diff options
author | Dr. Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> | 2018-10-20 16:53:09 +0200 |
---|---|---|
committer | Dr. Matthias St. Pierre <Matthias.St.Pierre@ncp-e.com> | 2018-10-22 14:54:55 +0200 |
commit | 5b4cb385c18a5bb4e118e300f1c746bf7c2a5628 (patch) | |
tree | 825a25f217a939e86d424cae221dd60987099f20 | |
parent | d8cac50b023be249cdaba054f43acecf17025ce4 (diff) |
RAND_add(): fix heap corruption in error path
This bug was introduced by #7382 which enhanced RAND_add() to
accept large buffer sizes. As a consequence, RAND_add() now fails
for buffer sizes less than 32 bytes (i.e. less than 256 bits).
In addition, rand_drbg_get_entropy() forgets to reset the attached
drbg->pool in the case of an error, which leads to the heap corruption.
The problem occurred with RAND_load_file(), which reads the file in
chunks of 1024 bytes each. If the size of the final chunk is less than
32 bytes, then RAND_add() fails, whence RAND_load_file() fails
silently for buffer sizes n = k * 1024 + r with r = 1,...,31.
This commit fixes the heap corruption only. The other issues will
be addressed in a separate pull request.
Thanks to Gisle Vanem for reporting this issue.
Fixes #7449
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/7455)
-rw-r--r-- | crypto/rand/rand_lib.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/crypto/rand/rand_lib.c b/crypto/rand/rand_lib.c index f40c513ce8..e6fcbce7fd 100644 --- a/crypto/rand/rand_lib.c +++ b/crypto/rand/rand_lib.c @@ -200,6 +200,10 @@ size_t rand_drbg_get_entropy(RAND_DRBG *drbg, } err: + /* we need to reset drbg->pool in the error case */ + if (ret == 0 && drbg->pool != NULL) + drbg->pool = NULL; + rand_pool_free(pool); return ret; } |