diff options
| author | Paul Dreik <github@pauldreik.se> | 2019-11-29 19:23:35 +0100 |
|---|---|---|
| committer | Tomas Mraz <tomas@openssl.org> | 2021-08-25 17:02:37 +0200 |
| commit | 0760d132da046063f6ac3c28bd2ee1d8505e6fcd (patch) | |
| tree | 108e4cbf6d695337bcb35a4820356b81b4de937f | |
| parent | 562d4cd3c35b32f2bc6ac0770b80ce394f8d76a4 (diff) | |
Avoid invoking memcpy if size is zero or the supplied buffer is NULL
This allows for passing a NULL pointer with zero max_len.
Invoking memcpy on NULL is undefined behaviour, even if the size is zero.
https://en.cppreference.com/w/c/string/byte/memcpy
The function can now be queried for the necessary buffer length.
Reviewed-by: Paul Dale <pauli@openssl.org>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/10541)
| -rw-r--r-- | crypto/asn1/evp_asn1.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/crypto/asn1/evp_asn1.c b/crypto/asn1/evp_asn1.c index 3122c4724f..13d8ed3893 100644 --- a/crypto/asn1/evp_asn1.c +++ b/crypto/asn1/evp_asn1.c @@ -27,7 +27,10 @@ int ASN1_TYPE_set_octetstring(ASN1_TYPE *a, unsigned char *data, int len) return 1; } -/* int max_len: for returned value */ +/* int max_len: for returned value + * if passing NULL in data, nothing is copied but the necessary length + * for it is returned. + */ int ASN1_TYPE_get_octetstring(const ASN1_TYPE *a, unsigned char *data, int max_len) { int ret, num; @@ -43,7 +46,8 @@ int ASN1_TYPE_get_octetstring(const ASN1_TYPE *a, unsigned char *data, int max_l num = ret; else num = max_len; - memcpy(data, p, num); + if (num > 0 && data != NULL) + memcpy(data, p, num); return ret; } |