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Building with GCC 7 produces an error building rpcgen: rpc_parse.c: In function 'get_prog_declaration': rpc_parse.c:543:25: error: may write a terminating nul past the end of the destination [-Werror=format-length=] sprintf (name, "%s%d", ARGNAME, num); /* default name of argument */ ~~~~^ rpc_parse.c:543:5: note: format output between 5 and 14 bytes into a destination of size 10 sprintf (name, "%s%d", ARGNAME, num); /* default name of argument */ ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ That buffer overrun is for the case where the .x file declares a program with a million arguments. The strcpy two lines above can generate a buffer overrun much more simply for a long argument name. The limit on length of line read by rpcgen (MAXLINESIZE == 1024) provides a bound on the buffer size needed, so this patch just changes the buffer size to MAXLINESIZE to avoid both possible buffer overruns. A testcase is added that rpcgen does not crash with a 500-character argument name, where it previously crashed. It would not at all surprise me if there are many other ways of crashing rpcgen with either valid or invalid input; fuzz testing would likely find various such bugs, though I don't think they are that important to fix (rpcgen is not that likely to be used with untrusted .x files as input). (As well as fuzz-findable bugs there are probably also issues when various int variables get overflowed on very large input.) The test infrastructure for rpcgen-not-crashing tests would need extending if tests are to be added for cases where rpcgen should produce an error, as opposed to cases where it should succeed. Tested for x86_64 and x86. [BZ #20790] * sunrpc/rpc_parse.c (get_prog_declaration): Increase buffer size to MAXLINESIZE. * sunrpc/bug20790.x: New file. * sunrpc/Makefile [$(run-built-tests) = yes] (rpcgen-tests): New variable. [$(run-built-tests) = yes] (tests-special): Add $(rpcgen-tests). [$(run-built-tests) = yes] ($(rpcgen-tests)): New rule.
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566 B
Plaintext
2 lines
566 B
Plaintext
program TPROG { version TVERS { int FUNC(int aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa) = 1; } = 1; } = 1;
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