strlcat and strlcpy break Samba configure about honggfuzz

[douglasbagnall]

So, of course, what I missed is the configure test is checking for library symbols, while the compilation is failing on the functions not being declared in the source code. That is, Samba's configure is using the linkability of strlcpy and strlcat as a proxy for the necessity of adding #include <bsd/string.h>. That's wrong.

OTOH, I think Honggfuzz might be slightly treading new ground here. I'm guessing normally if you have those symbols in the system library, you have them in system headers, as per https://man.freebsd.org/cgi/man.cgi?query=strlcpy&sektion=3?

hfuzz_cc/hfuzz-clang -D_SAMBA_BUILD_=4 -DHAVE_CONFIG_H=1 -MMD -D_GNU_SOURCE=1 -D_XOPEN_SOURCE_EXTENDED=1 -I. -I../.. -I. -I../.. ../../test.c -c -osamba-fuzz/bin/.conf_check_cfeb54db47c3c14d04c387915dd5ff43/testbuild/default/test.c.1.o
hfuzz-clang test.c.1.o -osamba-fuzz/bin/.conf_check_cfeb54db47c3c14d04c387915dd5ff43/testbuild/default/testprog -Wl,-Bstatic -Wl,-Bdynamic -L/usr/local/lib

vs

hfuzz-clang -D_SAMBA_BUILD_=4 -DHAVE_CONFIG_H=1 -MMD -D_GNU_SOURCE=1 -D_XOPEN_SOURCE_EXTENDED=1 -DHAVE_CONFIG_H=1 -D_SAMBA_HOSTCC_ -DDEVELOPER -DDEBUG_PASSWORD -fPIC -D__STDC_WANT_LIB_EXT1__=1 -D_REENTRANT -DDEVELOPER -DDEBUG_PASSWORD -fstack-protector-strong -fstack-clash-protection -g -g -Wall -Wshadow -Wmissing-prototypes -Wmissing-field-initializers -Wformat-zero-length -Wcast-align -Wcast-qual -fno-common -Werror=address -Werror=strict-prototypes -Wstrict-prototypes -Werror=write-strings -Wwrite-strings -Werror-implicit-function-declaration -Werror=implicit-int -Werror=pointer-arith -Wpointer-arith -Werror=declaration-after-statement -Wdeclaration-after-statement -Werror=return-type -Wreturn-type -Werror=uninitialized -Wuninitialized -Wimplicit-fallthrough -Werror=strict-overflow -Wstrict-overflow=2 -Werror=old-style-definition -Wold-style-definition -Wformat=2 -Wno-format-y2k -Wno-format-zero-length -Werror=format-security -Wformat-security -Werror=format -DSTATIC_LIBREPLACE_HOSTCC_MODULES=NULL -DSTATIC_LIBREPLACE_HOSTCC_MODULES_PROTO=extern void __LIBREPLACE_HOSTCC_dummy_module_proto(void) -Ilib/replace -I../../lib/replace -Iinclude/public -I../../include/public -Isource4 -I../../source4 -Ilib -I../../lib -Isource4/lib -I../../source4/lib -Isource4/include -I../../source4/include -Iinclude -I../../include -I. -I../.. ../../lib/replace/replace.c -c -osamba-fuzz/bin/default/lib/replace/replace.c.1.o

../../lib/replace/replace.c:837:3: error: implicit declaration of function 'strlcpy' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
                strlcpy(buf, s, buflen);

[robertswiecki]

Hi,

IMO, this is a more preprocessing error, than anything related to compilation. hfuzz-clang changes some compilation options, but rather nothing related to inclusion of headers, and it seems that replace.c simply is missing some header?

As in, hfuzz-clang during the linking stage is providing its own weak symbols for strlcpy and such, but this error looks like something happening at compilation stage.

Maybe if you removed this https://github.com/google/honggfuzz/blob/master/hfuzz_cc/hfuzz-cc.c#L366C5-L366C5 it will start working?

[douglasbagnall]

Yes, I also came to the conclusion it was a bug in the Samba build assumptions, to be fixed with something like
https://gitlab.com/samba-team/devel/samba/-/commit/ed7383cad34d84abca8c15dae8746ccafada0051

So I haven't tried this:

Maybe if you removed this https://github.com/google/honggfuzz/blob/master/hfuzz_cc/hfuzz-cc.c#L366C5-L366C5 it will start working?

as the Samba patch works.

Thanks.