From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 7932) id 9B6A83858D37; Tue, 16 Apr 2024 20:33:54 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9B6A83858D37 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1713299634; bh=2unGihPvazRZ8+8xmzlKBSdOwy7AwVz7KxusS/JVMag=; h=From:To:Subject:Date:From; b=Cjd3rIDQNKVWmSyEwwMouluAS0vY0g9RXdOJf2OlJBITCnIkLfjYB04cRcMCYZ3uC kb5VAIZ8nqdjcvC6aeHFlvR80V44zawc8qkAeS2bM70ptTB2en6tHAlgn6GhjdPGvt 2dHhWhYaDYp7iXihJg1V1zK3JV+NOp43FGQqB1bk= Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Joe Simmons-Talbott To: glibc-cvs@sourceware.org Subject: [glibc] elf/rtld: Count skipped environment variables for enable_secure X-Act-Checkin: glibc X-Git-Author: Joe Simmons-Talbott X-Git-Refname: refs/heads/master X-Git-Oldrev: 14e56bd4ce15ac2d1cc43f762eb2e6b83fec1afe X-Git-Newrev: 59974938fe1f4add843f5325f78e2a7ccd8db853 Message-Id: <20240416203354.9B6A83858D37@sourceware.org> Date: Tue, 16 Apr 2024 20:33:54 +0000 (GMT) List-Id: https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=59974938fe1f4add843f5325f78e2a7ccd8db853 commit 59974938fe1f4add843f5325f78e2a7ccd8db853 Author: Joe Simmons-Talbott Date: Tue Apr 16 20:31:42 2024 +0000 elf/rtld: Count skipped environment variables for enable_secure When using the glibc.rtld.enable_secure tunable we need to keep track of the count of environment variables we skip due to __libc_enable_secure being set and adjust the auxv section of the stack. This fixes an assertion when running ld.so directly with glibc.rtld.enable_secure set. Add a testcase that ensures the assert is not hit. elf/rtld.c:1324 assert (auxv == sp + 1); Reviewed-by: Adhemerval Zanella Diff: --- elf/Makefile | 10 ++++++++++ elf/rtld.c | 31 +++++++++++++++++++++++-------- elf/tst-tunables-enable_secure-env.c | 33 +++++++++++++++++++++++++++++++++ 3 files changed, 66 insertions(+), 8 deletions(-) diff --git a/elf/Makefile b/elf/Makefile index fb3c3c4dff..ec1516ca3d 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -315,6 +315,7 @@ tests := \ tst-leaks1 \ tst-stringtable \ tst-tls9 \ + tst-tunables-enable_secure-env \ # tests tests-internal := \ @@ -1188,6 +1189,7 @@ tests-special += \ $(objpfx)tst-trace3.out \ $(objpfx)tst-trace4.out \ $(objpfx)tst-trace5.out \ + $(objpfx)tst-tunables-enable_secure-env.out \ $(objpfx)tst-unused-dep-cmp.out \ $(objpfx)tst-unused-dep.out \ # tests-special @@ -2215,6 +2217,14 @@ $(objpfx)tst-unused-dep-cmp.out: $(objpfx)tst-unused-dep.out cmp $< /dev/null > $@; \ $(evaluate-test) +$(objpfx)tst-tunables-enable_secure-env.out: $(objpfx)tst-tunables-enable_secure-env + $(test-wrapper-env) \ + GLIBC_TUNABLES=glibc.rtld.enable_secure=1 \ + $(rtld-prefix) \ + $< > $@; \ + $(evaluate-test) + + $(objpfx)tst-audit11.out: $(objpfx)tst-auditmod11.so $(objpfx)tst-audit11mod1.so tst-audit11-ENV = LD_AUDIT=$(objpfx)tst-auditmod11.so $(objpfx)tst-audit11mod1.so: $(objpfx)tst-audit11mod2.so diff --git a/elf/rtld.c b/elf/rtld.c index 18d73f19c6..d116a436f5 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -155,7 +155,7 @@ static void dl_main_state_init (struct dl_main_state *state); Since all of them start with `LD_' we are a bit smarter while finding all the entries. */ extern char **_environ attribute_hidden; -static void process_envvars (struct dl_main_state *state); +static int process_envvars (struct dl_main_state *state); int _dl_argc attribute_relro attribute_hidden; char **_dl_argv attribute_relro = NULL; @@ -1289,7 +1289,7 @@ rtld_setup_main_map (struct link_map *main_map) _dl_argv and _dl_argc accordingly. Those arguments are removed from argv here. */ static void -_dl_start_args_adjust (int skip_args) +_dl_start_args_adjust (int skip_args, int skip_env) { void **sp = (void **) (_dl_argv - skip_args - 1); void **p = sp + skip_args; @@ -1321,7 +1321,7 @@ _dl_start_args_adjust (int skip_args) while (*p != NULL); #ifdef HAVE_AUX_VECTOR - void **auxv = (void **) GLRO(dl_auxv) - skip_args; + void **auxv = (void **) GLRO(dl_auxv) - skip_args - skip_env; GLRO(dl_auxv) = (ElfW(auxv_t) *) auxv; /* Aliasing violation. */ assert (auxv == sp + 1); @@ -1352,6 +1352,7 @@ dl_main (const ElfW(Phdr) *phdr, unsigned int i; bool rtld_is_main = false; void *tcbp = NULL; + int skip_env = 0; struct dl_main_state state; dl_main_state_init (&state); @@ -1365,7 +1366,7 @@ dl_main (const ElfW(Phdr) *phdr, #endif /* Process the environment variable which control the behaviour. */ - process_envvars (&state); + skip_env = process_envvars (&state); #ifndef HAVE_INLINED_SYSCALLS /* Set up a flag which tells we are just starting. */ @@ -1630,7 +1631,7 @@ dl_main (const ElfW(Phdr) *phdr, _dl_argv[0] = argv0; /* Adjust arguments for the application entry point. */ - _dl_start_args_adjust (_dl_argv - orig_argv); + _dl_start_args_adjust (_dl_argv - orig_argv, skip_env); } else { @@ -2534,11 +2535,12 @@ a filename can be specified using the LD_DEBUG_OUTPUT environment variable.\n"); } } -static void +static int process_envvars_secure (struct dl_main_state *state) { char **runp = _environ; char *envline; + int skip_env = 0; while ((envline = _dl_next_ld_env_entry (&runp)) != NULL) { @@ -2580,6 +2582,14 @@ process_envvars_secure (struct dl_main_state *state) const char *nextp = UNSECURE_ENVVARS; do { + /* Keep track of the number of environment variables that were set in + the environment and are unset below. Use getenv() which returns + non-NULL if the variable is set in the environment. This count is + needed if we need to adjust the location of the AUX vector on the + stack when running ld.so directly. */ + if (getenv (nextp) != NULL) + skip_env++; + unsetenv (nextp); nextp = strchr (nextp, '\0') + 1; } @@ -2592,6 +2602,8 @@ process_envvars_secure (struct dl_main_state *state) || state->mode != rtld_mode_normal || state->version_info) _exit (5); + + return skip_env; } static void @@ -2745,13 +2757,16 @@ process_envvars_default (struct dl_main_state *state) } } -static void +static int process_envvars (struct dl_main_state *state) { + int skip_env = 0; if (__glibc_unlikely (__libc_enable_secure)) - process_envvars_secure (state); + skip_env += process_envvars_secure (state); else process_envvars_default (state); + + return skip_env; } #if HP_TIMING_INLINE diff --git a/elf/tst-tunables-enable_secure-env.c b/elf/tst-tunables-enable_secure-env.c new file mode 100644 index 0000000000..24e846f299 --- /dev/null +++ b/elf/tst-tunables-enable_secure-env.c @@ -0,0 +1,33 @@ +/* Check enable_secure tunable handles removed ENV variables without + assertions. + Copyright (C) 2024 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 + +static int +do_test (int argc, char *argv[]) +{ + /* Ensure that no assertions are hit when a dynamically linked application + runs. This test requires that GLIBC_TUNABLES=glibc.rtld.enable_secure=1 + is set. */ + return 0; +} + +#define TEST_FUNCTION_ARGV do_test +#include