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author | H.J. Lu <hjl.tools@gmail.com> | 2020-07-16 03:37:10 -0700 |
---|---|---|
committer | H.J. Lu <hjl.tools@gmail.com> | 2020-07-27 12:32:41 -0700 |
commit | 0ad926f34937f7b4843a8b49e5d93199601fe324 (patch) | |
tree | ca8a5ee934163ebaff49497afd15513bf6cc8fda /nptl | |
parent | b51c1500e02cec3a61c385d5aa919287f32bbd58 (diff) | |
download | glibc-0ad926f34937f7b4843a8b49e5d93199601fe324.zip glibc-0ad926f34937f7b4843a8b49e5d93199601fe324.tar.gz glibc-0ad926f34937f7b4843a8b49e5d93199601fe324.tar.bz2 |
nptl: Zero-extend arguments to SETXID syscalls [BZ #26248]
nptl has
/* Opcodes and data types for communication with the signal handler to
change user/group IDs. */
struct xid_command
{
int syscall_no;
long int id[3];
volatile int cntr;
volatile int error;
};
/* This must be last, otherwise the current thread might not have
permissions to send SIGSETXID syscall to the other threads. */
result = INTERNAL_SYSCALL_NCS (cmdp->syscall_no, 3,
cmdp->id[0], cmdp->id[1], cmdp->id[2]);
But the second argument of setgroups syscal is a pointer:
int setgroups (size_t size, const gid_t *list);
But on x32, pointers passed to syscall must have pointer type so that
they will be zero-extended. The kernel XID arguments are unsigned and
do not require sign extension. Change xid_command to
struct xid_command
{
int syscall_no;
unsigned long int id[3];
volatile int cntr;
volatile int error;
};
so that all arguments are zero-extended. A testcase is added for x32 and
setgroups returned with EFAULT when running as root without the fix.
Diffstat (limited to 'nptl')
-rw-r--r-- | nptl/Makefile | 2 | ||||
-rw-r--r-- | nptl/descr.h | 8 | ||||
-rw-r--r-- | nptl/tst-setgroups.c | 79 |
3 files changed, 87 insertions, 2 deletions
diff --git a/nptl/Makefile b/nptl/Makefile index 5e62c77..89569c4 100644 --- a/nptl/Makefile +++ b/nptl/Makefile @@ -310,7 +310,7 @@ tests-internal := tst-robustpi8 tst-rwlock19 tst-rwlock20 \ tst-setgetname \ xtests = tst-setuid1 tst-setuid1-static tst-setuid2 \ - tst-mutexpp1 tst-mutexpp6 tst-mutexpp10 + tst-mutexpp1 tst-mutexpp6 tst-mutexpp10 tst-setgroups # This test can run into task limits because of a linux kernel bug # and then cause the make process to fail too, see bug 24537. diff --git a/nptl/descr.h b/nptl/descr.h index 6a509b6..d8343ff 100644 --- a/nptl/descr.h +++ b/nptl/descr.h @@ -95,7 +95,13 @@ struct pthread_unwind_buf struct xid_command { int syscall_no; - long int id[3]; + /* Enforce zero-extension for the pointer argument in + + int setgroups (size_t size, const gid_t *list); + + The kernel XID arguments are unsigned and do not require sign + extension. */ + unsigned long int id[3]; volatile int cntr; volatile int error; /* -1: no call yet, 0: success seen, >0: error seen. */ }; diff --git a/nptl/tst-setgroups.c b/nptl/tst-setgroups.c new file mode 100644 index 0000000..ae3c1b1 --- /dev/null +++ b/nptl/tst-setgroups.c @@ -0,0 +1,79 @@ +/* Test setgroups as root and in the presence of threads (Bug 26248) + Copyright (C) 2020 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 + <https://www.gnu.org/licenses/>. */ + +#include <stdlib.h> +#include <limits.h> +#include <grp.h> +#include <errno.h> +#include <error.h> +#include <support/xthread.h> +#include <support/support.h> +#include <support/test-driver.h> +#include <support/xunistd.h> + +/* The purpose of this test is to test the setgroups API as root and in + the presence of threads. Once we create a thread the setgroups + implementation must ensure that all threads are set to the same + group and this operation should not fail. Lastly we test setgroups + with a zero sized group and a bad address and verify we get EPERM. */ + +static void * +start_routine (void *args) +{ + return NULL; +} + +static int +do_test (void) +{ + int size; + /* NB: Stack address can be at 0xfffXXXXX on 32-bit OSes. */ + gid_t list[NGROUPS_MAX]; + int status = EXIT_SUCCESS; + + pthread_t thread = xpthread_create (NULL, start_routine, NULL); + + size = getgroups (sizeof (list) / sizeof (list[0]), list); + if (size < 0) + { + status = EXIT_FAILURE; + error (0, errno, "getgroups failed"); + } + if (setgroups (size, list) < 0) + { + if (errno == EPERM) + status = EXIT_UNSUPPORTED; + else + { + status = EXIT_FAILURE; + error (0, errno, "setgroups failed"); + } + } + + if (status == EXIT_SUCCESS && setgroups (0, list) < 0) + { + status = EXIT_FAILURE; + error (0, errno, "setgroups failed"); + } + + xpthread_join (thread); + + return status; +} + +#include <support/test-driver.c> |