Jitsi Meet: .../luajwtjitsi.lib.lua

"Fossies" - the Fresh Open Source Software Archive

Member "jitsi-meet-7315/resources/prosody-plugins/luajwtjitsi.lib.lua" (2 Jun 2023, 8278 Bytes) of package /linux/misc/jitsi-meet-7315.tar.gz:

As a special service "Fossies" has tried to format the requested source page into HTML format using (guessed) Lua source code syntax highlighting (style: standard) with prefixed line numbers and code folding option. Alternatively you can here view or download the uninterpreted source code file.

1 local cjson_safe = require 'cjson.safe' 2 local basexx = require 'basexx' 3 local digest = require 'openssl.digest' 4 local hmac = require 'openssl.hmac' 5 local pkey = require 'openssl.pkey' 6 7 -- Generates an RSA signature of the data. 8 -- @param data The data to be signed. 9 -- @param key The private signing key in PEM format. 10 -- @param algo The digest algorithm to user when generating the signature: sha256, sha384, or sha512. 11 -- @return The signature or nil and an error message. 12 local function signRS (data, key, algo) 13 local privkey = pkey.new(key) 14 if privkey == nil then 15 return nil, 'Not a private PEM key' 16 else 17 local datadigest = digest.new(algo):update(data) 18 return privkey:sign(datadigest) 19 end 20 end 21 22 -- Verifies an RSA signature on the data. 23 -- @param data The signed data. 24 -- @param signature The signature to be verified. 25 -- @param key The public key of the signer. 26 -- @param algo The digest algorithm to user when generating the signature: sha256, sha384, or sha512. 27 -- @return True if the signature is valid, false otherwise. Also returns false if the key is invalid. 28 local function verifyRS (data, signature, key, algo) 29 local pubkey = pkey.new(key) 30 if pubkey == nil then 31 return false 32 end 33 34 local datadigest = digest.new(algo):update(data) 35 return pubkey:verify(signature, datadigest) 36 end 37 38 local alg_sign = { 39 ['HS256'] = function(data, key) return hmac.new(key, 'sha256'):final(data) end, 40 ['HS384'] = function(data, key) return hmac.new(key, 'sha384'):final(data) end, 41 ['HS512'] = function(data, key) return hmac.new(key, 'sha512'):final(data) end, 42 ['RS256'] = function(data, key) return signRS(data, key, 'sha256') end, 43 ['RS384'] = function(data, key) return signRS(data, key, 'sha384') end, 44 ['RS512'] = function(data, key) return signRS(data, key, 'sha512') end 45 } 46 47 local alg_verify = { 48 ['HS256'] = function(data, signature, key) return signature == alg_sign['HS256'](data, key) end, 49 ['HS384'] = function(data, signature, key) return signature == alg_sign['HS384'](data, key) end, 50 ['HS512'] = function(data, signature, key) return signature == alg_sign['HS512'](data, key) end, 51 ['RS256'] = function(data, signature, key) return verifyRS(data, signature, key, 'sha256') end, 52 ['RS384'] = function(data, signature, key) return verifyRS(data, signature, key, 'sha384') end, 53 ['RS512'] = function(data, signature, key) return verifyRS(data, signature, key, 'sha512') end 54 } 55 56 -- Splits a token into segments, separated by '.'. 57 -- @param token The full token to be split. 58 -- @return A table of segments. 59 local function split_token(token) 60 local segments={} 61 for str in string.gmatch(token, "([^\\.]+)") do 62 table.insert(segments, str) 63 end 64 return segments 65 end 66 67 -- Parses a JWT token into it's header, body, and signature. 68 -- @param token The JWT token to be parsed. 69 -- @return A JSON header and body represented as a table, and a signature. 70 local function parse_token(token) 71 local segments=split_token(token) 72 if #segments ~= 3 then 73 return nil, nil, nil, "Invalid token" 74 end 75 76 local header, err = cjson_safe.decode(basexx.from_url64(segments[1])) 77 if err then 78 return nil, nil, nil, "Invalid header" 79 end 80 81 local body, err = cjson_safe.decode(basexx.from_url64(segments[2])) 82 if err then 83 return nil, nil, nil, "Invalid body" 84 end 85 86 local sig, err = basexx.from_url64(segments[3]) 87 if err then 88 return nil, nil, nil, "Invalid signature" 89 end 90 91 return header, body, sig 92 end 93 94 -- Removes the signature from a JWT token. 95 -- @param token A JWT token. 96 -- @return The token without its signature. 97 local function strip_signature(token) 98 local segments=split_token(token) 99 if #segments ~= 3 then 100 return nil, nil, nil, "Invalid token" 101 end 102 103 table.remove(segments) 104 return table.concat(segments, ".") 105 end 106 107 -- Verifies that a claim is in a list of allowed claims. Allowed claims can be exact values, or the 108 -- catch all wildcard '*'. 109 -- @param claim The claim to be verified. 110 -- @param acceptedClaims A table of accepted claims. 111 -- @return True if the claim was allowed, false otherwise. 112 local function verify_claim(claim, acceptedClaims) 113 for i, accepted in ipairs(acceptedClaims) do 114 if accepted == '*' then 115 return true; 116 end 117 if claim == accepted then 118 return true; 119 end 120 end 121 122 return false; 123 end 124 125 local M = {} 126 127 -- Encodes the data into a signed JWT token. 128 -- @param data The data the put in the body of the JWT token. 129 -- @param key The key to use for signing the JWT token. 130 -- @param alg The signature algorithm to use: HS256, HS384, HS512, RS256, RS384, or RS512. 131 -- @param header Additional values to put in the JWT header. 132 -- @param The resulting JWT token, or nil and an error message. 133 function M.encode(data, key, alg, header) 134 if type(data) ~= 'table' then return nil, "Argument #1 must be table" end 135 if type(key) ~= 'string' then return nil, "Argument #2 must be string" end 136 137 alg = alg or "HS256" 138 139 if not alg_sign[alg] then 140 return nil, "Algorithm not supported" 141 end 142 143 header = header or {} 144 145 header['typ'] = 'JWT' 146 header['alg'] = alg 147 148 local headerEncoded, err = cjson_safe.encode(header) 149 if headerEncoded == nil then 150 return nil, err 151 end 152 153 local dataEncoded, err = cjson_safe.encode(data) 154 if dataEncoded == nil then 155 return nil, err 156 end 157 158 local segments = { 159 basexx.to_url64(headerEncoded), 160 basexx.to_url64(dataEncoded) 161 } 162 163 local signing_input = table.concat(segments, ".") 164 local signature, error = alg_sign[alg](signing_input, key) 165 if signature == nil then 166 return nil, error 167 end 168 169 segments[#segments+1] = basexx.to_url64(signature) 170 171 return table.concat(segments, ".") 172 end 173 174 -- Verify that the token is valid, and if it is return the decoded JSON payload data. 175 -- @param token The token to verify. 176 -- @param expectedAlgo The signature algorithm the caller expects the token to be signed with: 177 -- HS256, HS384, HS512, RS256, RS384, or RS512. 178 -- @param key The verification key used for the signature. 179 -- @param acceptedIssuers Optional table of accepted issuers. If not nil, the 'iss' claim will be 180 -- checked against this list. 181 -- @param acceptedAudiences Optional table of accepted audiences. If not nil, the 'aud' claim will 182 -- be checked against this list. 183 -- @return A table representing the JSON body of the token, or nil and an error message. 184 function M.verify(token, expectedAlgo, key, acceptedIssuers, acceptedAudiences) 185 if type(token) ~= 'string' then return nil, "token argument must be string" end 186 if type(expectedAlgo) ~= 'string' then return nil, "algorithm argument must be string" end 187 if type(key) ~= 'string' then return nil, "key argument must be string" end 188 if acceptedIssuers ~= nil and type(acceptedIssuers) ~= 'table' then 189 return nil, "acceptedIssuers argument must be table" 190 end 191 if acceptedAudiences ~= nil and type(acceptedAudiences) ~= 'table' then 192 return nil, "acceptedAudiences argument must be table" 193 end 194 195 if not alg_verify[expectedAlgo] then 196 return nil, "Algorithm not supported" 197 end 198 199 local header, body, sig, err = parse_token(token) 200 if err ~= nil then 201 return nil, err 202 end 203 204 -- Validate header 205 if not header.typ or header.typ ~= "JWT" then 206 return nil, "Invalid typ" 207 end 208 209 if not header.alg or header.alg ~= expectedAlgo then 210 return nil, "Invalid or incorrect alg" 211 end 212 213 -- Validate signature 214 if not alg_verify[expectedAlgo](strip_signature(token), sig, key) then 215 return nil, 'Invalid signature' 216 end 217 218 -- Validate body 219 if body.exp and type(body.exp) ~= "number" then 220 return nil, "exp must be number" 221 end 222 223 if body.nbf and type(body.nbf) ~= "number" then 224 return nil, "nbf must be number" 225 end 226 227 228 if body.exp and os.time() >= body.exp then 229 return nil, "Not acceptable by exp" 230 end 231 232 if body.nbf and os.time() < body.nbf then 233 return nil, "Not acceptable by nbf" 234 end 235 236 if acceptedIssuers ~= nil then 237 local issClaim = body.iss; 238 if issClaim == nil then 239 return nil, "'iss' claim is missing"; 240 end 241 if not verify_claim(issClaim, acceptedIssuers) then 242 return nil, "invalid 'iss' claim"; 243 end 244 end 245 246 if acceptedAudiences ~= nil then 247 local audClaim = body.aud; 248 if audClaim == nil then 249 return nil, "'aud' claim is missing"; 250 end 251 if not verify_claim(audClaim, acceptedAudiences) then 252 return nil, "invalid 'aud' claim"; 253 end 254 end 255 256 return body 257 end 258 259 return M