Package: cnews
Version: cr.g7-37
Severity: critical
Justification: causes serious data loss
I just stumbled upon this bug in newsrun, which has caused some lost
newsbatches for me.
Lets say you have multiple newsfeeds via UUCP, using different
compression methods (e.g. compress and gzip). As incoming newsbatches
are processed by rnews, they are given temporary filenames in
/var/spool/news/in.coming, consisting of an timestamp and an suffix
denoting the compression method. These suffixes are ".t" for
"uncompressed", ".z" for "compressed using gzip", ".Z" for "compressed
using compress" and so on. Two batches coming in at the same time (such
as when polling multiple systems in parallel) and differing only in the
compression method will thus get an filename differing only in the
suffix, e.g. "12345678.z" and "12345678.Z" (note the case of the
suffix).
/usr/lib/news/input/newsrun is then run by cron and in a first stage
decompresses all compressed newsbatches. This is done by the following
lines of code (line 124 ff.):
--------- by cutting here you might damage your screen surface ---------
[...]
# Decompress if necessary.
case $f in
*.Z) text=`echo $f | sed 's/Z\$/t/'`
uncompress <$f >$text
;;
*.z) text=`echo $f | sed 's/z\$/t/'`
gzip -dc <$f >$text
;;
[and so on]
--------- by cutting here you might damage your screen surface ---------
As one can see, an batch named "12345678.Z" is decompressed into
"12345678.t". An batch named "12345678.z" is _also_ decompressed into
"12345678.t". Depending on which one is picked up first, one of the two
batches _will_ be lost irrevocabily.
A possible solution would be to change the sed command to alter the
timestamp also, amending a letter just before the suffix ".t". As no two
compressed batches with the same timestamp and suffix will be created by
rnews, this should be a reasonable safeguard.
(This bug must have lingered in CNews for about a decade now. Is it
really possible that I am the first person to stumble upon it?)
Greetings from Telgte,
=ToJe=
-- System Information:
Debian Release: 3.1
APT prefers unstable
APT policy: (990, 'unstable')
Architecture: i386 (i586)
Kernel: Linux 2.4.29
Locale: [EMAIL PROTECTED], [EMAIL PROTECTED] (charmap=ISO-8859-15)
Versions of packages cnews depends on:
ii cron 3.0pl1-87 management of regular background p
ii debconf [debconf-2.0] 1.4.47 Debian configuration management sy
ii libc6 2.3.2.ds1-20 GNU C Library: Shared libraries an
ii perl 5.8.4-8 Larry Wall's Practical Extraction
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