From 71ae0c724dd49d493621b367d17079f8cc70443c Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 20 Apr 2013 14:07:01 -0400 Subject: [PATCH] comment potentially-confusing use of struct crypt_data type --- src/crypt/crypt.c | 7 ++++++- src/crypt/crypt_r.c | 4 ++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/src/crypt/crypt.c b/src/crypt/crypt.c index f1e310f6..46500737 100644 --- a/src/crypt/crypt.c +++ b/src/crypt/crypt.c @@ -5,7 +5,12 @@ char *__crypt_r(const char *, const char *, struct crypt_data *); char *crypt(const char *key, const char *salt) { - /* Note: update this size when we add more hash types */ + /* This buffer is sufficiently large for all + * currently-supported hash types. It needs to be updated if + * longer hashes are added. The cast to struct crypt_data * is + * purely to meet the public API requirements of the crypt_r + * function; the implementation of crypt_r uses the object + * purely as a char buffer. */ static char buf[128]; return __crypt_r(key, salt, (struct crypt_data *)buf); } diff --git a/src/crypt/crypt_r.c b/src/crypt/crypt_r.c index 3257e8b9..5982c4c9 100644 --- a/src/crypt/crypt_r.c +++ b/src/crypt/crypt_r.c @@ -11,6 +11,10 @@ char *__crypt_sha512(const char *, const char *, char *); char *__crypt_r(const char *key, const char *salt, struct crypt_data *data) { + /* Per the crypt_r API, the caller has provided a pointer to + * struct crypt_data; however, this implementation does not + * use the structure to store any internal state, and treats + * it purely as a char buffer for storing the result. */ char *output = (char *)data; if (salt[0] == '$' && salt[1] && salt[2]) { if (salt[1] == '1' && salt[2] == '$')