From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 2178) id 5855C3858C39; Fri, 14 Oct 2022 09:02:47 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5855C3858C39 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1665738167; bh=kbyMOCjL0eLt3rLBx2lSU/Xq8xdICygN7K0kGhINdVo=; h=From:To:Subject:Date:From; b=OnyBXplia2slpBfHNnp+uM3dmagMKnHkbBUBMWJR3bE3sC9ULhcT1zs4ckr4GAhmj MAPVGoZmyX4WgMVyQEQDiE8PZK+ORwgn2M4ZeRnuQtQGRTpWylIRzO7rECbQ+hAUsv SYClwZYpJe+D3VxSB90hD+Drra+mj3dxbYgqhOW0= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Florian Weimer To: glibc-cvs@sourceware.org Subject: [glibc] elf: Do not completely clear reused namespace in dlmopen (bug 29600) X-Act-Checkin: glibc X-Git-Author: Florian Weimer X-Git-Refname: refs/heads/master X-Git-Oldrev: 15a94e6668a6d7c5697e805d8d67f1d102d0d52e X-Git-Newrev: 2c42257314536b94cc8d52edede86e94e98c1436 Message-Id: <20221014090247.5855C3858C39@sourceware.org> Date: Fri, 14 Oct 2022 09:02:47 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=2c42257314536b94cc8d52edede86e94e98c1436 commit 2c42257314536b94cc8d52edede86e94e98c1436 Author: Florian Weimer Date: Fri Oct 14 11:02:25 2022 +0200 elf: Do not completely clear reused namespace in dlmopen (bug 29600) The data in the _ns_debug member must be preserved, otherwise _dl_debug_initialize enters an infinite loop. To be conservative, only clear the libc_map member for now, to fix bug 29528. Fixes commit d0e357ff45a75553dee3b17ed7d303bfa544f6fe ("elf: Call __libc_early_init for reused namespaces (bug 29528)"), by reverting most of it. Reviewed-by: Carlos O'Donell Tested-by: Carlos O'Donell Diff: --- elf/dl-open.c | 14 ++++++-------- elf/tst-dlmopen-twice.c | 28 ++++++++++++++++++++++++---- 2 files changed, 30 insertions(+), 12 deletions(-) diff --git a/elf/dl-open.c b/elf/dl-open.c index 46e8066fd8..e7db5e9642 100644 --- a/elf/dl-open.c +++ b/elf/dl-open.c @@ -844,15 +844,13 @@ _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid, _dl_signal_error (EINVAL, file, NULL, N_("\ no more namespaces available for dlmopen()")); } + else if (nsid == GL(dl_nns)) + { + __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock); + ++GL(dl_nns); + } - if (nsid == GL(dl_nns)) - ++GL(dl_nns); - - /* Initialize the new namespace. Most members are - zero-initialized, only the lock needs special treatment. */ - memset (&GL(dl_ns)[nsid], 0, sizeof (GL(dl_ns)[nsid])); - __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock); - + GL(dl_ns)[nsid].libc_map = NULL; _dl_debug_update (nsid)->r_state = RT_CONSISTENT; } /* Never allow loading a DSO in a namespace which is empty. Such diff --git a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c index 449f3c8fa9..70c71fe19c 100644 --- a/elf/tst-dlmopen-twice.c +++ b/elf/tst-dlmopen-twice.c @@ -16,18 +16,38 @@ License along with the GNU C Library; if not, see . */ -#include +#include #include +#include -static int -do_test (void) +/* Run the test multiple times, to check finding a new namespace while + another namespace is already in use. This used to trigger bug 29600. */ +static void +recurse (int depth) { - void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", RTLD_NOW); + if (depth == 0) + return; + + printf ("info: running at depth %d\n", depth); + void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", + RTLD_NOW); xdlclose (handle); handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod2.so", RTLD_NOW); int (*run_check) (void) = xdlsym (handle, "run_check"); TEST_COMPARE (run_check (), 0); + recurse (depth - 1); xdlclose (handle); +} + +static int +do_test (void) +{ + /* First run the test without nesting. */ + recurse (1); + + /* Then with nesting. The constant needs to be less than the + internal DL_NNS namespace constant. */ + recurse (10); return 0; }