Basic compartmentalization for tcpdump #2447
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The version now comes from the PACKAGE_VERSION macro. Fixes: 0a7e5f1 ("tcpdump: Update to 4.99.5")
This macro was replaced by a collection of architecture ifdefs in tcpdump 4.99.4 (commit 51a1830) so defining it does nothing.
Due to the use of a linked list pointer at the beginning of the object, the bounds won't be exact in some cases without a refactor to separate the linked list from the allocation, but this is quick and easy.
Split SRCS entries into core bits of tcpdump, core bits of the dissection framework, and individual dissectors.
This mirrors an internal split in upstream to enable compartmentlization. We differ slightly from upstream in that we keep addrtoname.c in tcpdump due to its use of casper for DNS lookups. Likewise machdep.c is only used by tcpdump.
Each set of dissectors (as indicated by a separate print-*.c file) goes in its own compartment (with utilities added manually in a few cases). Most of the rest go an the default compartment except for a manual compartment for MD5 signature verification.
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Having done the compartmentalization via a library, I'm not sure it was the right approach. It's a mess in the build system and while the split needs to be there, it could just be in the policy file. |
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I took the libnetdissect used internally in tcpdump's build and inspired by our early compartmentalization work and then added sub-library compartments. We'll need to audit the result to see what linkage surprises there are, but it's a start.