From 9024676102cbd24d08f41fa3de7761d64f13db4d Mon Sep 17 00:00:00 2001 From: Tom Yu Date: Tue, 7 Apr 2009 21:22:20 +0000 Subject: [PATCH] CVE-2009-0847 asn1buf_imbed incorrect length validation asn1buf_imbed() can perform pointer arithmetic that causes the "bound" pointer of the subbuffer to be less than the "next" pointer. This can lead to malloc() failure or crash. In asn1buf_imbed(), check the length before doing arithmetic to set subbuf->bound. In asn1buf_remove_octetstring() and asn1buf_remove_charstring(), check for invalid buffer pointers before executing an unsigned length check against a (casted to size_t) negative number. ticket: 6444 tags: pullup target_version: 1.7 git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@22175 dc483132-0cff-0310-8789-dd5450dbe970 --- src/lib/krb5/asn.1/asn1buf.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/src/lib/krb5/asn.1/asn1buf.c b/src/lib/krb5/asn.1/asn1buf.c index 5793a0303..8985140d4 100644 --- a/src/lib/krb5/asn.1/asn1buf.c +++ b/src/lib/krb5/asn.1/asn1buf.c @@ -92,11 +92,11 @@ asn1_error_code asn1buf_wrap_data(asn1buf *buf, const krb5_data *code) asn1_error_code asn1buf_imbed(asn1buf *subbuf, const asn1buf *buf, const unsigned int length, const int indef) { + if (buf->next > buf->bound + 1) return ASN1_OVERRUN; subbuf->base = subbuf->next = buf->next; if (!indef) { + if (length > (size_t)(buf->bound + 1 - buf->next)) return ASN1_OVERRUN; subbuf->bound = subbuf->base + length - 1; - if (subbuf->bound > buf->bound) - return ASN1_OVERRUN; } else /* constructed indefinite */ subbuf->bound = buf->bound; return 0; @@ -205,6 +205,7 @@ asn1_error_code asn1buf_remove_octetstring(asn1buf *buf, const unsigned int len, { unsigned int i; + if (buf->next > buf->bound + 1) return ASN1_OVERRUN; if (len > (size_t)(buf->bound + 1 - buf->next)) return ASN1_OVERRUN; if (len == 0) { *s = 0; @@ -223,6 +224,7 @@ asn1_error_code asn1buf_remove_charstring(asn1buf *buf, const unsigned int len, { unsigned int i; + if (buf->next > buf->bound + 1) return ASN1_OVERRUN; if (len > (size_t)(buf->bound + 1 - buf->next)) return ASN1_OVERRUN; if (len == 0) { *s = 0; -- 2.26.2