From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7814) id 6E190382893D; Fri, 27 May 2022 19:34:51 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 6E190382893D Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Fangrui Song To: glibc-cvs@sourceware.org Subject: [glibc] dlsym: Make RTLD_NEXT prefer default version definition [BZ #14932] X-Act-Checkin: glibc X-Git-Author: Fangrui Song X-Git-Refname: refs/heads/master X-Git-Oldrev: f8587a61892cbafd98ce599131bf4f103466f084 X-Git-Newrev: efa7936e4c91b1c260d03614bb26858fbb8a0204 Message-Id: <20220527193451.6E190382893D@sourceware.org> Date: Fri, 27 May 2022 19:34:51 +0000 (GMT) X-BeenThere: glibc-cvs@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Glibc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 May 2022 19:34:51 -0000 https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=efa7936e4c91b1c260d03614bb26858fbb8a0204 commit efa7936e4c91b1c260d03614bb26858fbb8a0204 Author: Fangrui Song Date: Fri May 27 12:34:49 2022 -0700 dlsym: Make RTLD_NEXT prefer default version definition [BZ #14932] When the first object providing foo defines both foo@v1 and foo@@v2, dlsym(RTLD_NEXT, "foo") returns foo@v1 while dlsym(RTLD_DEFAULT, "foo") returns foo@@v2. The issue is that RTLD_DEFAULT uses the DL_LOOKUP_RETURN_NEWEST flag while RTLD_NEXT doesn't. Fix the RTLD_NEXT branch to use DL_LOOKUP_RETURN_NEWEST. Note: the new behavior matches FreeBSD rtld. Future sanitizers will not need to add versioned interceptors like https://reviews.llvm.org/D96348 Reviewed-by: Adhemerval Zanella Diff: --- elf/Makefile | 7 +++++++ elf/dl-sym.c | 2 +- elf/nextmod3.c | 20 ++++++++++++++++++++ elf/nextmod3.map | 3 +++ elf/tst-next-ver.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 77 insertions(+), 1 deletion(-) diff --git a/elf/Makefile b/elf/Makefile index 838fe39afb..bfc9179fc5 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -426,6 +426,7 @@ tests += \ tst-initorder2 \ tst-latepthread \ tst-main1 \ + tst-next-ver \ tst-nodelete2 \ tst-nodelete-dlclose \ tst-nodelete-opened \ @@ -712,6 +713,7 @@ modules-names += \ neededobj6 \ nextmod1 \ nextmod2 \ + nextmod3 \ nodel2mod1 \ nodel2mod2 \ nodel2mod3 \ @@ -1690,6 +1692,9 @@ $(objpfx)reldep4.out: $(objpfx)reldep4mod1.so $(objpfx)reldep4mod2.so $(objpfx)next: $(objpfx)nextmod1.so $(objpfx)nextmod2.so LDFLAGS-next = -Wl,--no-as-needed +$(objpfx)tst-next-ver: $(objpfx)nextmod3.so +LDFLAGS-tst-next-ver = -Wl,--no-as-needed + $(objpfx)unload2.out: $(objpfx)unload2mod.so $(objpfx)unload2dep.so $(objpfx)lateglobal.out: $(objpfx)ltglobmod1.so $(objpfx)ltglobmod2.so @@ -2437,6 +2442,8 @@ $(objpfx)tst-linkall-static: \ endif endif +LDFLAGS-nextmod3.so = -Wl,--version-script=nextmod3.map + # The application depends on the DSO, and the DSO loads the plugin. # The plugin also depends on the DSO. This creates the circular # dependency via dlopen that we're testing to make sure works. diff --git a/elf/dl-sym.c b/elf/dl-sym.c index aa993942df..b1cf42f36d 100644 --- a/elf/dl-sym.c +++ b/elf/dl-sym.c @@ -144,7 +144,7 @@ RTLD_NEXT used in code not dynamically loaded")); l = l->l_loader; result = GLRO(dl_lookup_symbol_x) (name, match, &ref, l->l_local_scope, - vers, 0, 0, match); + vers, 0, flags, match); } else { diff --git a/elf/nextmod3.c b/elf/nextmod3.c new file mode 100644 index 0000000000..cd7bdb36af --- /dev/null +++ b/elf/nextmod3.c @@ -0,0 +1,20 @@ +int +foo_v1 (int a) +{ + return 1; +} +asm (".symver foo_v1, foo@v1"); + +int +foo_v2 (int a) +{ + return 2; +} +asm (".symver foo_v2, foo@v2"); + +int +foo (int a) +{ + return 3; +} +asm (".symver foo, foo@@@v3"); diff --git a/elf/nextmod3.map b/elf/nextmod3.map new file mode 100644 index 0000000000..eb0e7d7800 --- /dev/null +++ b/elf/nextmod3.map @@ -0,0 +1,3 @@ +v1 { }; +v2 { } v1; +v3 { foo; } v2; diff --git a/elf/tst-next-ver.c b/elf/tst-next-ver.c new file mode 100644 index 0000000000..7241f9038b --- /dev/null +++ b/elf/tst-next-ver.c @@ -0,0 +1,46 @@ +/* Test RTLD_DEFAULT/RTLD_NEXT when the definition has multiple versions. + Copyright (C) 2018-2022 Free Software Foundation, Inc. + 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 + . */ + +#include +#include + +#include "testobj.h" + +static int +do_test (void) +{ + /* Resolve to foo@@v3 in nextmod3.so, instead of + foo@v1 or foo@v2. */ + int (*fp) (int) = dlsym (RTLD_DEFAULT, "foo"); + int res = fp (0); + printf ("preload (0) = %d, %s\n", res, res == 3 ? "ok" : "wrong"); + if (res != 3) + return 1; + + /* Resolve to foo@@v3 in nextmod3.so, instead of + foo@v1 or foo@v2. */ + fp = dlsym (RTLD_NEXT, "foo"); + res = fp (0); + printf ("preload (0) = %d, %s\n", res, res == 3 ? "ok" : "wrong"); + if (res != 3) + return 1; + + return 0; +} + +#include