When OpenSSL is configured using `--with-rand-seed=devrandom`, the preprocessor
reports the following error
crypto/info.c:104:66: error:
macro "add_seeds_stringlist" passed 3 arguments, but takes just 2
add_seeds_stringlist("random-device", { DEVRANDOM, NULL });
The reason why the preprocessor complains about three arguments being passed
is that according to [1], balanced braces in macro arguments don't prevent the
comma from acting as an argument separator:
3.3 Macro Arguments
...
Parentheses within each argument must balance;
a comma within such parentheses does not end the argument.
However, there is no requirement for square brackets or braces to balance,
and they do not prevent a comma from separating arguments.
Also introduced an iteration pointer `p`, because `dev` is not an lvalue:
crypto/info.c:78:41: error:
lvalue required as increment operand
for (; *dev != NULL; dev++) {
[1] https://gcc.gnu.org/onlinedocs/cpp/Macro-Arguments.html
Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10762)
do { \
add_seeds_string(label "("); \
{ \
do { \
add_seeds_string(label "("); \
{ \
- const char *dev[] = strlist; \
+ const char *dev[] = { strlist, NULL }; \
+ const char **p; \
- for (; *dev != NULL; dev++) { \
+ for (p = dev; *p != NULL; p++) { \
if (!first) \
OPENSSL_strlcat(seeds, " ", sizeof(seeds)); \
first = 0; \
if (!first) \
OPENSSL_strlcat(seeds, " ", sizeof(seeds)); \
first = 0; \
- OPENSSL_strlcat(seeds, *dev, sizeof(seeds)); \
+ OPENSSL_strlcat(seeds, *p, sizeof(seeds)); \
} \
} \
OPENSSL_strlcat(seeds, ")", sizeof(seeds)); \
} \
} \
OPENSSL_strlcat(seeds, ")", sizeof(seeds)); \
add_seeds_string("getrandom-syscall");
#endif
#ifdef OPENSSL_RAND_SEED_DEVRANDOM
add_seeds_string("getrandom-syscall");
#endif
#ifdef OPENSSL_RAND_SEED_DEVRANDOM
- add_seeds_stringlist("random-device", { DEVRANDOM, NULL });
+ add_seeds_stringlist("random-device", DEVRANDOM);
#endif
#ifdef OPENSSL_RAND_SEED_EGD
#endif
#ifdef OPENSSL_RAND_SEED_EGD
- add_seeds_stringlist("EGD", { DEVRANDOM_EGD, NULL });
+ add_seeds_stringlist("EGD", DEVRANDOM_EGD);
#endif
#ifdef OPENSSL_RAND_SEED_OS
add_seeds_string("os-specific");
#endif
#ifdef OPENSSL_RAND_SEED_OS
add_seeds_string("os-specific");