hadolint-1.16.2: src/Hadolint/Rules.hs
{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE OverloadedStrings #-}
module Hadolint.Rules where
import Control.Arrow ((&&&))
import Data.List (dropWhile, foldl', isInfixOf, isPrefixOf, mapAccumL, nub)
import Data.List.NonEmpty (toList)
import qualified Hadolint.Shell as Shell
import Language.Docker.Syntax
import qualified Data.Map as Map
import Data.Semigroup (Semigroup, (<>))
import qualified Data.Set as Set
import qualified Data.Text as Text
import Data.Void (Void)
import qualified ShellCheck.Interface
import ShellCheck.Interface (Severity(..))
import qualified Text.Megaparsec as Megaparsec
import qualified Text.Megaparsec.Char as Megaparsec
data Metadata = Metadata
{ code :: Text.Text
, severity :: Severity
, message :: Text.Text
} deriving (Eq)
-- a check is the application of a rule on a specific part of code
-- the enforced result and the affected position
-- position only records the linenumber at the moment to keep it easy
-- and simple to develop new rules
-- line numbers in the negative range are meant for the global context
data RuleCheck = RuleCheck
{ metadata :: Metadata
, filename :: Filename
, linenumber :: Linenumber
, success :: Bool
} deriving (Eq)
-- | Contains the required parameters for optional rules
newtype RulesConfig = RulesConfig
{ allowedRegistries :: Set.Set Registry -- ^ The docker registries that are allowed in FROM
} deriving (Show, Eq)
instance Ord RuleCheck where
a `compare` b = linenumber a `compare` linenumber b
instance Semigroup RulesConfig where
RulesConfig a <> RulesConfig b = RulesConfig (a <> b)
instance Monoid RulesConfig where
mempty = RulesConfig mempty
mappend = (<>)
type IgnoreRuleParser = Megaparsec.Parsec Void Text.Text
type ParsedFile = [InstructionPos Shell.ParsedShell]
-- | A function to check individual dockerfile instructions.
-- It gets the current state and a line number.
-- It should return the new state and whether or not the check passes for the given instruction.
type SimpleCheckerWithState state
= state -> Linenumber -> Instruction Shell.ParsedShell -> (state, Bool)
-- | A function to check individual dockerfile instructions.
-- It gets the current line number.
-- It should return True if the check passes for the given instruction.
type SimpleCheckerWithLine = (Linenumber -> Instruction Shell.ParsedShell -> Bool)
-- | A function to check individual dockerfile instructions.
-- It should return the new state and a list of Metadata records.
-- Each Metadata record signifies a failing check for the given instruction.
type CheckerWithState state
= state -> Linenumber -> Instruction Shell.ParsedShell -> (state, [Metadata])
link :: Metadata -> Text.Text
link (Metadata code _ _)
| "SC" `Text.isPrefixOf` code = "https://github.com/koalaman/shellcheck/wiki/" <> code
| "DL" `Text.isPrefixOf` code = "https://github.com/hadolint/hadolint/wiki/" <> code
| otherwise = "https://github.com/hadolint/hadolint"
-- a Rule takes a Dockerfile with parsed shell and returns the executed checks
type Rule = ParsedFile -> [RuleCheck]
-- Apply a function on each instruction and create a check
-- for the according line number
mapInstructions :: CheckerWithState state -> state -> Rule
mapInstructions f initialState dockerfile =
let (_, results) = mapAccumL applyRule initialState dockerfile
in concat results
where
applyRule state (InstructionPos (OnBuild i) source linenumber) =
applyWithState state source linenumber i -- All rules applying to instructions also apply to ONBUILD,
-- so we unwrap the OnBuild constructor and check directly the inner
-- instruction
applyRule state (InstructionPos i source linenumber) =
applyWithState state source linenumber i -- Otherwise, normal instructions are not unwrapped
applyWithState state source linenumber instruction =
let (newState, res) = f state linenumber instruction
in (newState, [RuleCheck m source linenumber False | m <- res])
instructionRule ::
Text.Text -> Severity -> Text.Text -> (Instruction Shell.ParsedShell -> Bool) -> Rule
instructionRule code severity message check =
instructionRuleLine code severity message (const check)
instructionRuleLine :: Text.Text -> Severity -> Text.Text -> SimpleCheckerWithLine -> Rule
instructionRuleLine code severity message check =
instructionRuleState code severity message checkAndDropState ()
where
checkAndDropState state line instr = (state, check line instr)
instructionRuleState ::
Text.Text -> Severity -> Text.Text -> SimpleCheckerWithState state -> state -> Rule
instructionRuleState code severity message f = mapInstructions constMetadataCheck
where
meta = Metadata code severity message
constMetadataCheck st ln instr =
let (newSt, success) = f st ln instr
in if not success
then (newSt, [meta])
else (newSt, [])
withState :: a -> b -> (a, b)
withState st res = (st, res)
argumentsRule :: (Shell.ParsedShell -> a) -> Arguments Shell.ParsedShell -> a
argumentsRule applyRule args =
case args of
ArgumentsText as -> applyRule as
ArgumentsList as -> applyRule as
-- Enforce rules on a dockerfile and return failed checks
analyze :: [Rule] -> Dockerfile -> [RuleCheck]
analyze list dockerfile =
[ result -- Keep the result
| rule <- list -- for each rule in the list
, result <- rule parsedFile -- after applying the rule to the file
, notIgnored result -- and only keep failures that were not ignored
]
where
notIgnored RuleCheck {metadata = Metadata {code}, linenumber} = not (wasIgnored code linenumber)
wasIgnored c ln = not $ null [line | (line, codes) <- allIgnores, line == ln, c `elem` codes]
allIgnores = ignored dockerfile
parsedFile = map (fmap Shell.parseShell) dockerfile
ignored :: Dockerfile -> [(Linenumber, [Text.Text])]
ignored dockerfile =
[(l + 1, ignores) | (l, Just ignores) <- map (lineNumber &&& extractIgnored) dockerfile]
where
extractIgnored = ignoreFromInstruction . instruction
ignoreFromInstruction (Comment comment) = parseComment comment
ignoreFromInstruction _ = Nothing
-- | Parses the comment text and extracts the ignored rule names
parseComment :: Text.Text -> Maybe [Text.Text]
parseComment = Megaparsec.parseMaybe commentParser
commentParser :: IgnoreRuleParser [Text.Text]
commentParser =
spaces >> -- The parser for the ignored rules
string "hadolint" >>
spaces1 >>
string "ignore=" >>
spaces >>
Megaparsec.sepBy1 ruleName (spaces >> string "," >> spaces)
string = Megaparsec.string
spaces = Megaparsec.takeWhileP Nothing space
spaces1 = Megaparsec.takeWhile1P Nothing space
space c = c == ' ' || c == '\t'
ruleName = Megaparsec.takeWhile1P Nothing (\c -> c `elem` ("DLSC0123456789" :: String))
rules :: [Rule]
rules =
[ absoluteWorkdir
, shellcheck
, invalidCmd
, copyInsteadAdd
, copyEndingSlash
, copyFromExists
, copyFromAnother
, fromAliasUnique
, noRootUser
, noCd
, noSudo
, noAptGetUpgrade
, noApkUpgrade
, noLatestTag
, noUntagged
, aptGetVersionPinned
, aptGetCleanup
, apkAddVersionPinned
, apkAddNoCache
, useAdd
, pipVersionPinned
, npmVersionPinned
, invalidPort
, aptGetNoRecommends
, aptGetYes
, wgetOrCurl
, hasNoMaintainer
, multipleCmds
, multipleEntrypoints
, useShell
, useJsonArgs
, usePipefail
]
optionalRules :: RulesConfig -> [Rule]
optionalRules RulesConfig {allowedRegistries} = [registryIsAllowed allowedRegistries]
allFromImages :: ParsedFile -> [(Linenumber, BaseImage)]
allFromImages dockerfile = [(l, f) | (l, From f) <- instr]
where
instr = fmap (lineNumber &&& instruction) dockerfile
allAliasedImages :: ParsedFile -> [(Linenumber, ImageAlias)]
allAliasedImages dockerfile =
[(l, alias) | (l, Just alias) <- map extractAlias (allFromImages dockerfile)]
where
extractAlias (l, f) = (l, fromAlias f)
allImageNames :: ParsedFile -> [(Linenumber, Text.Text)]
allImageNames dockerfile = [(l, fromName baseImage) | (l, baseImage) <- allFromImages dockerfile]
-- | Returns a list of all image aliases in FROM instructions that
-- are defined before the given line number.
previouslyDefinedAliases :: Linenumber -> ParsedFile -> [Text.Text]
previouslyDefinedAliases line dockerfile =
[i | (l, ImageAlias i) <- allAliasedImages dockerfile, l < line]
-- | Returns the result of running the check function on the image alias
-- name, if the passed instruction is a FROM instruction with a stage alias.
-- Otherwise, returns True.
aliasMustBe :: (Text.Text -> Bool) -> Instruction a -> Bool
aliasMustBe predicate fromInstr =
case fromInstr of
From BaseImage {alias = Just (ImageAlias as)} -> predicate as
_ -> True
fromName :: BaseImage -> Text.Text
fromName BaseImage {image = Image {imageName}} = imageName
fromAlias :: BaseImage -> Maybe ImageAlias
fromAlias BaseImage {alias} = alias
-------------
-- RULES --
-------------
shellcheck :: Rule
shellcheck = mapInstructions check Shell.defaultShellOpts
where
check :: CheckerWithState Shell.ShellOpts
check _ _ (From _) = (Shell.defaultShellOpts, []) -- Reset the state
check st _ (Arg name _) = (Shell.addVars [name] st, [])
check st _ (Env pairs) = (Shell.addVars (map fst pairs) st, [])
check st _ (Shell (ArgumentsList script)) = (Shell.setShell (Shell.original script) st, [])
check st _ (Shell (ArgumentsText script)) = (Shell.setShell (Shell.original script) st, [])
check st _ (Run (ArgumentsList script)) = (st, doCheck st script)
check st _ (Run (ArgumentsText script)) = (st, doCheck st script)
check st _ _ = (st, [])
doCheck opts script = nub [commentMetadata c | c <- Shell.shellcheck opts script]
-- | Converts ShellCheck errors into our own errors type
commentMetadata :: ShellCheck.Interface.PositionedComment -> Metadata
commentMetadata c = Metadata (Text.pack ("SC" ++ show (code c))) (severity c) (Text.pack (message c))
where
severity pc = ShellCheck.Interface.cSeverity $ ShellCheck.Interface.pcComment pc
code pc = ShellCheck.Interface.cCode $ ShellCheck.Interface.pcComment pc
message pc = ShellCheck.Interface.cMessage $ ShellCheck.Interface.pcComment pc
absoluteWorkdir :: Rule
absoluteWorkdir = instructionRule code severity message check
where
code = "DL3000"
severity = ErrorC
message = "Use absolute WORKDIR"
check (Workdir loc)
| "$" `Text.isPrefixOf` loc = True
| "/" `Text.isPrefixOf` loc = True
| otherwise = False
check _ = True
hasNoMaintainer :: Rule
hasNoMaintainer = instructionRule code severity message check
where
code = "DL4000"
severity = ErrorC
message = "MAINTAINER is deprecated"
check (Maintainer _) = False
check _ = True
-- Check if a command contains a program call in the Run instruction
usingProgram :: String -> Shell.ParsedShell -> Bool
usingProgram prog args = not $ null [cmd | cmd <- Shell.findCommandNames args, cmd == prog]
multipleCmds :: Rule
multipleCmds = instructionRuleState code severity message check False
where
code = "DL4003"
severity = WarningC
message =
"Multiple `CMD` instructions found. If you list more than one `CMD` then only the last \
\`CMD` will take effect"
check _ _ From {} = withState False True -- Reset the state each time we find a FROM
check st _ Cmd {} = withState True (not st) -- Remember we found a CMD, fail if we found a CMD before
check st _ _ = withState st True
multipleEntrypoints :: Rule
multipleEntrypoints = instructionRuleState code severity message check False
where
code = "DL4004"
severity = ErrorC
message =
"Multiple `ENTRYPOINT` instructions found. If you list more than one `ENTRYPOINT` then \
\only the last `ENTRYPOINT` will take effect"
check _ _ From {} = withState False True -- Reset the state each time we find a FROM
check st _ Entrypoint {} = withState True (not st) -- Remember we found an ENTRYPOINT
-- and fail if we found another one before
check st _ _ = withState st True
wgetOrCurl :: Rule
wgetOrCurl = instructionRuleState code severity message check Set.empty
where
code = "DL4001"
severity = WarningC
message = "Either use Wget or Curl but not both"
check state _ (Run args) = argumentsRule (detectDoubleUsage state) args
check state _ _ = withState state True
detectDoubleUsage state args =
let newArgs = extractCommands args
newState = Set.union state newArgs
in withState newState (Set.size newState < 2)
extractCommands args =
Set.fromList [w | w <- Shell.findCommandNames args, w == "curl" || w == "wget"]
invalidCmd :: Rule
invalidCmd = instructionRule code severity message check
where
code = "DL3001"
severity = InfoC
message =
"For some bash commands it makes no sense running them in a Docker container like `ssh`, \
\`vim`, `shutdown`, `service`, `ps`, `free`, `top`, `kill`, `mount`, `ifconfig`"
check (Run args) = argumentsRule detectInvalid args
check _ = True
detectInvalid args = null [arg | arg <- Shell.findCommandNames args, arg `elem` invalidCmds]
invalidCmds = ["ssh", "vim", "shutdown", "service", "ps", "free", "top", "kill", "mount"]
noRootUser :: Rule
noRootUser dockerfile = instructionRuleState code severity message check Nothing dockerfile
where
code = "DL3002"
severity = WarningC
message = "Last USER should not be root"
check _ _ (From from) = withState (Just from) True -- Remember the last FROM instruction found
check st@(Just from) line (User user)
| isRoot user && lastUserIsRoot from line = withState st False
| otherwise = withState st True
check st _ _ = withState st True
--
--
lastUserIsRoot from line = Map.lookup from rootStages == Just line
--
--
rootStages :: Map.Map BaseImage Linenumber
rootStages =
let indexedInstructions = map (instruction &&& lineNumber) dockerfile
(_, usersMap) = foldl' buildMap (Nothing, Map.empty) indexedInstructions
in usersMap
--
--
buildMap (_, st) (From from, _) = (Just from, st) -- Remember the FROM we are currently inspecting
buildMap (Just from, st) (User user, line)
| isRoot user = (Just from, Map.insert from line st) -- Remember the line with a root user
| otherwise = (Just from, Map.delete from st) -- Forget there was a root used for this FROM
buildMap st _ = st
--
--
isRoot user =
Text.isPrefixOf "root:" user || Text.isPrefixOf "0:" user || user == "root" || user == "0"
noCd :: Rule
noCd = instructionRule code severity message check
where
code = "DL3003"
severity = WarningC
message = "Use WORKDIR to switch to a directory"
check (Run args) = argumentsRule (not . usingProgram "cd") args
check _ = True
noSudo :: Rule
noSudo = instructionRule code severity message check
where
code = "DL3004"
severity = ErrorC
message =
"Do not use sudo as it leads to unpredictable behavior. Use a tool like gosu to enforce \
\root"
check (Run args) = argumentsRule (not . usingProgram "sudo") args
check _ = True
noAptGetUpgrade :: Rule
noAptGetUpgrade = instructionRule code severity message check
where
code = "DL3005"
severity = ErrorC
message = "Do not use apt-get upgrade or dist-upgrade"
check (Run args) =
argumentsRule (Shell.noCommands (Shell.cmdHasArgs "apt-get" ["upgrade"])) args
check _ = True
noUntagged :: Rule
noUntagged dockerfile = instructionRuleLine code severity message check dockerfile
where
code = "DL3006"
severity = WarningC
message = "Always tag the version of an image explicitly"
check _ (From BaseImage {image = (Image _ "scratch")}) = True
check _ (From BaseImage {digest = Just _}) = True
check line (From BaseImage {image = (Image _ i), tag = Nothing}) =
i `elem` previouslyDefinedAliases line dockerfile
check _ _ = True
noLatestTag :: Rule
noLatestTag = instructionRule code severity message check
where
code = "DL3007"
severity = WarningC
message =
"Using latest is prone to errors if the image will ever update. Pin the version explicitly \
\to a release tag"
check (From BaseImage {tag = Just t}) = t /= "latest"
check _ = True
aptGetVersionPinned :: Rule
aptGetVersionPinned = instructionRule code severity message check
where
code = "DL3008"
severity = WarningC
message =
"Pin versions in apt get install. Instead of `apt-get install <package>` use `apt-get \
\install <package>=<version>`"
check (Run args) = argumentsRule (all versionFixed . aptGetPackages) args
check _ = True
versionFixed package = "=" `isInfixOf` package
aptGetPackages :: Shell.ParsedShell -> [String]
aptGetPackages args =
[ arg
| cmd <- dropTarget <$> Shell.findCommands args
, Shell.cmdHasArgs "apt-get" ["install"] cmd
, arg <- Shell.getArgsNoFlags cmd
, arg /= "install"
]
where
dropTarget = Shell.dropFlagArg ["t", "target-release"]
aptGetCleanup :: Rule
aptGetCleanup dockerfile = instructionRuleState code severity message check Nothing dockerfile
where
code = "DL3009"
severity = InfoC
message = "Delete the apt-get lists after installing something"
-- | 'check' returns a tuple (state, check_result)
-- The state in this case is the FROM instruction where the current instruction we are
-- inspecting is nested in.
-- We only care for users to delete the lists folder if the FROM clase we're is is the last one
-- or if it is used as the base image for another FROM clause.
check _ line f@(From _) = withState (Just (line, f)) True -- Remember the last FROM instruction found
check st@(Just (line, From baseimage)) _ (Run args) =
withState st (argumentsRule (didNotForgetToCleanup line baseimage) args)
check st _ _ = withState st True
-- Check all commands in the script for the presence of apt-get update
-- If the command is there, then we need to verify that the user is also removing the lists folder
didNotForgetToCleanup line baseimage args
| not (hasUpdate args) || not (imageIsUsed line baseimage) = True
| otherwise = hasCleanup args
hasCleanup args =
any (Shell.cmdHasArgs "rm" ["-rf", "/var/lib/apt/lists/*"]) (Shell.findCommands args)
hasUpdate args = any (Shell.cmdHasArgs "apt-get" ["update"]) (Shell.findCommands args)
imageIsUsed line baseimage = isLastImage line baseimage || imageIsUsedLater line baseimage
isLastImage line baseimage =
case reverse (allFromImages dockerfile) of
lst:_ -> (line, baseimage) == lst
_ -> True
imageIsUsedLater line baseimage =
case fromAlias baseimage of
Nothing -> True
Just (ImageAlias alias) ->
alias `elem` [i | (l, i) <- allImageNames dockerfile, l > line]
noApkUpgrade :: Rule
noApkUpgrade = instructionRule code severity message check
where
code = "DL3017"
severity = ErrorC
message = "Do not use apk upgrade"
check (Run args) = argumentsRule (Shell.noCommands (Shell.cmdHasArgs "apk" ["upgrade"])) args
check _ = True
apkAddVersionPinned :: Rule
apkAddVersionPinned = instructionRule code severity message check
where
code = "DL3018"
severity = WarningC
message =
"Pin versions in apk add. Instead of `apk add <package>` use `apk add <package>=<version>`"
check (Run args) = argumentsRule (\as -> and [versionFixed p | p <- apkAddPackages as]) args
check _ = True
versionFixed package = "=" `isInfixOf` package
apkAddPackages :: Shell.ParsedShell -> [String]
apkAddPackages args =
[ arg
| cmd <- dropTarget <$> Shell.findCommands args
, Shell.cmdHasArgs "apk" ["add"] cmd
, arg <- Shell.getArgsNoFlags cmd
, arg /= "add"
]
where
dropTarget = Shell.dropFlagArg ["t", "virtual", "repository"]
apkAddNoCache :: Rule
apkAddNoCache = instructionRule code severity message check
where
code = "DL3019"
severity = InfoC
message =
"Use the `--no-cache` switch to avoid the need to use `--update` and remove \
\`/var/cache/apk/*` when done installing packages"
check (Run args) = argumentsRule (Shell.noCommands forgotCacheOption) args
check _ = True
forgotCacheOption cmd = Shell.cmdHasArgs "apk" ["add"] cmd && not (Shell.hasFlag "no-cache" cmd)
useAdd :: Rule
useAdd = instructionRule code severity message check
where
code = "DL3010"
severity = InfoC
message = "Use ADD for extracting archives into an image"
check (Copy (CopyArgs srcs _ _ _)) =
and
[ not (format `Text.isSuffixOf` src)
| SourcePath src <- toList srcs
, format <- archiveFormats
]
check _ = True
archiveFormats = [".tar", ".gz", ".bz2", "xz"]
invalidPort :: Rule
invalidPort = instructionRule code severity message check
where
code = "DL3011"
severity = ErrorC
message = "Valid UNIX ports range from 0 to 65535"
check (Expose (Ports ports)) =
and [p <= 65535 | Port p _ <- ports] &&
and [l <= 65535 && m <= 65535 | PortRange l m _ <- ports]
check _ = True
pipVersionPinned :: Rule
pipVersionPinned = instructionRule code severity message check
where
code = "DL3013"
severity = WarningC
message =
"Pin versions in pip. Instead of `pip install <package>` use `pip install \
\<package>==<version>`"
check (Run args) = argumentsRule (Shell.noCommands forgotToPinVersion) args
check _ = True
forgotToPinVersion cmd =
isPipInstall cmd && not (hasBuildConstraint cmd) && not (all versionFixed (packages cmd))
-- Check if the command is a pip* install command, and that specific pacakges are being listed
isPipInstall cmd =
case Shell.getCommandName cmd of
Just ('p':'i':'p':_) -> relevantInstall cmd
_ -> False
-- If the user is installing requirements from a file or just the local module, then we are not interested
-- in running this rule
relevantInstall cmd =
["install"] `isInfixOf` Shell.getAllArgs cmd &&
not (["-r"] `isInfixOf` Shell.getAllArgs cmd || ["."] `isInfixOf` Shell.getAllArgs cmd)
hasBuildConstraint = Shell.hasFlag "constraint"
packages cmd = stripInstallPrefix $ Shell.getArgsNoFlags $ Shell.dropFlagArg ["i", "index-url", "extra-index-url"] cmd
versionFixed package = hasVersionSymbol package || isVersionedGit package
isVersionedGit package = "git+http" `isInfixOf` package && "@" `isInfixOf` package
versionSymbols = ["==", ">=", "<=", ">", "<", "!=", "~=", "==="]
hasVersionSymbol package = or [s `isInfixOf` package | s <- versionSymbols]
stripInstallPrefix :: [String] -> [String]
stripInstallPrefix = dropWhile (== "install")
{-|
Rule for pinning NPM packages to version, tag, or commit
supported formats by Hadolint
npm install (with no args, in package dir)
npm install [<@scope>/]<name>
npm install [<@scope>/]<name>@<tag>
npm install [<@scope>/]<name>@<version>
npm install git[+http|+https]://<git-host>/<git-user>/<repo-name>[#<commit>|#semver:<semver>]
npm install git+ssh://<git-host>:<git-user>/<repo-name>[#<commit>|#semver:<semver>]
-}
npmVersionPinned :: Rule
npmVersionPinned = instructionRule code severity message check
where
code = "DL3016"
severity = WarningC
message =
"Pin versions in npm. Instead of `npm install <package>` use `npm install \
\<package>@<version>`"
check (Run args) = argumentsRule (Shell.noCommands forgotToPinVersion) args
check _ = True
forgotToPinVersion cmd =
isNpmInstall cmd && installIsFirst cmd && not (all versionFixed (packages cmd))
isNpmInstall = Shell.cmdHasArgs "npm" ["install"]
installIsFirst cmd = ["install"] `isPrefixOf` Shell.getArgsNoFlags cmd
packages cmd = stripInstallPrefix (Shell.getArgsNoFlags cmd)
versionFixed package =
if hasGitPrefix package
then isVersionedGit package
else hasVersionSymbol package
gitPrefixes = ["git://", "git+ssh://", "git+http://", "git+https://"]
hasGitPrefix package = or [p `isPrefixOf` package | p <- gitPrefixes]
isVersionedGit package = "#" `isInfixOf` package
hasVersionSymbol package = "@" `isInfixOf` dropScope package
where
dropScope pkg =
if "@" `isPrefixOf` pkg
then dropWhile ('/' <) pkg
else pkg
aptGetYes :: Rule
aptGetYes = instructionRule code severity message check
where
code = "DL3014"
severity = WarningC
message = "Use the `-y` switch to avoid manual input `apt-get -y install <package>`"
check (Run args) = argumentsRule (Shell.noCommands forgotAptYesOption) args
check _ = True
forgotAptYesOption cmd = isAptGetInstall cmd && not (hasYesOption cmd)
isAptGetInstall = Shell.cmdHasArgs "apt-get" ["install"]
hasYesOption cmd =
"y" `elem` allFlags cmd ||
"yes" `elem` allFlags cmd ||
length (filter (== "q") (allFlags cmd)) > 1 || "assume-yes" `elem` allFlags cmd
allFlags cmd = snd <$> Shell.getAllFlags cmd
aptGetNoRecommends :: Rule
aptGetNoRecommends = instructionRule code severity message check
where
code = "DL3015"
severity = InfoC
message = "Avoid additional packages by specifying `--no-install-recommends`"
check (Run args) = argumentsRule (Shell.noCommands forgotNoInstallRecommends) args
check _ = True
forgotNoInstallRecommends cmd = isAptGetInstall cmd && not (disablesRecommendOption cmd)
isAptGetInstall = Shell.cmdHasArgs "apt-get" ["install"]
disablesRecommendOption cmd =
Shell.hasFlag "no-install-recommends" cmd ||
"APT::Install-Recommends=false" `elem` Shell.getAllArgs cmd
isArchive :: Text.Text -> Bool
isArchive path =
True `elem`
[ ftype `Text.isSuffixOf` path
| ftype <-
[ ".tar"
, ".gz"
, ".bz2"
, ".xz"
, ".zip"
, ".tgz"
, ".tb2"
, ".tbz"
, ".tbz2"
, ".lz"
, ".lzma"
, ".tlz"
, ".txz"
, ".Z"
, ".tZ"
]
]
isUrl :: Text.Text -> Bool
isUrl path = True `elem` [proto `Text.isPrefixOf` path | proto <- ["https://", "http://"]]
copyInsteadAdd :: Rule
copyInsteadAdd = instructionRule code severity message check
where
code = "DL3020"
severity = ErrorC
message = "Use COPY instead of ADD for files and folders"
check (Add (AddArgs srcs _ _)) =
and [isArchive src || isUrl src | SourcePath src <- toList srcs]
check _ = True
copyEndingSlash :: Rule
copyEndingSlash = instructionRule code severity message check
where
code = "DL3021"
severity = ErrorC
message = "COPY with more than 2 arguments requires the last argument to end with /"
check (Copy (CopyArgs sources t _ _))
| length sources > 1 = endsWithSlash t
| otherwise = True
check _ = True
endsWithSlash (TargetPath t) = Text.last t == '/' -- it is safe to use last, as the target is never empty
copyFromExists :: Rule
copyFromExists dockerfile = instructionRuleLine code severity message check dockerfile
where
code = "DL3022"
severity = WarningC
message = "COPY --from should reference a previously defined FROM alias"
check l (Copy (CopyArgs _ _ _ (CopySource s))) = s `elem` previouslyDefinedAliases l dockerfile
check _ _ = True
copyFromAnother :: Rule
copyFromAnother = instructionRuleState code severity message check Nothing
where
code = "DL3023"
severity = ErrorC
message = "COPY --from should reference a previously defined FROM alias"
-- | 'check' returns a tuple (state, check_result)
-- The state in this case is the FROM instruction where the current instruction we are
-- inspecting is nested in.
check _ _ f@(From _) = withState (Just f) True -- Remember the last FROM instruction found
check st@(Just fromInstr) _ (Copy (CopyArgs _ _ _ (CopySource stageName))) =
withState st (aliasMustBe (/= stageName) fromInstr) -- Cannot copy from itself!
check state _ _ = withState state True
fromAliasUnique :: Rule
fromAliasUnique dockerfile = instructionRuleLine code severity message check dockerfile
where
code = "DL3024"
severity = ErrorC
message = "FROM aliases (stage names) must be unique"
check line = aliasMustBe (not . alreadyTaken line)
alreadyTaken line alias = alias `elem` previouslyDefinedAliases line dockerfile
useShell :: Rule
useShell = instructionRule code severity message check
where
code = "DL4005"
severity = WarningC
message = "Use SHELL to change the default shell"
check (Run args) = argumentsRule (Shell.noCommands (Shell.cmdHasArgs "ln" ["/bin/sh"])) args
check _ = True
useJsonArgs :: Rule
useJsonArgs = instructionRule code severity message check
where
code = "DL3025"
severity = WarningC
message = "Use arguments JSON notation for CMD and ENTRYPOINT arguments"
check (Cmd (ArgumentsText _)) = False
check (Entrypoint (ArgumentsText _)) = False
check _ = True
usePipefail :: Rule
usePipefail = instructionRuleState code severity message check False
where
code = "DL4006"
severity = WarningC
message = "Set the SHELL option -o pipefail before RUN with a pipe in it"
check _ _ From {} = (False, True) -- Reset the state each time we find a new FROM
check _ _ (Shell args)
| argumentsRule isPowerShell args = (True, True)
| otherwise = (argumentsRule hasPipefailOption args, True)
check False _ (Run args) = (False, argumentsRule notHasPipes args)
check st _ _ = (st, True)
isPowerShell (Shell.ParsedShell orig _) = "pwsh" `Text.isPrefixOf` orig
notHasPipes script = not (Shell.hasPipes script)
hasPipefailOption script =
not $
null
[ True
| cmd <- Shell.findCommands script
, validShell <- ["/bin/bash", "/bin/zsh", "/bin/ash", "bash", "zsh", "ash"]
, Shell.getCommandName cmd == Just validShell
, Shell.hasFlag "o" cmd
, arg <- Shell.getAllArgs cmd
, arg == "pipefail"
]
registryIsAllowed :: Set.Set Registry -> Rule
registryIsAllowed allowed = instructionRuleState code severity message check Set.empty
where
code = "DL3026"
severity = ErrorC
message = "Use only an allowed registry in the FROM image"
check st _ (From BaseImage {image, alias}) = withState (Set.insert alias st) (doCheck st image)
check st _ _ = (st, True)
-- |Transforms an Image into a Maybe ImageAlias by using the Image name
toImageAlias = Just . ImageAlias . imageName
-- | Returns True if the image being used is a previous aliased image
-- or if the image registry is in the set of allowed registries
doCheck st img = Set.member (toImageAlias img) st || Set.null allowed || isAllowed img
isAllowed Image {registryName = Just registry} = Set.member registry allowed
isAllowed Image {registryName = Nothing, imageName} =
imageName == "scratch" ||
Set.member "docker.io" allowed || Set.member "hub.docker.com" allowed