From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id D263D3846056; Sat, 21 May 2022 17:23:54 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D263D3846056 From: "r3tr0spect2019 at gmail dot com" To: gdb-prs@sourceware.org Subject: [Bug c++/29166] New: `demangle_const` causes infinite recursion and stack overflow Date: Sat, 21 May 2022 17:23:54 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: new X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gdb X-Bugzilla-Component: c++ X-Bugzilla-Version: HEAD X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: r3tr0spect2019 at gmail dot com X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: unassigned at sourceware dot org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone Message-ID: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://sourceware.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-BeenThere: gdb-prs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gdb-prs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 May 2022 17:23:54 -0000 https://sourceware.org/bugzilla/show_bug.cgi?id=3D29166 Bug ID: 29166 Summary: `demangle_const` causes infinite recursion and stack overflow Product: gdb Version: HEAD Status: UNCONFIRMED Severity: normal Priority: P2 Component: c++ Assignee: unassigned at sourceware dot org Reporter: r3tr0spect2019 at gmail dot com Target Milestone: --- Original Post: `https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D105115` The bug is similar to CVE-2021-3530, which was reported here: `https://bugs.launchpad.net/ubuntu/+source/binutils/+bug/1925348`. Commit: `e84412c6a3c3eed1a4eca5fe18f329bfa7efea40` at `https://github.com/bminor/binutils-gdb`. The simplified PoC: $ echo _RYAbB2_ | ./binutils/cxxfilt Segmentation fault Root Cause Analysis: 1. In `rust_demangle_callback`, "_R" at beginning causes `rdm.version =3D=3D 0`[1][2], so `demangle_path` in the else-branch is called[3] with `rdm.sym = =3D=3D "YAbB2_"`, with `rdm.next` field initialized to 0. 2. Next char 'Y' causes `demangle_type` to be called[4] in a switch-case branch, with `rdm.next =3D=3D 1`. 3. Next char 'A' causes `demangle_type` to be called first[5] to consume ch= ar 'b', then `demangle_const` is called[6] with `rdm.next =3D=3D 3`. 4. Next char 'B' is consumed[7], and "2_" is parsed as `integer_62`[8] to be value 3, and this vlaue is assigned to `rdm.next`, then `demangle_const` is called recursively[9]. However, currently the situation is `rdm.next =3D=3D= 3` again, which is exactly same as last call to `demangle_const`, and this cau= ses infinite recursion. [1] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1356 [2] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1362 [3] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1453 [4] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L759 [5] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L934 [6] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L938 [7] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1151 [8] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1153 [9] 626d0e40e55c35a4f143b70def498734e8ed3c2a/libiberty/rust-demangle.c#L1158 Possible Fix: The infinite recursion check added in this [commit](https://github.com/bminor/binutils-gdb/commit/f10f8617a302f45dae72= 1eae0cd659911f03d864) should also be applied to `demangle_const` --=20 You are receiving this mail because: You are on the CC list for the bug.=