From 9e99d10c9a7fc20adb0009d3761fe3cdfdbe0a8c Mon Sep 17 00:00:00 2001 From: Alan Modra Date: Thu, 7 Sep 2023 08:43:53 +0930 Subject: [PATCH] PR30828, notes obstack memory corruption Commit 3bab069c29b3 carelessly allowed "string" to be released from the notes obstack twice, with the second call to obstack_free releasing memory for a fixup that just happened to be the same size as the original string. The fixup then of course was overwritten. This patch fixes that problem, and another that could occur on an error path. PR 30828 * stabs.c (s_stab_generic): Don't free string twice. Don't blow away entire notes obstack on a missing string. --- gas/stabs.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/gas/stabs.c b/gas/stabs.c index 1b25542900a..0c8022fb2cb 100644 --- a/gas/stabs.c +++ b/gas/stabs.c @@ -262,7 +262,7 @@ s_stab_generic (int what, { as_warn (_(".stab%c: missing string"), what); ignore_rest_of_line (); - goto out; + goto out2; } /* FIXME: We should probably find some other temporary storage for string, rather than leaking memory if someone else @@ -350,7 +350,10 @@ s_stab_generic (int what, This must be done before creating symbols below, which uses the notes obstack. */ if (saved_string_obstack_end == obstack_next_free (¬es)) - obstack_free (¬es, string); + { + obstack_free (¬es, string); + saved_string_obstack_end = NULL; + } /* At least for now, stabs in a special stab section are always output as 12 byte blocks of information. */ @@ -398,6 +401,7 @@ s_stab_generic (int what, out: if (saved_string_obstack_end == obstack_next_free (¬es)) obstack_free (¬es, string); + out2: subseg_set (saved_seg, saved_subseg); } -- 2.30.2