From 93c774d482694643cafbc82578ac8b729fb5bc8b Mon Sep 17 00:00:00 2001 From: Cyrill Gorcunov Date: Wed, 4 Nov 2020 13:08:06 +0300 Subject: [PATCH] BR3392637: output/outieee: Fix nil dereference The handling been broken in commit 98578071. Upstream-Status: Backport [https://github.com/netwide-assembler/nasm/commit/93c774d482694643cafbc82578ac8b729fb5bc8b] CVE: CVE-2020-21528 Signed-off-by: Cyrill Gorcunov Signed-off-by: Archana Polampalli --- output/outieee.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/output/outieee.c b/output/outieee.c index bff2f085..b3ccc5f6 100644 --- a/output/outieee.c +++ b/output/outieee.c @@ -795,6 +795,23 @@ static int32_t ieee_segment(char *name, int *bits) define_label(name, seg->index + 1, 0L, false); ieee_seg_needs_update = NULL; + /* + * In commit 98578071b9d71ecaa2344dd9c185237c1765041e + * we reworked labels significantly which in turn lead + * to the case where seg->name = NULL here and we get + * nil dereference in next segments definitions. + * + * Lets placate this case with explicit name setting + * if labels engine didn't set it yet. + * + * FIXME: Need to revisit this moment if such fix doesn't + * break anything but since IEEE 695 format is veeery + * old I don't expect there are many users left. In worst + * case this should only lead to a memory leak. + */ + if (!seg->name) + seg->name = nasm_strdup(name); + if (seg->use32) *bits = 32; else -- 2.40.0