bin/git-http-backend-verify

   1 #!/bin/sh
   2 #
   3 # Abort any push early if the pushing user doesn't have any push permissions
   4 # at all.  This avoids unnecessary traffic and unpacked object pollution.
   5 #
   6 # Set GIT_HTTP_BACKEND_BIN to change the default http-backend binary from
   7 # the default of Config.pm $git_http_backend_bin (which itself has a default
   8 # of "/usr/lib/git-core/git-http-backend")
   9 #
  10 # Note that GIT_PROJECT_ROOT is automatically set to $cfg_reporoot and exported
  11 # any incoming value for it will be ignored.
  12 #
  13 # Also prevents standard error output from git-http-backend cluttering up the
  14 # server's log unless GIT_HTTP_BACKEND_SHOW_ERRORS is set to a non-empty value.
  15
  16 set -e
  17
  18 . @basedir@/shlib.sh
  19
  20 unset GIT_USER_AGENT
  21 if [ -n "$defined_cfg_git_server_ua" ]; then
  22         GIT_USER_AGENT="$cfg_git_server_ua"
  23         export GIT_USER_AGENT
  24 fi
  25
  26 [ -z "$GIT_HTTP_BACKEND_BIN" ] || cfg_git_http_backend_bin="$GIT_HTTP_BACKEND_BIN"
  27 [ -n "$cfg_git_http_backend_bin" ] ||
  28         cfg_git_http_backend_bin="$($cfg_git_bin --exec-path)/git-http-backend"
  29
  30 GIT_PROJECT_ROOT="$cfg_reporoot"
  31 export GIT_PROJECT_ROOT
  32
  33 # This script is called for both fetch and push.
  34 # Only the following conditions trigger a push permissions check:
  35 #
  36 #   1. REQUEST_METHOD=GET
  37 #      and PATH_INFO ends with "/info/refs"
  38 #      and QUERY_STRING has "service=git-receive-pack"
  39 #
  40 #   2. REQUEST_METHOD=POST
  41 #      and PATH_INFO ends with "/git-receive-pack"
  42 #
  43 # Note that there is no check for PATH_INFO being under a certain root as
  44 # GIT_PROJECT_ROOT will be exported and set so all PATH_INFO values are
  45 # effectively forced under the desired root.
  46 #
  47 # The REQUEST_METHOD is validated.  For smart HTTP requests only the project
  48 # name is extracted and validated and the corresponding project directory must
  49 # exist under $cfg_reporoot.  Non-smart HTTP fetch requests (GET or HEAD) are
  50 # passed on unchanged and unchecked.
  51
  52 errorhdrs()
  53 {
  54         printf '%s\r\n' "Status: $1 $2"
  55         printf '%s\r\n' "Expires: Fri, 01 Jan 1980 00:00:00 GMT"
  56         printf '%s\r\n' "Pragma: no-cache"
  57         printf '%s\r\n' "Cache-Control: no-cache, max-age=0, must-revalidate"
  58         [ -z "$3" ] || printf '%s\r\n' "$3"
  59         printf '%s\r\n' "Content-Type: text/plain"
  60         printf '\r\n'
  61 }
  62
  63 msglines()
  64 {
  65         while [ $# -gt 0 ]; do
  66                 printf '%s\n' "$1"
  67                 shift
  68         done
  69 }
  70
  71 internalerr()
  72 {
  73         errorhdrs 500 "Internal Server Error"
  74         if [ $# -eq 0 ]; then
  75                 msglines "Internal Server Error"
  76                 echo "Internal Server Error" >&2
  77         else
  78                 msglines "$@"
  79                 while [ $# -gt 0 ]; do
  80                         printf '%s\n' "$1" >&2
  81                         shift
  82                 done
  83         fi
  84         exit 0
  85 }
  86
  87 methodnotallowed()
  88 {
  89         errorhdrs 405 "Method Not Allowed" "Allow: GET, HEAD, POST"
  90         if [ $# -eq 0 ]; then
  91                 msglines "Method Not Allowed"
  92         else
  93                 msglines "$@"
  94         fi
  95         exit 0
  96 }
  97
  98 forbidden()
  99 {
 100         errorhdrs 403 Forbidden
 101         if [ $# -eq 0 ]; then
 102                 msglines "Forbidden"
 103         else
 104                 msglines "$@"
 105         fi
 106         exit 0
 107 }
 108
 109 needsauth()
 110 {
 111         errorhdrs 401 "Authorization Required"
 112         if [ $# -eq 0 ]; then
 113                 msglines "Authorization Required"
 114         else
 115                 msglines "$@"
 116         fi
 117         exit 0
 118 }
 119
 120 [ -n "$GIT_PROJECT_ROOT" ] || { internalerr 'GIT_PROJECT_ROOT must be set'; exit 1; }
 121
 122 proj=
 123 smart=
 124 suffix=
 125 needsauthcheck=
 126 pathcheck="${PATH_INFO#/}"
 127 if [ "$REQUEST_METHOD" = "GET" -o "$REQUEST_METHOD" = "HEAD" ]; then
 128         # We do not currently validate non-smart GET/HEAD requests.
 129         # There are only 8 possible suffix values that need to be allowed for
 130         # non-smart HTTP GET/HEAD fetches (see http-backend.c):
 131         #   /HEAD
 132         #   /info/refs
 133         #   /objects/info/alternates
 134         #   /objects/info/http-alternates
 135         #   /objects/info/packs
 136         #   /objects/[0-9a-f]{2}/[0-9a-f]{38}
 137         #   /objects/pack/pack-[0-9a-f]{40}.idx
 138         #   /objects/pack/pack-[0-9a-f]{40}.pack
 139         case "$pathcheck" in *"/info/refs")
 140                 proj="${pathcheck%/info/refs}"
 141                 case "&$QUERY_STRING&" in
 142                 *"&service=git-receive-pack&"*)
 143                         smart=1
 144                         needsauthcheck=1
 145                         suffix=info/refs
 146                         ;;
 147                 *"&service=git-upload-pack&"*)
 148                         smart=1
 149                         suffix=info/refs
 150                         ;;
 151                 esac
 152         esac
 153 elif [ "$REQUEST_METHOD" = "POST" ]; then
 154         case "$pathcheck" in
 155         *"/git-receive-pack")
 156                 smart=1
 157                 needsauthcheck=1
 158                 proj="${pathcheck%/git-receive-pack}"
 159                 suffix=git-receive-pack
 160                 ;;
 161         *"/git-upload-pack")
 162                 smart=1
 163                 proj="${pathcheck%/git-upload-pack}"
 164                 suffix=git-upload-pack
 165                 ;;
 166         *)
 167                 forbidden
 168                 exit 1
 169                 ;;
 170         esac
 171 else
 172         methodnotallowed
 173         exit 1
 174 fi
 175
 176 # Reject any project names that start with _
 177 case "$pathcheck" in _*)
 178         forbidden
 179 esac
 180
 181 if [ -n "$smart" ]; then
 182         # add a missing trailing .git
 183         case "$proj" in
 184                 *.git) :;;
 185                 *)
 186                         proj="$proj.git"
 187         esac
 188
 189         reporoot="$cfg_reporoot"
 190         dir="$reporoot/$proj"
 191
 192         # Valid project names never end in .git (we add that automagically), so a valid
 193         # fork can never have .git at the end of any path component except the last.
 194         # We check this to avoid a situation where a certain collection of pushed refs
 195         # could be mistaken for a GIT_DIR.  Git would ultimately complain, but some
 196         # undesirable things could happen along the way.
 197
 198         # Remove the leading $reporoot and trailing .git to get a test string
 199         testpath="${dir#$reporoot/}"
 200         testpath="${testpath%.git}"
 201         case "$testpath/" in *.[Gg][Ii][Tt]/*|_*)
 202                 forbidden
 203                 exit 1
 204         esac
 205
 206         if ! [ -d "$dir" ] || ! [ -f "$dir/HEAD" ] || ! [ -d "$dir/objects" ]; then
 207                 forbidden
 208                 exit 1
 209         fi
 210 fi
 211
 212 if [ -z "$needsauthcheck" ] || [ -z "$smart" ]; then
 213         if [ -n "$GIT_HTTP_BACKEND_SHOW_ERRORS" ]; then
 214                 exec "$cfg_git_http_backend_bin" "$@"
 215         else
 216                 exec "$cfg_git_http_backend_bin" "$@" 2>/dev/null
 217         fi
 218         internalerr "exec failed: $cfg_git_http_backend_bin"
 219         exit 1
 220 fi
 221
 222 projbare="${proj%.git}"
 223
 224 if ! [ -f "$dir/.nofetch" ]; then
 225         forbidden "The $proj project is a mirror and may not be pushed to, sorry"
 226         exit 1
 227 fi
 228
 229 authuser="${REMOTE_USER#/UID=}"
 230 authuuid="${authuser}"
 231 authuser="${authuser%/dnQualifier=*}"
 232 authuuid="${authuuid#$authuser}"
 233 authuuid="${authuuid#/dnQualifier=}"
 234 if [ -z "$authuser" ]; then
 235         needsauth "Only authenticated users may push, sorry"
 236         exit 1
 237 fi
 238 if [ "$authuser" != "mob" -o "$cfg_mob" != "mob" ]; then
 239         if ! useruuid="$("$cfg_basedir/bin/get_user_uuid" "$authuser")" || [ "$useruuid" != "$authuuid" ]; then
 240                 forbidden "The user '$authuser' certificate being used is no longer valid." \
 241                         "You may download a new user certificate at $cfg_webadmurl/edituser.cgi"
 242                 exit 1
 243         fi
 244 fi
 245
 246 if ! "$cfg_basedir/bin/can_user_push_http" "$projbare" "$authuser"; then
 247         # If mob is enabled and mob has push permissions and
 248         # the current user is not the mob then it's a personal mob push
 249         # presuming the special mob directory has been set up
 250         if [ "$cfg_mob" = "mob" -a "$authuser" != "mob" -a -d "$cfg_reporoot/$proj/mob" ] &&
 251                 "$cfg_basedir/bin/can_user_push_http" "$projbare" "mob"; then
 252                 (
 253                         umask 113
 254                         > "$cfg_chroot/etc/sshactive/${authuser},"
 255                         mv -f "$cfg_chroot/etc/sshactive/${authuser}," "$cfg_chroot/etc/sshactive/${authuser}"
 256                 )
 257                 export PATH_INFO="/$proj/mob/$suffix"
 258                 if [ -n "$GIT_HTTP_BACKEND_SHOW_ERRORS" ]; then
 259                         exec "$cfg_git_http_backend_bin" "$@"
 260                 else
 261                         exec "$cfg_git_http_backend_bin" "$@" 2>/dev/null
 262                 fi
 263                 internalerr "exec failed: $cfg_git_http_backend_bin"
 264                 exit 1
 265         fi
 266         forbidden "The user '$authuser' does not have push permissions for project '$proj'." \
 267                 "You may adjust push permissions at $cfg_webadmurl/editproj.cgi?name=$proj"
 268         exit 1
 269 fi
 270
 271 (
 272         umask 113
 273         > "$cfg_chroot/etc/sshactive/${authuser},"
 274         mv -f "$cfg_chroot/etc/sshactive/${authuser}," "$cfg_chroot/etc/sshactive/${authuser}"
 275 )
 276 if [ -n "$GIT_HTTP_BACKEND_SHOW_ERRORS" ]; then
 277         exec "$cfg_git_http_backend_bin" "$@"
 278 else
 279         exec "$cfg_git_http_backend_bin" "$@" 2>/dev/null
 280 fi
 281 internalerr "exec failed: $cfg_git_http_backend_bin"
 282 exit 1