I'm currently trying to reverse engineer the firmware for the Swann DVR16-4500 security camera system. I successfully extracted the cramfs filesystem and now I have the following files inside the cramfs-root directory:
-rw-r--r-- 1 root root 2289232 Dec 31 1969 gui_res.tar.lzma
-rwxr-xr-x 1 root root 744 Dec 31 1969 new_10.bin
drwxr-xr-x 2 root root 4096 Dec 15 2015 Player_ml
-rwxr-xr-x 1 root root 824944 Dec 31 1969 player.zip
-rwxr-xr-x 1 root root 2936 Dec 31 1969 start.sh
-rw-r--r-- 1 root root 6213824 Dec 31 1969 sys_app.tar.lzma
-rwxr-xr-x 1 root root 3585544 Dec 31 1969 uImage
-rwxr-xr-x 1 root root 1881320 Dec 31 1969 WebComponents.exe
-rwxr-xr-x 1 root root 689296 Dec 31 1969 webs.tar.lzma
I tried using unlzma and tar --lzma -xvf to extract the *.tar.lzma files, but I had no luck. I came across this post which suggested running the kernel in an emulator in the hopes of finding the necessary extraction tools there. I've been tearing through QEMU documentation and online videos but I can't figure out exactly what I need to do to get QEMU to run the uImage kernel using qemu-system-arm. What do I need to do in order to get the kernel to run?
tar --lzma xvf <file>? Were there error messages? What was the output? Did you run thefilecommand against the*.tar.lzmafiles? If so, what were the results, and were the results manually verified? Did you inspect a hex dump of any of the*.tar.lzmafiles? If so what were the results?filesay onuImage?tar --lzma xvfI get the following response:xz: (stdin): File format not recognized tar: Child returned status 1 tar: Error is not recoverable: exiting nowthe file command just says all of the files are "data". When I run lzmainfo the command is satisfied that it is an lzma file, but it says that the file will be over a petabyte when it's uncompressed, similar to the post I referenced above. `.tar.xzand.tar.lzma... and in fact the man page strongly suggests that the resulting archive is filtered throughxzorlzmarespectively, although both use LZMA as the compression algorithm. Also, do you havexzinstalled?xzdecorxz-utilson Debian/Ubuntu.