Patch #1484695: The tarfile module now raises a HeaderError exception
if a buffer given to frombuf() is invalid.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 1b8f140..00789f3 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -280,6 +280,9 @@
class StreamError(TarError):
"""Exception for unsupported operations on stream-like TarFiles."""
pass
+class HeaderError(TarError):
+ """Exception for invalid headers."""
+ pass
#---------------------------
# internal stream interface
@@ -819,9 +822,17 @@
"""Construct a TarInfo object from a 512 byte string buffer.
"""
if len(buf) != BLOCKSIZE:
- raise ValueError("truncated header")
+ raise HeaderError("truncated header")
if buf.count(NUL) == BLOCKSIZE:
- raise ValueError("empty header")
+ raise HeaderError("empty header")
+
+ try:
+ chksum = nti(buf[148:156])
+ except ValueError:
+ raise HeaderError("invalid header")
+
+ if chksum not in calc_chksums(buf):
+ raise HeaderError("bad checksum")
tarinfo = cls()
tarinfo.buf = buf
@@ -831,7 +842,7 @@
tarinfo.gid = nti(buf[116:124])
tarinfo.size = nti(buf[124:136])
tarinfo.mtime = nti(buf[136:148])
- tarinfo.chksum = nti(buf[148:156])
+ tarinfo.chksum = chksum
tarinfo.type = buf[156:157]
tarinfo.linkname = buf[157:257].rstrip(NUL)
tarinfo.uname = buf[265:297].rstrip(NUL)
@@ -843,8 +854,6 @@
if prefix and not tarinfo.issparse():
tarinfo.name = prefix + "/" + tarinfo.name
- if tarinfo.chksum not in calc_chksums(buf):
- raise ValueError("invalid header")
return tarinfo
def tobuf(self, posix=False):
@@ -1793,16 +1802,14 @@
tarinfo = self.proc_member(tarinfo)
- except ValueError, e:
+ except HeaderError, e:
if self.ignore_zeros:
- self._dbg(2, "0x%X: empty or invalid block: %s" %
- (self.offset, e))
+ self._dbg(2, "0x%X: %s" % (self.offset, e))
self.offset += BLOCKSIZE
continue
else:
if self.offset == 0:
- raise ReadError("empty, unreadable or compressed "
- "file: %s" % e)
+ raise ReadError(str(e))
return None
break