From patchwork Fri Mar 4 17:12:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Adhemerval Zanella X-Patchwork-Id: 51584 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 84F393857C53 for ; Fri, 4 Mar 2022 17:12:36 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 84F393857C53 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1646413956; bh=pmQ2EW8y9ionOjfaTI0lAsLqKcSiHuwoYEg3r1+pQ94=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=ZQSB77cCycomim7Fv4P4gFOrTClGnHLAy1qGxTjmL7o7sWZHvZZsUUYARDA2cJ2Aj b8kDfAsA6ammx1qZpDG4CRjKp3ARr/TtQ/RngjeYkQxd9m1VQPP5aDIN5QLwLLeQft 8ySTI+TC9f3EnTAWzqlnRJsFAGtrep9rr5wbinaQ= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from mail-oo1-xc2d.google.com (mail-oo1-xc2d.google.com [IPv6:2607:f8b0:4864:20::c2d]) by sourceware.org (Postfix) with ESMTPS id C40C43858D39 for ; Fri, 4 Mar 2022 17:12:12 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org C40C43858D39 Received: by mail-oo1-xc2d.google.com with SMTP id 6-20020a4a0906000000b0031d7eb98d31so10094191ooa.10 for ; Fri, 04 Mar 2022 09:12:12 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=pmQ2EW8y9ionOjfaTI0lAsLqKcSiHuwoYEg3r1+pQ94=; b=6TsEeS3dSu3+9NvqpmCGMUP9I2f2UcC7b5GjM+haNPrMTaEiSGi0pP8UNfjJ+34GMr k6oTgpSe9TbtTnyhXYvVBzAbVBuBr5eekzCFixz6eUpBiJLAGr+72iNcq0Cx3c8l9PMl NwqgsKCrOGJhf9ON1O6IpbI5UKMZVA7rs3dsqqW2RgRklafa7Jc+I8myHQQkYnwissBn NKFaZwzgcQZJIPG7Y2TOEiyzavZ9MLvPl/Xk8180OWTzGjQLOPldOPQss1yzY6Pai85a Kbt0vGsHqkV7DU3RVvPdNYl/TuawflSPSmHCm2cNT/joXwdjTgB9jeQ1AeVdN05Ikt2H pNnA== X-Gm-Message-State: AOAM530X0k1pCjKvzfkXdUvrdxLTPYsXF3W/DehSVB8Abu2/WYpfKgXr DiUYGdhQW/l083ODUv7hKPyfIQ7/F/I/pA== X-Google-Smtp-Source: ABdhPJyS3jKtIcDjN/zqvmk+XITpiyN1iFE9ZIWaddbeHeZof3YA8IHNzo3a5NvsP/r3DxsZHv7sfA== X-Received: by 2002:a05:6870:b303:b0:d6:f4d1:990d with SMTP id a3-20020a056870b30300b000d6f4d1990dmr108345oao.53.1646413931622; Fri, 04 Mar 2022 09:12:11 -0800 (PST) Received: from birita.. ([2804:431:c7ca:2dcb:a992:742c:8048:43bc]) by smtp.gmail.com with ESMTPSA id k25-20020a9d7019000000b005af14095afdsm2556834otj.0.2022.03.04.09.12.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Mar 2022 09:12:10 -0800 (PST) To: libc-alpha@sourceware.org, Florian Weimer Subject: [PATCH v5] elf: Fix DFS sorting algorithm for LD_TRACE_LOADED_OBJECTS with missing libraries (BZ #28868) Date: Fri, 4 Mar 2022 14:12:00 -0300 Message-Id: <20220304171200.3101821-1-adhemerval.zanella@linaro.org> X-Mailer: git-send-email 2.32.0 MIME-Version: 1.0 X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP, T_SCC_BODY_TEXT_LINE autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Adhemerval Zanella via Libc-alpha From: Adhemerval Zanella Reply-To: Adhemerval Zanella Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" The _dl_map_object_deps ignores l_faked objects (set if the underlying file can't be opened by _dl_map_object): 490 for (nlist = 0, runp = known; runp; runp = runp->next) 491 { 492 if (__builtin_expect (trace_mode, 0) && runp->map->l_faked) 493 /* This can happen when we trace the loading. */ 494 --map->l_searchlist.r_nlist; 495 else 496 { 497 if (runp->map == map) 498 map_index = nlist; 499 map->l_searchlist.r_list[nlist++] = runp->map; 500 } 501 502 /* Now clear all the mark bits we set in the objects on the search list 503 to avoid duplicates, so the next call starts fresh. */ 504 runp->map->l_reserved = 0; 505 } If there any missing libraries being processed, they will not be considered on final nlist size passed on _dl_sort_maps later in the function. And it is then used on _dl_sort_maps_dfs on the stack allocated working maps: 222 /* Array to hold RPO sorting results, before we copy back to maps[]. */ 223 struct link_map *rpo[nmaps]; 224 225 /* The 'head' position during each DFS iteration. Note that we start at 226 one past the last element due to first-decrement-then-store (see the 227 bottom of above dfs_traversal() routine). */ 228 struct link_map **rpo_head = &rpo[nmaps]; However while transversing the 'l_initfini' on dfs_traversal it will still considere the l_faked maps and thus update rpo more times than the allocated working 'rpo', overflowing the stack object. As suggested in bugzilla, one option would be to avoid sorting the maps for trace mode. However I think ignoring l_faked object does make sense (there is one less constraint to call the sorting function), it allows a slight less stack usage for trace, and it is slight simpler solution. The tests does trigger the stack overflow, however I tried to make it more generic to check different scenarios or missing objects. Checked on x86_64-linux-gnu. --- v5: Refactor tests make rules. v4: Use --soname to build the libraries, fixed typos. v3: Removed stamp files to avoid add them as linker depedencies and moved test evaluation to python script. v2: Added comments and fixed the default tst-trace1 --library-path. --- elf/Makefile | 54 ++++++++++++++++++++ elf/dl-deps.c | 2 + elf/dl-sort-maps.c | 4 +- elf/libtracemod1-1.c | 1 + elf/libtracemod2-1.c | 1 + elf/libtracemod3-1.c | 1 + elf/libtracemod4-1.c | 1 + elf/libtracemod5-1.c | 1 + elf/libtracemod6.c | 1 + elf/tst-trace1.exp | 4 ++ elf/tst-trace2.exp | 6 +++ elf/tst-trace3.exp | 6 +++ elf/tst-trace4.exp | 6 +++ elf/tst-trace5.exp | 6 +++ scripts/tst-ld-trace.py | 108 ++++++++++++++++++++++++++++++++++++++++ 15 files changed, 201 insertions(+), 1 deletion(-) create mode 100644 elf/libtracemod1-1.c create mode 100644 elf/libtracemod2-1.c create mode 100644 elf/libtracemod3-1.c create mode 100644 elf/libtracemod4-1.c create mode 100644 elf/libtracemod5-1.c create mode 100644 elf/libtracemod6.c create mode 100644 elf/tst-trace1.exp create mode 100644 elf/tst-trace2.exp create mode 100644 elf/tst-trace3.exp create mode 100644 elf/tst-trace4.exp create mode 100644 elf/tst-trace5.exp create mode 100755 scripts/tst-ld-trace.py diff --git a/elf/Makefile b/elf/Makefile index c96924e9c2..f30f64991f 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -617,6 +617,11 @@ modules-names = \ libmarkermod4-2 \ libmarkermod4-3 \ libmarkermod4-4 \ + libtracemod1-1 \ + libtracemod2-1 \ + libtracemod3-1 \ + libtracemod4-1 \ + libtracemod5-1 \ ltglobmod1 \ ltglobmod2 \ neededobj1 \ @@ -1079,6 +1084,11 @@ tests-special += \ $(objpfx)tst-initorder2-cmp.out \ $(objpfx)tst-unused-dep-cmp.out \ $(objpfx)tst-unused-dep.out \ + $(objpfx)tst-trace1.out \ + $(objpfx)tst-trace2.out \ + $(objpfx)tst-trace3.out \ + $(objpfx)tst-trace4.out \ + $(objpfx)tst-trace5.out \ # tests-special endif @@ -2725,3 +2735,47 @@ $(objpfx)tst-p_align3: $(objpfx)tst-p_alignmod3.so $(objpfx)tst-p_align3.out: tst-p_align3.sh $(objpfx)tst-p_align3 $(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \ $(evaluate-test) + +LDFLAGS-libtracemod1-1.so += -Wl,-soname,libtracemod1.so +LDFLAGS-libtracemod2-1.so += -Wl,-soname,libtracemod2.so +LDFLAGS-libtracemod3-1.so += -Wl,-soname,libtracemod3.so +LDFLAGS-libtracemod4-1.so += -Wl,-soname,libtracemod4.so +LDFLAGS-libtracemod5-1.so += -Wl,-soname,libtracemod5.so + +$(objpfx)libtracemod1-1.so: $(objpfx)libtracemod2-1.so \ + $(objpfx)libtracemod3-1.so +$(objpfx)libtracemod2-1.so: $(objpfx)libtracemod4-1.so \ + $(objpfx)libtracemod5-1.so + +define libtracemod-x +$(objpfx)libtracemod$(1)/libtracemod$(1).so: $(objpfx)libtracemod$(1)-1.so + $$(make-target-directory) + cp $$< $$@ +endef +libtracemod-suffixes = 1 2 3 4 5 +$(foreach i,$(libtracemod-suffixes), $(eval $(call libtracemod-x,$(i)))) + +define tst-trace-skeleton +$(objpfx)tst-trace$(1).out: $(objpfx)libtracemod1/libtracemod1.so \ + $(objpfx)libtracemod2/libtracemod2.so \ + $(objpfx)libtracemod3/libtracemod3.so \ + $(objpfx)libtracemod4/libtracemod4.so \ + $(objpfx)libtracemod5/libtracemod5.so \ + $(..)scripts/tst-ld-trace.py \ + tst-trace$(1).exp + ( $(PYTHON) $(..)scripts/tst-ld-trace.py \ + "$(test-wrapper-env) $(elf-objpfx)$(rtld-installed-name) \ + --library-path $(common-objpfx):$(strip $(2)) \ + $(objpfx)libtracemod1/libtracemod1.so" tst-trace$(1).exp \ + ) > $$@; $$(evaluate-test) +endef + +$(eval $(call tst-trace-skeleton,1,)) +$(eval $(call tst-trace-skeleton,2,\ + $(objpfx)libtracemod2)) +$(eval $(call tst-trace-skeleton,3,\ + $(objpfx)libtracemod2:$(objpfx)libtracemod3)) +$(eval $(call tst-trace-skeleton,4,\ + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4)) +$(eval $(call tst-trace-skeleton,5,\ + $(objpfx)libtracemod2:$(objpfx)libtracemod3:$(objpfx)libtracemod4:$(objpfx)libtracemod5)) diff --git a/elf/dl-deps.c b/elf/dl-deps.c index a2fc278256..77ff2b3895 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -473,6 +473,8 @@ _dl_map_object_deps (struct link_map *map, for (nlist = 0, runp = known; runp; runp = runp->next) { + /* _dl_sort_maps ignores l_faked object, so it is safe to not considere + them for nlist. */ if (__builtin_expect (trace_mode, 0) && runp->map->l_faked) /* This can happen when we trace the loading. */ --map->l_searchlist.r_nlist; diff --git a/elf/dl-sort-maps.c b/elf/dl-sort-maps.c index 9e9d53ec47..96638d7ed1 100644 --- a/elf/dl-sort-maps.c +++ b/elf/dl-sort-maps.c @@ -140,7 +140,9 @@ static void dfs_traversal (struct link_map ***rpo, struct link_map *map, bool *do_reldeps) { - if (map->l_visited) + /* _dl_map_object_deps ignores l_faked objects when calculating the + number of maps before calling _dl_sort_maps, ignore them as well. */ + if (map->l_visited || map->l_faked) return; map->l_visited = 1; diff --git a/elf/libtracemod1-1.c b/elf/libtracemod1-1.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod1-1.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/libtracemod2-1.c b/elf/libtracemod2-1.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod2-1.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/libtracemod3-1.c b/elf/libtracemod3-1.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod3-1.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/libtracemod4-1.c b/elf/libtracemod4-1.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod4-1.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/libtracemod5-1.c b/elf/libtracemod5-1.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod5-1.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/libtracemod6.c b/elf/libtracemod6.c new file mode 100644 index 0000000000..7c89c9a5a4 --- /dev/null +++ b/elf/libtracemod6.c @@ -0,0 +1 @@ +/* Empty */ diff --git a/elf/tst-trace1.exp b/elf/tst-trace1.exp new file mode 100644 index 0000000000..4a6f5211a6 --- /dev/null +++ b/elf/tst-trace1.exp @@ -0,0 +1,4 @@ +ld 1 +libc 1 +libtracemod2.so 0 +libtracemod3.so 0 diff --git a/elf/tst-trace2.exp b/elf/tst-trace2.exp new file mode 100644 index 0000000000..e13506e2eb --- /dev/null +++ b/elf/tst-trace2.exp @@ -0,0 +1,6 @@ +ld 1 +libc 1 +libtracemod2.so 1 +libtracemod3.so 0 +libtracemod4.so 0 +libtracemod5.so 0 diff --git a/elf/tst-trace3.exp b/elf/tst-trace3.exp new file mode 100644 index 0000000000..e574549d12 --- /dev/null +++ b/elf/tst-trace3.exp @@ -0,0 +1,6 @@ +ld 1 +libc 1 +libtracemod2.so 1 +libtracemod3.so 1 +libtracemod4.so 0 +libtracemod5.so 0 diff --git a/elf/tst-trace4.exp b/elf/tst-trace4.exp new file mode 100644 index 0000000000..31ca97b35b --- /dev/null +++ b/elf/tst-trace4.exp @@ -0,0 +1,6 @@ +ld 1 +libc 1 +libtracemod2.so 1 +libtracemod3.so 1 +libtracemod4.so 1 +libtracemod5.so 0 diff --git a/elf/tst-trace5.exp b/elf/tst-trace5.exp new file mode 100644 index 0000000000..5d7d953726 --- /dev/null +++ b/elf/tst-trace5.exp @@ -0,0 +1,6 @@ +ld 1 +libc 1 +libtracemod2.so 1 +libtracemod3.so 1 +libtracemod4.so 1 +libtracemod5.so 1 diff --git a/scripts/tst-ld-trace.py b/scripts/tst-ld-trace.py new file mode 100755 index 0000000000..f5a4028003 --- /dev/null +++ b/scripts/tst-ld-trace.py @@ -0,0 +1,108 @@ +#!/usr/bin/python3 +# Dump the output of LD_TRACE_LOADED_OBJECTS in architecture neutral format. +# Copyright (C) 2022 Free Software Foundation, Inc. +# Copyright The GNU Toolchain Authors. +# This file is part of the GNU C Library. +# +# The GNU C Library is free software; you can redistribute it and/or +# modify it under the terms of the GNU Lesser General Public +# License as published by the Free Software Foundation; either +# version 2.1 of the License, or (at your option) any later version. +# +# The GNU C Library is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +# Lesser General Public License for more details. +# +# You should have received a copy of the GNU Lesser General Public +# License along with the GNU C Library; if not, see +# . + +import argparse +import os +import subprocess +import sys + +try: + subprocess.run +except: + class _CompletedProcess: + def __init__(self, args, returncode, stdout=None, stderr=None): + self.args = args + self.returncode = returncode + self.stdout = stdout + self.stderr = stderr + + def _run(*popenargs, input=None, timeout=None, check=False, **kwargs): + assert(timeout is None) + with subprocess.Popen(*popenargs, **kwargs) as process: + try: + stdout, stderr = process.communicate(input) + except: + process.kill() + process.wait() + raise + returncode = process.poll() + if check and returncode: + raise subprocess.CalledProcessError(returncode, popenargs) + return _CompletedProcess(popenargs, returncode, stdout, stderr) + + subprocess.run = _run + +def is_vdso(lib): + return lib.startswith('linux-gate') or lib.startswith('linux-vdso') + + +def parse_trace(cmd, fref): + new_env = os.environ.copy() + new_env['LD_TRACE_LOADED_OBJECTS'] = '1' + trace_out = subprocess.run(cmd, stdout=subprocess.PIPE, check=True, + universal_newlines=True, env=new_env).stdout + trace = [] + for line in trace_out.splitlines(): + line = line.strip() + if is_vdso(line): + continue + fields = line.split('=>' if '=>' in line else ' ') + lib = os.path.basename(fields[0].strip()) + if lib.startswith('ld'): + lib = 'ld' + elif lib.startswith('libc'): + lib = 'libc' + found = 1 if fields[1].strip() != 'not found' else 0 + trace += ['{} {}'.format(lib, found)] + trace = sorted(trace) + + reference = sorted(line.replace('\n','') for line in fref.readlines()) + + ret = 0 if trace == reference else 1 + if ret != 0: + for i in reference: + if i not in trace: + print("Only in {}: {}".format(fref.name, i)) + for i in trace: + if i not in reference: + print("Only in trace: {}".format(i)) + + sys.exit(ret) + + +def get_parser(): + parser = argparse.ArgumentParser(description=__doc__) + parser.add_argument('command', + help='comand to run') + parser.add_argument('reference', + help='reference file to compare') + return parser + + +def main(argv): + parser = get_parser() + opts = parser.parse_args(argv) + with open(opts.reference, 'r') as fref: + # Remove the initial 'env' command. + parse_trace(opts.command.split()[1:], fref) + + +if __name__ == '__main__': + main(sys.argv[1:])