From: Nick Clifton <nickc@redhat.com>
To: jeffreyalaw@gmail.com
Cc: gcc-patches@gcc.gnu.org
Subject: RFA: Another Rust demangler recursion limit
Date: Fri, 01 Jul 2022 16:12:45 +0100 [thread overview]
Message-ID: <87y1xcn9xu.fsf@redhat.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 606 bytes --]
Hi Jeff,
[I am sending this to your directly since you seem to be the only one
reviewing these patches].
Hot on the heels of the fix for the recursion problem in demangle_const
a binutils user has filed another PoC that exposes a problem in
demangle_path_maybe_open_generics():
https://sourceware.org/bugzilla/show_bug.cgi?id=29312#c1
I have redirected them to file a bug report with the gcc system, but in
the hopes of getting a fix in quickly I am also attaching a patch
here. It just does the obvious thing of adding a recursion counter
and limit to the function.
Cheers
Nick
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: rust-demangle.c.patch --]
[-- Type: text/x-patch, Size: 911 bytes --]
diff --git a/libiberty/rust-demangle.c b/libiberty/rust-demangle.c
index 36afcfae278..d6daf23af27 100644
--- a/libiberty/rust-demangle.c
+++ b/libiberty/rust-demangle.c
@@ -1082,6 +1082,18 @@ demangle_path_maybe_open_generics (struct rust_demangler *rdm)
if (rdm->errored)
return open;
+ if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+ {
+ ++ rdm->recursion;
+ if (rdm->recursion > RUST_MAX_RECURSION_COUNT)
+ {
+ /* FIXME: There ought to be a way to report
+ that the recursion limit has been reached. */
+ rdm->errored = 1;
+ goto end_of_func;
+ }
+ }
+
if (eat (rdm, 'B'))
{
backref = parse_integer_62 (rdm);
@@ -1107,6 +1119,11 @@ demangle_path_maybe_open_generics (struct rust_demangler *rdm)
}
else
demangle_path (rdm, 0);
+
+ end_of_func:
+ if (rdm->recursion != RUST_NO_RECURSION_LIMIT)
+ -- rdm->recursion;
+
return open;
}
next reply other threads:[~2022-07-01 15:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-01 15:12 Nick Clifton [this message]
2022-07-01 16:53 ` Jeff Law
2022-07-04 10:08 ` Nick Clifton
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