From c4eec0c16b02c97a62a95b6a08656c3a9ddb6baa Mon Sep 17 00:00:00 2001 From: Adam Langley Date: Mon, 29 Feb 2016 08:01:05 -0800 Subject: [PATCH] Fix encoding bug in i2c_ASN1_INTEGER MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit (Imported from upstream's 3661bb4e7934668bd99ca777ea8b30eedfafa871.) Fix bug where i2c_ASN1_INTEGER mishandles zero if it is marked as negative. Thanks to Huzaifa Sidhpurwala and Hanno Böck for reporting this issue. BUG=590615 Change-Id: I8959e8ae01510a5924862a3f353be23130eee554 Reviewed-on: https://boringssl-review.googlesource.com/7199 Reviewed-by: David Benjamin --- crypto/asn1/a_int.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/crypto/asn1/a_int.c b/crypto/asn1/a_int.c index 9790779a..38a01bcb 100644 --- a/crypto/asn1/a_int.c +++ b/crypto/asn1/a_int.c @@ -124,6 +124,8 @@ int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) else { ret = a->length; i = a->data[0]; + if (ret == 1 && i == 0) + neg = 0; if (!neg && (i > 127)) { pad = 1; pb = 0; @@ -162,7 +164,7 @@ int i2c_ASN1_INTEGER(ASN1_INTEGER *a, unsigned char **pp) p += a->length - 1; i = a->length; /* Copy zeros to destination as long as source is zero */ - while (!*n) { + while (!*n && i > 1) { *(p--) = 0; n--; i--;