From 4b7d9cd4a018898d7714ce06f3faf2626c14582b Mon Sep 17 00:00:00 2001 From: Werner Koch Date: Wed, 5 Oct 2022 14:19:06 +0200 Subject: [PATCH] Detect a possible overflow directly in the TLV parser. * src/ber-help.c (_ksba_ber_read_tl): Check for overflow of a commonly used sum. -- It is quite common to have checks like if (ti.nhdr + ti.length >= DIM(tmpbuf)) return gpg_error (GPG_ERR_TOO_LARGE); This patch detects possible integer overflows immmediately when creating the TI object. Reported-by: ZDI-CAN-18927, ZDI-CAN-18928, ZDI-CAN-18929 Upstream-Status: Backport [https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libksba.git;a=patch;h=4b7d9cd4a018898d7714ce06f3faf2626c14582b] CVE: CVE-2022-3515 Signed-off-by: Chee Yang Lee --- src/ber-help.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/src/ber-help.c b/src/ber-help.c index 81c31ed..56efb6a 100644 --- a/src/ber-help.c +++ b/src/ber-help.c @@ -182,6 +182,12 @@ _ksba_ber_read_tl (ksba_reader_t reader, struct tag_info *ti) ti->length = len; } + if (ti->length > ti->nhdr && (ti->nhdr + ti->length) < ti->length) + { + ti->err_string = "header+length would overflow"; + return gpg_error (GPG_ERR_EOVERFLOW); + } + /* Without this kludge some example certs can't be parsed */ if (ti->class == CLASS_UNIVERSAL && !ti->tag) ti->length = 0; -- 2.11.0