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| author | Nick Mathewson <nickm@torproject.org> | 2015-11-25 10:30:58 -0500 |
|---|---|---|
| committer | Nick Mathewson <nickm@torproject.org> | 2015-11-25 22:29:59 -0500 |
| commit | dedea28c2ef59eb86f5d9704e5609ae13fa8b3c2 (patch) | |
| tree | 92ddba2410a8a80aad28734be47c78c460bbd6e6 /src/common | |
| parent | 232ccc18c40f0d0302b2e21b0f67885c548f8e63 (diff) | |
| download | tor-dedea28c2ef59eb86f5d9704e5609ae13fa8b3c2.tar.gz tor-dedea28c2ef59eb86f5d9704e5609ae13fa8b3c2.zip | |
Make crypto_seed_rng() and crypto_rand() less scary.
These functions must really never fail; so have crypto_rand() assert
that it's working okay, and have crypto_seed_rng() demand that
callers check its return value. Also have crypto_seed_rng() check
RAND_status() before returning.
Diffstat (limited to 'src/common')
| -rw-r--r-- | src/common/compat.h | 2 | ||||
| -rw-r--r-- | src/common/crypto.c | 10 | ||||
| -rw-r--r-- | src/common/crypto.h | 3 |
3 files changed, 10 insertions, 5 deletions
diff --git a/src/common/compat.h b/src/common/compat.h index c7c468c754..c3d6abd07c 100644 --- a/src/common/compat.h +++ b/src/common/compat.h @@ -118,6 +118,7 @@ #define ATTR_CONST __attribute__((const)) #define ATTR_MALLOC __attribute__((malloc)) #define ATTR_NORETURN __attribute__((noreturn)) +#define ATTR_WUR __attribute__((warn_unused_result)) /* Alas, nonnull is not at present a good idea for us. We'd like to get * warnings when we pass NULL where we shouldn't (which nonnull does, albeit * spottily), but we don't want to tell the compiler to make optimizations @@ -153,6 +154,7 @@ #define ATTR_NORETURN #define ATTR_NONNULL(x) #define ATTR_UNUSED +#define ATTR_WUR #define PREDICT_LIKELY(exp) (exp) #define PREDICT_UNLIKELY(exp) (exp) #endif diff --git a/src/common/crypto.c b/src/common/crypto.c index 815c2ec0c5..b7dc4b86af 100644 --- a/src/common/crypto.c +++ b/src/common/crypto.c @@ -2358,7 +2358,7 @@ crypto_seed_rng(void) memwipe(buf, 0, sizeof(buf)); - if (rand_poll_ok || load_entropy_ok) + if ((rand_poll_ok || load_entropy_ok) && RAND_status() == 1) return 0; else return -1; @@ -2380,12 +2380,14 @@ int crypto_rand_unmocked(char *to, size_t n) { int r; + if (n == 0) + return 0; + tor_assert(n < INT_MAX); tor_assert(to); r = RAND_bytes((unsigned char*)to, (int)n); - if (r == 0) - crypto_log_errors(LOG_WARN, "generating random data"); - return (r == 1) ? 0 : -1; + tor_assert(r >= 0); + return 0; } /** Return a pseudorandom integer, chosen uniformly from the values diff --git a/src/common/crypto.h b/src/common/crypto.h index 6256f7346b..d2ced63bd5 100644 --- a/src/common/crypto.h +++ b/src/common/crypto.h @@ -16,6 +16,7 @@ #include <stdio.h> #include "torint.h" #include "testsupport.h" +#include "compat.h" /* Macro to create an arbitrary OpenSSL version number as used by @@ -258,7 +259,7 @@ int crypto_expand_key_material_rfc5869_sha256( uint8_t *key_out, size_t key_out_len); /* random numbers */ -int crypto_seed_rng(void); +int crypto_seed_rng(void) ATTR_WUR; MOCK_DECL(int,crypto_rand,(char *to, size_t n)); int crypto_rand_unmocked(char *to, size_t n); int crypto_strongest_rand(uint8_t *out, size_t out_len); |