Package: lzma Version: 25.00+dfsg-1 Control: found -1 24.08+dfsg-2 Control: affects -1 depthcharge-tools X-Debbugs-CC: [email protected]
Hi, The lzma executable from the lzma package (vs. xz-utils) returns zero exit status when decompressing some files not compressed by lzma, even when such decompression results in no output. The specific case I'm interested in is: $ lzma -dc "/boot/vmlinuz-$(uname -r)"; echo $? 0 $ lzma -t "/boot/vmlinuz-$(uname -r)" && echo "yes" yes It looks like it's about zeros: $ head -c18 "/boot/vmlinuz-$(uname -r)" | xxd 00000000: 4d5a 0000 0000 0000 0000 0000 0000 0000 MZ.............. 00000010: 0000 .. # fails with -c17 $ head -c18 "/boot/vmlinuz-$(uname -r)" | lzma -d; echo $? 0 $ head -c18 "/dev/zero" | lzma -d; echo $? 0 I'm not sure if this is actually a valid lzma file, but xz and zstd (with their lzma support) seem to reject it as I expected lzma should: $ xz --format=lzma -dc "/boot/vmlinuz-$(uname -r)"; echo $? xz: /boot/vmlinuz-7.1.8+deb14.1-amd64: File format not recognized 1 # --format=* doesn't seem to take effect here, but still $ zstd --format=lzma -dc "/boot/vmlinuz-$(uname -r)"; echo $? zstd: /boot/vmlinuz-7.1.8+deb14.1-amd64: unsupported format 1 I was using the exit status with many decompressors to get the actual kernel file from a potentially unknown-compressed file so I can do bootloader stuff in depthcharge-tools, I'll have to actually check the decompressed size for robustness... -- System Information: Debian Release: forky/sid APT prefers buildd-unstable APT policy: (500, 'buildd-unstable'), (500, 'unstable'), (1, 'experimental') Architecture: amd64 (x86_64) Foreign Architectures: arm64, armhf, i386 Kernel: Linux 7.1.8+deb14.1-amd64 (SMP w/8 CPU threads; PREEMPT) Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8), LANGUAGE=en_GB:en Shell: /bin/sh linked to /usr/bin/dash Init: systemd (via /run/systemd/system) LSM: AppArmor: enabled Versions of packages lzma depends on: ii libc6 2.43-3 ii libgcc-s1 16.2.0-1 ii libstdc++6 16.2.0-1 lzma recommends no packages. lzma suggests no packages. -- no debconf information
