b46d250656
The kernel version check is used to avoid glibc to run on older kernels where some syscall are not available and fallback code are not enabled to handle graciously fail. However, it does not prevent if the kernel does not correctly advertise its version through vDSO note, uname or procfs. Also kernel version checks are sometime not desirable by users, where they want to deploy on different system with different kernel version knowing the minimum set of syscall is always presented on such systems. The kernel version check has been removed along with the LD_ASSUME_KERNEL environment variable. The minimum kernel used to built glibc is still provided through NT_GNU_ABI_TAG ELF note and also printed when libc.so is issued. Checked on x86_64-linux-gnu.
55 lines
1.8 KiB
C
55 lines
1.8 KiB
C
/* Operating system specific code for generic dynamic loader functions. Linux.
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Copyright (C) 2000-2022 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <dl-sysdep.h>
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#include <endian.h>
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#include <fcntl.h>
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#include <stdint.h>
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#include <not-cancel.h>
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static inline uintptr_t __attribute__ ((always_inline))
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_dl_setup_stack_chk_guard (void *dl_random)
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{
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union
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{
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uintptr_t num;
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unsigned char bytes[sizeof (uintptr_t)];
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} ret;
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/* We need in the moment only 8 bytes on 32-bit platforms and 16
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bytes on 64-bit platforms. Therefore we can use the data
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directly and not use the kernel-provided data to seed a PRNG. */
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memcpy (ret.bytes, dl_random, sizeof (ret));
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#if BYTE_ORDER == LITTLE_ENDIAN
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ret.num &= ~(uintptr_t) 0xff;
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#elif BYTE_ORDER == BIG_ENDIAN
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ret.num &= ~((uintptr_t) 0xff << (8 * (sizeof (ret) - 1)));
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#else
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# error "BYTE_ORDER unknown"
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#endif
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return ret.num;
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}
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static inline uintptr_t __attribute__ ((always_inline))
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_dl_setup_pointer_guard (void *dl_random, uintptr_t stack_chk_guard)
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{
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uintptr_t ret;
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memcpy (&ret, (char *) dl_random + sizeof (ret), sizeof (ret));
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return ret;
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}
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