I'm just doing an emergency fix for the shell script.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
109 lines
2.7 KiB
Bash
109 lines
2.7 KiB
Bash
#!/bin/bash
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#
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# Sign a module file using the given key.
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#
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# Format: sign-file <key> <x509> <keyid-script> <module>
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#
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scripts=`dirname $0`
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CONFIG_MODULE_SIG_SHA512=y
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if [ -r .config ]
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then
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. ./.config
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fi
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key="$1"
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x509="$2"
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keyid_script="$3"
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mod="$4"
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if [ ! -r "$key" ]
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then
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echo "Can't read private key" >&2
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exit 2
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fi
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if [ ! -r "$x509" ]
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then
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echo "Can't read X.509 certificate" >&2
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exit 2
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fi
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#
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# Signature parameters
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#
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algo=1 # Public-key crypto algorithm: RSA
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hash= # Digest algorithm
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id_type=1 # Identifier type: X.509
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#
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# Digest the data
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#
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dgst=
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if [ "$CONFIG_MODULE_SIG_SHA1" = "y" ]
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then
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prologue="0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2B, 0x0E, 0x03, 0x02, 0x1A, 0x05, 0x00, 0x04, 0x14"
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dgst=-sha1
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hash=2
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elif [ "$CONFIG_MODULE_SIG_SHA224" = "y" ]
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then
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prologue="0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, 0x05, 0x00, 0x04, 0x1C"
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dgst=-sha224
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hash=7
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elif [ "$CONFIG_MODULE_SIG_SHA256" = "y" ]
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then
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prologue="0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20"
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dgst=-sha256
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hash=4
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elif [ "$CONFIG_MODULE_SIG_SHA384" = "y" ]
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then
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prologue="0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, 0x05, 0x00, 0x04, 0x30"
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dgst=-sha384
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hash=5
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elif [ "$CONFIG_MODULE_SIG_SHA512" = "y" ]
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then
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prologue="0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40"
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dgst=-sha512
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hash=6
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else
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echo "$0: Can't determine hash algorithm" >&2
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exit 2
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fi
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(
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perl -e "binmode STDOUT; print pack(\"C*\", $prologue)" || exit $?
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openssl dgst $dgst -binary $mod || exit $?
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) >$mod.dig || exit $?
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#
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# Generate the binary signature, which will be just the integer that comprises
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# the signature with no metadata attached.
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#
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openssl rsautl -sign -inkey $key -keyform PEM -in $mod.dig -out $mod.sig || exit $?
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siglen=`stat -c %s $mod.sig`
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SIGNER="`perl $keyid_script $x509 signer-name`"
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KEYID="`perl $keyid_script $x509 keyid`"
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keyidlen=$(echo -n "$KEYID" | wc -c)
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signerlen=$(echo -n "$SIGNER" | wc -c)
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#
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# Build the signed binary
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#
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(
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cat $mod || exit $?
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echo '~Module signature appended~' || exit $?
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echo -n "$SIGNER" || exit $?
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echo -n "$KEYID" || exit $?
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# Preface each signature integer with a 2-byte BE length
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perl -e "binmode STDOUT; print pack(\"n\", $siglen)" || exit $?
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cat $mod.sig || exit $?
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# Generate the information block
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perl -e "binmode STDOUT; print pack(\"CCCCCxxxN\", $algo, $hash, $id_type, $signerlen, $keyidlen, $siglen + 2)" || exit $?
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) >$mod~ || exit $?
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mv $mod~ $mod || exit $?
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