Hey folks, any response on this? > Hello, > > I've bumped into strange tar behavior - it's unable to decompress a > previously compressed archive: > > % file test.tar.gz > test.tar.gz: gzip compressed data, from Unix, last modified: Fri Dec 21 > 13:00:50 2012 > % tar -xf test.tar.gz -C out && echo "Success" > tar: This does not look like a tar archive > tar: Exiting with failure status due to previous errors > % tar -xf test.tar.gz && echo "Success" > Success > > Here's the content of the file. In contains nothing but an empty directory: > % cat test.tar.gz | base64 > H4sIAFIz1FAAA+3PMQqDQBCF4TnK3sAZddzjiAERCaywccn1NUUghWgjqf6vecW84s2cl/Re8nPM > /WsdpjlNldxNdzH6Jy26/uaXWK2da2Nem6i1rXUS/PYlB8r+dg5ByqOktZz0Lu4AAAAAAAAAAAAA > AAAAAPzRBndnEVwAKAAA > > I've made a quick research and found out that src/list.c:tar_checksum function > wrongly interprets this file as a plain tar archive instead of gzipped tar due > checksum collision (signed_sum == recorded_sum == 0): > > (gdb) run -xvf ../iw.tgz.bak > Starting program: /home/m0use/work/tar-bug/tar/src/tar -xvf ../iw.tgz.bak > warning: Could not load shared library symbols for linux-vdso.so.1. > Do you need "set solib-search-path" or "set sysroot"? > > Breakpoint 1, tar_checksum (header=<optimized out>, silent=silent@entry=true) > at list.c:350 > 350 if (unsigned_sum != recorded_sum && signed_sum != recorded_sum) > (gdb) p signed_sum > $1 = 0 > (gdb) p recorded_sum > $2 = 0 > > So, tar_checksum function returns HEADER_SUCCESS in case of gzipped tar file, > what's wrong. > Here's a couple of patches which fixes the case from my perspective. > Please, review when you have a chance. > Thanks! > > > Alexander Kolesen (2): > check_compressed_archive: check for compressed signatures first prior > to checking tar checksum > init_buffer: zero-fill allocated memory to prevent examing a junk > > src/buffer.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-)
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