(Tcl) Validate a .pkpass Archive

Opens a .pkpass archive (which is just a .zip renamed to .pkpass) and validates the contents. The hashes in the manifest are compared with the computed hash values for each individual file. If all computed hash values match, then the signature is verified.

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load ./chilkat.dll

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

set crypt [new_CkCrypt2]

set zip [new_CkZip]

set success [CkZip_OpenZip $zip "qa_data/pkpass/invalid.pkpass"]
if {$success == 0} then {
    puts [CkZip_lastErrorText $zip]
    delete_CkCrypt2 $crypt
    delete_CkZip $zip
    exit
}

# Get the contents of the manifest.json file, which contains something like this:

# {
#   "icon.png" : "0296b01347b3173e98438a003b0e88986340b2d8",
#   "logo.png" : "25de09e2d3b01ce1fe00c2ca9a90a2be1aaa05cf",
#   "icon@2x.png" : "5afd9585b08c65fdf105a90c8bd643407cba2787",
#   "pass.json" : "145ea5a5db784fff485126c77ecf7a1fc2a88ee7",
#   "strip@2x.png" : "468fa7bc93e6b55342b56fda09bdce7c829d7d46",
#   "strip.png" : "736d01f84cb73d06e8a9932e43076d68f19461ff"
# }

# ent is a CkZipEntry
set ent [CkZip_GetEntryByName $zip "manifest.json"]
if {[CkZip_get_LastMethodSuccess $zip] == 0} then {
    puts "manifest.json entry not found."
    delete_CkCrypt2 $crypt
    delete_CkZip $zip
    exit
}

# Get the exact content of the manifest.json for later signature verification.
set bdManifest [new_CkBinData]

set success [CkZipEntry_UnzipToBd $ent $bdManifest]

set json [new_CkJsonObject]

CkJsonObject_put_EmitCompact $json 0
CkJsonObject_Load $json [CkZipEntry_unzipToString $ent 0 "utf-8"]
puts [CkJsonObject_emit $json]

delete_CkZipEntry $ent

# For each file in the JSON, get the filename and hex hash value.
CkCrypt2_put_EncodingMode $crypt "hexlower"
CkCrypt2_put_HashAlgorithm $crypt "sha1"

set someHashesFailed 0

set sbHashHex [new_CkStringBuilder]

set bdFileData [new_CkBinData]

set numMembers [CkJsonObject_get_Size $json]
set i 0
while {$i < $numMembers} {
    set filename [CkJsonObject_nameAt $json $i]
    CkStringBuilder_Clear $sbHashHex
    CkStringBuilder_Append $sbHashHex [CkJsonObject_stringAt $json $i]

    set ent [CkZip_GetEntryByName $zip $filename]
    if {[CkZip_get_LastMethodSuccess $zip] == 0} then {
        puts "$filename not found in the pkpass file."
        delete_CkCrypt2 $crypt
        delete_CkZip $zip
        delete_CkBinData $bdManifest
        delete_CkJsonObject $json
        delete_CkStringBuilder $sbHashHex
        delete_CkBinData $bdFileData
        exit
    }

    # Get the data for this file.
    CkBinData_Clear $bdFileData
    set success [CkZipEntry_UnzipToBd $ent $bdFileData]

    set computedHashHex [CkCrypt2_hashBdENC $crypt $bdFileData]
    if {[CkStringBuilder_ContentsEqual $sbHashHex $computedHashHex 0] == 0} then {
        puts "Computed hash does not match stored hash for $filename"
        puts "  computed: $computedHashHex"
        puts "  stored:   [CkStringBuilder_getAsString $sbHashHex]"
        set someHashesFailed 1
    }     else {
        puts "hash verified for $filename($computedHashHex)"
    }

    delete_CkZipEntry $ent

    set i [expr $i + 1]
}

if {$someHashesFailed == 1} then {
    puts "Some hashes failed."
    delete_CkCrypt2 $crypt
    delete_CkZip $zip
    delete_CkBinData $bdManifest
    delete_CkJsonObject $json
    delete_CkStringBuilder $sbHashHex
    delete_CkBinData $bdFileData
    exit
}

# Let's verify the signature..
# First get the signature.
set ent [CkZip_GetEntryByName $zip "signature"]
if {[CkZip_get_LastMethodSuccess $zip] == 0} then {
    puts "signature not found in the pkpass file."
    delete_CkCrypt2 $crypt
    delete_CkZip $zip
    delete_CkBinData $bdManifest
    delete_CkJsonObject $json
    delete_CkStringBuilder $sbHashHex
    delete_CkBinData $bdFileData
    exit
}

set bdSignature [new_CkBinData]

set success [CkZipEntry_UnzipToBd $ent $bdSignature]
delete_CkZipEntry $ent

# Show the contents of the signature in base64 encoding.
puts "Signature:"
puts [CkBinData_getEncoded $bdSignature base64_mime]
puts "----"

# Verify the signature against the manifest.json
CkCrypt2_put_EncodingMode $crypt "base64"
set verified [CkCrypt2_VerifyBdENC $crypt $bdManifest [CkBinData_getEncoded $bdSignature "base64"]]
if {$verified == 0} then {
    puts [CkCrypt2_lastErrorText $crypt]
}

puts "signature verified = $verified"

delete_CkCrypt2 $crypt
delete_CkZip $zip
delete_CkBinData $bdManifest
delete_CkJsonObject $json
delete_CkStringBuilder $sbHashHex
delete_CkBinData $bdFileData
delete_CkBinData $bdSignature