New string function explicit_bzero (from OpenBSD).

explicit_bzero(s, n) is the same as memset(s, 0, n), except that the
compiler is not allowed to delete a call to explicit_bzero even if the
memory pointed to by 's' is dead after the call.  Right now, this effect
is achieved externally by having explicit_bzero be a function whose
semantics are unknown to the compiler, and internally, with a no-op
asm statement that clobbers memory.  This does mean that small
explicit_bzero operations cannot be expanded inline as small memset
operations can, but on the other hand, small memset operations do get
deleted by the compiler.  Hopefully full compiler support for
explicit_bzero will happen relatively soon.

There are two new tests: test-explicit_bzero.c verifies the
visible semantics in the same way as the existing test-bzero.c,
and tst-xbzero-opt.c verifies the not-being-optimized-out property.
The latter is conceptually based on a test written by Matthew Dempsky
for the OpenBSD regression suite.

The crypt() implementation has an immediate use for this new feature.
We avoid having to add a GLIBC_PRIVATE alias for explicit_bzero
by running all of libcrypt's calls through the fortified variant,
__explicit_bzero_chk, which is in the impl namespace anyway.  Currently
I'm not aware of anything in libc proper that needs this, but the
glue is all in place if it does become necessary.  The legacy DES
implementation wasn't bothering to clear its buffers, so I added that,
mostly for consistency's sake.

	* string/explicit_bzero.c: New routine.
	* string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests.
	* string/Makefile (routines, strop-tests, tests): Add them.
	* string/test-memset.c: Add ifdeffage for testing explicit_bzero.
	* string/string.h [__USE_MISC]: Declare explicit_bzero.

	* debug/explicit_bzero_chk.c: New routine.
	* debug/Makefile (routines): Add it.
	* debug/tst-chk1.c: Test fortification of explicit_bzero.
	* string/bits/string3.h: Fortify explicit_bzero.

	* manual/string.texi: Document explicit_bzero.
	* NEWS: Mention addition of explicit_bzero.

	* crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate
	data before returning, using explicit_bzero.
	* crypt/md5-crypt.c (__md5_crypt_r): Likewise.
	* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
	* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.

	* include/string.h: Redirect internal uses of explicit_bzero
	to __explicit_bzero_chk[_internal].
	* string/Versions [GLIBC_2.25]: Add explicit_bzero.
	* debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk.
	* sysdeps/arm/nacl/libc.abilist
	* sysdeps/unix/sysv/linux/aarch64/libc.abilist
	* sysdeps/unix/sysv/linux/alpha/libc.abilist
	* sysdeps/unix/sysv/linux/arm/libc.abilist
	* sysdeps/unix/sysv/linux/hppa/libc.abilist
	* sysdeps/unix/sysv/linux/i386/libc.abilist
	* sysdeps/unix/sysv/linux/ia64/libc.abilist
	* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
	* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
	* sysdeps/unix/sysv/linux/microblaze/libc.abilist
	* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
	* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
	* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
	* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
	* sysdeps/unix/sysv/linux/nios2/libc.abilist
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
	* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
	* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
	* sysdeps/unix/sysv/linux/sh/libc.abilist
	* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
	* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
	* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
	* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
	* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist:
	Add entries for explicit_bzero and __explicit_bzero_chk.
This commit is contained in:
Zack Weinberg 2016-09-15 07:29:44 -04:00
parent c0b4353654
commit ea1bd74def
49 changed files with 711 additions and 22 deletions

View File

@ -1,3 +1,62 @@
2016-12-16 Zack Weinberg <zackw@panix.com>
Florian Weimer <fweimer@redhat.com>
Nick Mathewson <nickm@torproject.org>
* string/explicit_bzero.c: New routine.
* string/test-explicit_bzero.c, string/tst-xbzero-opt.c: New tests.
* string/Makefile (routines, strop-tests, tests): Add them.
* string/test-memset.c: Add ifdeffage for testing explicit_bzero.
* string/string.h [__USE_MISC]: Declare explicit_bzero.
* debug/explicit_bzero_chk.c: New routine.
* debug/Makefile (routines): Add it.
* debug/tst-chk1.c: Test fortification of explicit_bzero.
* string/bits/string3.h: Fortify explicit_bzero.
* manual/string.texi: Document explicit_bzero.
* NEWS: Mention addition of explicit_bzero.
* crypt/crypt-entry.c (__crypt_r): Clear key-dependent intermediate
data before returning, using explicit_bzero.
* crypt/md5-crypt.c (__md5_crypt_r): Likewise.
* crypt/sha256-crypt.c (__sha256_crypt_r): Likewise.
* crypt/sha512-crypt.c (__sha512_crypt_r): Likewise.
* include/string.h: Redirect internal uses of explicit_bzero
to __explicit_bzero_chk[_internal].
* string/Versions [GLIBC_2.25]: Add explicit_bzero.
* debug/Versions [GLIBC_2.25]: Add __explicit_bzero_chk.
* sysdeps/arm/nacl/libc.abilist
* sysdeps/unix/sysv/linux/aarch64/libc.abilist
* sysdeps/unix/sysv/linux/alpha/libc.abilist
* sysdeps/unix/sysv/linux/arm/libc.abilist
* sysdeps/unix/sysv/linux/hppa/libc.abilist
* sysdeps/unix/sysv/linux/i386/libc.abilist
* sysdeps/unix/sysv/linux/ia64/libc.abilist
* sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist
* sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist
* sysdeps/unix/sysv/linux/microblaze/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist
* sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist
* sysdeps/unix/sysv/linux/nios2/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist
* sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist
* sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist
* sysdeps/unix/sysv/linux/sh/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist
* sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist
* sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/64/libc.abilist
* sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist:
Add entries for explicit_bzero and __explicit_bzero_chk.
2016-12-16 Joseph Myers <joseph@codesourcery.com>
* math/fenv.h

6
NEWS
View File

@ -84,6 +84,12 @@ Version 2.25
* The functions strfromd, strfromf, and strfroml, from ISO/IEC TS 18661-1:2014,
are added to libc. They convert a floating-point number into string.
* The function explicit_bzero, from OpenBSD, has been added to libc. It is
intended to be used instead of memset() to erase sensitive data after use;
the compiler will not optimize out calls to explicit_bzero even if they
are "unnecessary" (in the sense that no _correct_ program can observe the
effects of the memory clear).
* On ColdFire, MicroBlaze, Nios II and SH3, the float_t type is now defined
to float instead of double. This does not affect the ABI of any libraries
that are part of the GNU C Library, but may affect the ABI of other

View File

@ -141,6 +141,15 @@ __crypt_r (const char *key, const char *salt,
* And convert back to 6 bit ASCII
*/
_ufc_output_conversion_r (res[0], res[1], salt, data);
/*
* Erase key-dependent intermediate data. Data dependent only on
* the salt is not considered sensitive.
*/
explicit_bzero (ktab, sizeof (ktab));
explicit_bzero (data->keysched, sizeof (data->keysched));
explicit_bzero (res, sizeof (res));
return data->crypt_3_buf;
}
weak_alias (__crypt_r, crypt_r)

View File

@ -288,13 +288,13 @@ __md5_crypt_r (const char *key, const char *salt, char *buffer, int buflen)
#ifndef USE_NSS
__md5_init_ctx (&ctx);
__md5_finish_ctx (&ctx, alt_result);
memset (&ctx, '\0', sizeof (ctx));
memset (&alt_ctx, '\0', sizeof (alt_ctx));
explicit_bzero (&ctx, sizeof (ctx));
explicit_bzero (&alt_ctx, sizeof (alt_ctx));
#endif
if (copied_key != NULL)
memset (copied_key, '\0', key_len);
explicit_bzero (copied_key, key_len);
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
explicit_bzero (copied_salt, salt_len);
free (free_key);
return buffer;

View File

@ -371,16 +371,16 @@ __sha256_crypt_r (const char *key, const char *salt, char *buffer, int buflen)
#ifndef USE_NSS
__sha256_init_ctx (&ctx);
__sha256_finish_ctx (&ctx, alt_result);
memset (&ctx, '\0', sizeof (ctx));
memset (&alt_ctx, '\0', sizeof (alt_ctx));
explicit_bzero (&ctx, sizeof (ctx));
explicit_bzero (&alt_ctx, sizeof (alt_ctx));
#endif
memset (temp_result, '\0', sizeof (temp_result));
memset (p_bytes, '\0', key_len);
memset (s_bytes, '\0', salt_len);
explicit_bzero (temp_result, sizeof (temp_result));
explicit_bzero (p_bytes, key_len);
explicit_bzero (s_bytes, salt_len);
if (copied_key != NULL)
memset (copied_key, '\0', key_len);
explicit_bzero (copied_key, key_len);
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
explicit_bzero (copied_salt, salt_len);
free (free_key);
free (free_pbytes);

View File

@ -393,16 +393,16 @@ __sha512_crypt_r (const char *key, const char *salt, char *buffer, int buflen)
#ifndef USE_NSS
__sha512_init_ctx (&ctx);
__sha512_finish_ctx (&ctx, alt_result);
memset (&ctx, '\0', sizeof (ctx));
memset (&alt_ctx, '\0', sizeof (alt_ctx));
explicit_bzero (&ctx, sizeof (ctx));
explicit_bzero (&alt_ctx, sizeof (alt_ctx));
#endif
memset (temp_result, '\0', sizeof (temp_result));
memset (p_bytes, '\0', key_len);
memset (s_bytes, '\0', salt_len);
explicit_bzero (temp_result, sizeof (temp_result));
explicit_bzero (p_bytes, key_len);
explicit_bzero (s_bytes, salt_len);
if (copied_key != NULL)
memset (copied_key, '\0', key_len);
explicit_bzero (copied_key, key_len);
if (copied_salt != NULL)
memset (copied_salt, '\0', salt_len);
explicit_bzero (copied_salt, salt_len);
free (free_key);
free (free_pbytes);

View File

@ -48,6 +48,7 @@ routines = backtrace backtracesyms backtracesymsfd noophooks \
vdprintf_chk obprintf_chk \
longjmp_chk ____longjmp_chk \
fdelt_chk poll_chk ppoll_chk \
explicit_bzero_chk \
stack_chk_fail fortify_fail \
$(static-only-routines)
static-only-routines := warning-nop stack_chk_fail_local

View File

@ -55,6 +55,9 @@ libc {
GLIBC_2.16 {
__poll_chk; __ppoll_chk;
}
GLIBC_2.25 {
__explicit_bzero_chk;
}
GLIBC_PRIVATE {
__fortify_fail;
}

View File

@ -0,0 +1,44 @@
/* Generic implementation of __explicit_bzero_chk.
Copyright (C) 1991-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Torbjorn Granlund (tege@sics.se).
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
<http://www.gnu.org/licenses/>. */
/* This is the generic definition of __explicit_bzero_chk. The
__explicit_bzero_chk symbol is used as the implementation of
explicit_bzero throughout glibc. If this file is overriden by an
architecture, both __explicit_bzero_chk and
__explicit_bzero_chk_internal have to be defined (the latter not as
an IFUNC). */
#include <string.h>
void
__explicit_bzero_chk (void *dst, size_t len, size_t dstlen)
{
/* Inline __memset_chk to avoid a PLT reference to __memset_chk. */
if (__glibc_unlikely (dstlen < len))
__chk_fail ();
memset (dst, '\0', len);
/* Compiler barrier. */
asm volatile ("" ::: "memory");
}
/* libc-internal references use the hidden
__explicit_bzero_chk_internal symbol. This is necessary if
__explicit_bzero_chk is implemented as an IFUNC because some
targets do not support hidden references to IFUNC symbols. */
strong_alias (__explicit_bzero_chk, __explicit_bzero_chk_internal)

View File

@ -160,6 +160,10 @@ do_test (void)
if (memcmp (buf, "aabcdabc\0\0", 10))
FAIL ();
explicit_bzero (buf + 6, 4);
if (memcmp (buf, "aabcda\0\0\0\0", 10))
FAIL ();
strcpy (buf + 4, "EDCBA");
if (memcmp (buf, "aabcEDCBA", 10))
FAIL ();
@ -201,6 +205,10 @@ do_test (void)
if (memcmp (buf, "aabcdabc\0\0", 10))
FAIL ();
explicit_bzero (buf + 6, l0 + 4);
if (memcmp (buf, "aabcda\0\0\0\0", 10))
FAIL ();
strcpy (buf + 4, str1 + 5);
if (memcmp (buf, "aabcEDCBA", 10))
FAIL ();
@ -256,6 +264,10 @@ do_test (void)
if (memcmp (a.buf1, "aabcdabc\0\0", 10))
FAIL ();
explicit_bzero (a.buf1 + 6, l0 + 4);
if (memcmp (a.buf1, "aabcda\0\0\0\0", 10))
FAIL ();
#if __USE_FORTIFY_LEVEL < 2
/* The following tests are supposed to crash with -D_FORTIFY_SOURCE=2
and sufficient GCC support, as the string operations overflow
@ -345,6 +357,14 @@ do_test (void)
bzero (buf + 9, l0 + 2);
CHK_FAIL_END
CHK_FAIL_START
explicit_bzero (buf + 9, 2);
CHK_FAIL_END
CHK_FAIL_START
explicit_bzero (buf + 9, l0 + 2);
CHK_FAIL_END
CHK_FAIL_START
strcpy (buf + 5, str1 + 5);
CHK_FAIL_END
@ -454,6 +474,14 @@ do_test (void)
bzero (a.buf1 + 9, l0 + 2);
CHK_FAIL_END
CHK_FAIL_START
explicit_bzero (a.buf1 + 9, 2);
CHK_FAIL_END
CHK_FAIL_START
explicit_bzero (a.buf1 + 9, l0 + 2);
CHK_FAIL_END
# if __USE_FORTIFY_LEVEL >= 2
# define O 0
# else

View File

@ -100,6 +100,17 @@ extern __typeof (memmem) __memmem;
libc_hidden_proto (__memmem)
libc_hidden_proto (__ffs)
#if IS_IN (libc)
/* Avoid hidden reference to IFUNC symbol __explicit_bzero_chk. */
void __explicit_bzero_chk_internal (void *, size_t, size_t)
__THROW __nonnull ((1)) attribute_hidden;
# define explicit_bzero(buf, len) \
__explicit_bzero_chk_internal (buf, len, __bos0 (buf))
#elif !IS_IN (nonlib)
void __explicit_bzero_chk (void *, size_t, size_t) __THROW __nonnull ((1));
# define explicit_bzero(buf, len) __explicit_bzero_chk (buf, len, __bos0 (buf))
#endif
libc_hidden_builtin_proto (memchr)
libc_hidden_builtin_proto (memcpy)
libc_hidden_builtin_proto (mempcpy)

View File

@ -34,6 +34,8 @@ too.
* Search Functions:: Searching for a specific element or substring.
* Finding Tokens in a String:: Splitting a string into tokens by looking
for delimiters.
* Erasing Sensitive Data:: Clearing memory which contains sensitive
data, after it's no longer needed.
* strfry:: Function for flash-cooking a string.
* Trivial Encryption:: Obscuring data.
* Encode Binary Data:: Encoding and Decoding of Binary Data.
@ -2404,6 +2406,103 @@ contains no '/' bytes, then "." is returned. The prototype for this
function can be found in @file{libgen.h}.
@end deftypefun
@node Erasing Sensitive Data
@section Erasing Sensitive Data
Sensitive data, such as cryptographic keys, should be erased from
memory after use, to reduce the risk that a bug will expose it to the
outside world. However, compiler optimizations may determine that an
erasure operation is ``unnecessary,'' and remove it from the generated
code, because no @emph{correct} program could access the variable or
heap object containing the sensitive data after it's deallocated.
Since erasure is a precaution against bugs, this optimization is
inappropriate.
The function @code{explicit_bzero} erases a block of memory, and
guarantees that the compiler will not remove the erasure as
``unnecessary.''
@smallexample
@group
#include <string.h>
extern void encrypt (const char *key, const char *in,
char *out, size_t n);
extern void genkey (const char *phrase, char *key);
void encrypt_with_phrase (const char *phrase, const char *in,
char *out, size_t n)
@{
char key[16];
genkey (phrase, key);
encrypt (key, in, out, n);
explicit_bzero (key, 16);
@}
@end group
@end smallexample
@noindent
In this example, if @code{memset}, @code{bzero}, or a hand-written
loop had been used, the compiler might remove them as ``unnecessary.''
@strong{Warning:} @code{explicit_bzero} does not guarantee that
sensitive data is @emph{completely} erased from the computer's memory.
There may be copies in temporary storage areas, such as registers and
``scratch'' stack space; since these are invisible to the source code,
a library function cannot erase them.
Also, @code{explicit_bzero} only operates on RAM. If a sensitive data
object never needs to have its address taken other than to call
@code{explicit_bzero}, it might be stored entirely in CPU registers
@emph{until} the call to @code{explicit_bzero}. Then it will be
copied into RAM, the copy will be erased, and the original will remain
intact. Data in RAM is more likely to be exposed by a bug than data
in registers, so this creates a brief window where the data is at
greater risk of exposure than it would have been if the program didn't
try to erase it at all.
Declaring sensitive variables as @code{volatile} will make both the
above problems @emph{worse}; a @code{volatile} variable will be stored
in memory for its entire lifetime, and the compiler will make
@emph{more} copies of it than it would otherwise have. Attempting to
erase a normal variable ``by hand'' through a
@code{volatile}-qualified pointer doesn't work at all---because the
variable itself is not @code{volatile}, some compilers will ignore the
qualification on the pointer and remove the erasure anyway.
Having said all that, in most situations, using @code{explicit_bzero}
is better than not using it. At present, the only way to do a more
thorough job is to write the entire sensitive operation in assembly
language. We anticipate that future compilers will recognize calls to
@code{explicit_bzero} and take appropriate steps to erase all the
copies of the affected data, whereever they may be.
@comment string.h
@comment BSD
@deftypefun void explicit_bzero (void *@var{block}, size_t @var{len})
@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
@code{explicit_bzero} writes zero into @var{len} bytes of memory
beginning at @var{block}, just as @code{bzero} would. The zeroes are
always written, even if the compiler could determine that this is
``unnecessary'' because no correct program could read them back.
@strong{Note:} The @emph{only} optimization that @code{explicit_bzero}
disables is removal of ``unnecessary'' writes to memory. The compiler
can perform all the other optimizations that it could for a call to
@code{memset}. For instance, it may replace the function call with
inline memory writes, and it may assume that @var{block} cannot be a
null pointer.
@strong{Portability Note:} This function first appeared in OpenBSD 5.5
and has not been standardized. Other systems may provide the same
functionality under a different name, such as @code{explicit_memset},
@code{memset_s}, or @code{SecureZeroMemory}.
@Theglibc{} declares this function in @file{string.h}, but on other
systems it may be in @file{strings.h} instead.
@end deftypefun
@node strfry
@section strfry

View File

@ -41,20 +41,21 @@ routines := strcat strchr strcmp strcoll strcpy strcspn \
addsep replace) \
envz basename \
strcoll_l strxfrm_l string-inlines memrchr \
xpg-strerror strerror_l
xpg-strerror strerror_l explicit_bzero
strop-tests := memchr memcmp memcpy memmove mempcpy memset memccpy \
stpcpy stpncpy strcat strchr strcmp strcpy strcspn \
strlen strncmp strncpy strpbrk strrchr strspn memmem \
strstr strcasestr strnlen strcasecmp strncasecmp \
strncat rawmemchr strchrnul bcopy bzero memrchr
strncat rawmemchr strchrnul bcopy bzero memrchr \
explicit_bzero
tests := tester inl-tester noinl-tester testcopy test-ffs \
tst-strlen stratcliff tst-svc tst-inlcall \
bug-strncat1 bug-strspn1 bug-strpbrk1 tst-bswap \
tst-strtok tst-strxfrm bug-strcoll1 tst-strfry \
bug-strtok1 $(addprefix test-,$(strop-tests)) \
bug-envz1 tst-strxfrm2 tst-endian tst-svc2 \
tst-strtok_r bug-strcoll2 tst-cmp
tst-strtok_r bug-strcoll2 tst-cmp tst-xbzero-opt
xtests = tst-strcoll-overflow

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@ -82,4 +82,7 @@ libc {
}
GLIBC_2.24 {
}
GLIBC_2.25 {
explicit_bzero;
}
}

View File

@ -102,6 +102,15 @@ __NTH (bzero (void *__dest, size_t __len))
{
(void) __builtin___memset_chk (__dest, '\0', __len, __bos0 (__dest));
}
void __explicit_bzero_chk (void *__dest, size_t __len, size_t __destlen)
__THROW __nonnull ((1));
__fortify_function void
__NTH (explicit_bzero (void *__dest, size_t __len))
{
__explicit_bzero_chk (__dest, __len, __bos0 (__dest));
}
#endif
__fortify_function char *

38
string/explicit_bzero.c Normal file
View File

@ -0,0 +1,38 @@
/* Erasure of sensitive data, generic implementation.
Copyright (C) 2016 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
<http://www.gnu.org/licenses/>. */
/* An assembler implementation of explicit_bzero can be created as an
assembler alias of an optimized bzero implementation.
Architecture-specific implementations also need to define
__explicit_bzero_chk. */
#include <string.h>
/* glibc-internal users use __explicit_bzero_chk, and explicit_bzero
redirects to that. */
#undef explicit_bzero
/* Set LEN bytes of S to 0. The compiler will not delete a call to
this function, even if S is dead after the call. */
void
explicit_bzero (void *s, size_t len)
{
memset (s, '\0', len);
/* Compiler barrier. */
asm volatile ("" ::: "memory");
}

View File

@ -453,6 +453,10 @@ extern void bcopy (const void *__src, void *__dest, size_t __n)
/* Set N bytes of S to 0. */
extern void bzero (void *__s, size_t __n) __THROW __nonnull ((1));
/* As bzero, but the compiler will not delete a call to this
function, even if S is dead after the call. */
extern void explicit_bzero (void *__s, size_t __n) __THROW __nonnull ((1));
/* Compare N bytes of S1 and S2 (same as memcmp). */
extern int bcmp (const void *__s1, const void *__s2, size_t __n)
__THROW __attribute_pure__ __nonnull ((1, 2));

View File

@ -0,0 +1,20 @@
/* Test and measure explicit_bzero.
Copyright (C) 2016 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
<http://www.gnu.org/licenses/>. */
#define TEST_EXPLICIT_BZERO
#define TEST_BZERO
#include "test-memset.c"

View File

@ -19,7 +19,11 @@
#define TEST_MAIN
#ifdef TEST_BZERO
# define TEST_NAME "bzero"
# ifdef TEST_EXPLICIT_BZERO
# define TEST_NAME "explicit_bzero"
# else
# define TEST_NAME "bzero"
# endif
#else
# ifndef WIDE
# define TEST_NAME "memset"
@ -56,7 +60,11 @@ void builtin_bzero (char *, size_t);
IMPL (simple_bzero, 0)
IMPL (builtin_bzero, 0)
#ifdef TEST_EXPLICIT_BZERO
IMPL (explicit_bzero, 1)
#else
IMPL (bzero, 1)
#endif
void
simple_bzero (char *s, size_t n)

288
string/tst-xbzero-opt.c Normal file
View File

@ -0,0 +1,288 @@
/* Test that explicit_bzero block clears are not optimized out.
Copyright (C) 2016 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
<http://www.gnu.org/licenses/>. */
/* This test is conceptually based on a test designed by Matthew
Dempsky for the OpenBSD regression suite:
<openbsd>/src/regress/lib/libc/explicit_bzero/explicit_bzero.c.
The basic idea is, we have a function that contains a
block-clearing operation (not necessarily explicit_bzero), after
which the block is dead, in the compiler-jargon sense. Execute
that function while running on a user-allocated alternative
stack. Then we have another pointer to the memory region affected
by the block clear -- namely, the original allocation for the
alternative stack -- and can find out whether it actually happened.
The OpenBSD test uses sigaltstack and SIGUSR1 to get onto an
alternative stack. This causes a number of awkward problems; some
operating systems (e.g. Solaris and OSX) wipe the signal stack upon
returning to the normal stack, there's no way to be sure that other
processes running on the same system will not interfere, and the
signal stack is very small so it's not safe to call printf there.
This implementation instead uses the <ucontext.h> coroutine
interface. The coroutine stack is still too small to safely use
printf, but we know the OS won't erase it, so we can do all the
checks and printing from the normal stack. */
#define _GNU_SOURCE 1
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ucontext.h>
#include <unistd.h>
/* A byte pattern that is unlikely to occur by chance: the first 16
prime numbers (OEIS A000040). */
static const unsigned char test_pattern[16] =
{
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53
};
/* Immediately after each subtest returns, we call swapcontext to get
back onto the main stack. That call might itself overwrite the
test pattern, so we fill a modest-sized buffer with copies of it
and check whether any of them survived. */
#define PATTERN_SIZE (sizeof test_pattern)
#define PATTERN_REPS 32
#define TEST_BUFFER_SIZE (PATTERN_SIZE * PATTERN_REPS)
/* There are three subtests, two of which are sanity checks.
Each test follows this sequence:
main coroutine
---- --------
advance cur_subtest
swap
call setup function
prepare test buffer
swap
verify that buffer
was filled in
swap
possibly clear buffer
return
swap
check buffer again,
according to test
expectation
In the "no_clear" case, we don't do anything to the test buffer
between preparing it and letting it go out of scope, and we expect
to find it. This confirms that the test buffer does get filled in
and we can find it from the stack buffer. In the "ordinary_clear"
case, we clear it using memset, and we expect to find it. This
confirms that the compiler can optimize out block clears in this
context; if it can't, the real test might be succeeding for the
wrong reason. Finally, the "explicit_clear" case uses
explicit_bzero and expects _not_ to find the test buffer, which is
the real test. */
static ucontext_t uc_main, uc_co;
/* Always check the test buffer immediately after filling it; this
makes externally visible side effects depend on the buffer existing
and having been filled in. */
static void
prepare_test_buffer (unsigned char *buf)
{
for (unsigned int i = 0; i < PATTERN_REPS; i++)
memcpy (buf + i*PATTERN_SIZE, test_pattern, PATTERN_SIZE);
if (swapcontext (&uc_co, &uc_main))
abort ();
}
static void
setup_no_clear (void)
{
unsigned char buf[TEST_BUFFER_SIZE];
prepare_test_buffer (buf);
}
static void
setup_ordinary_clear (void)
{
unsigned char buf[TEST_BUFFER_SIZE];
prepare_test_buffer (buf);
memset (buf, 0, TEST_BUFFER_SIZE);
}
static void
setup_explicit_clear (void)
{
unsigned char buf[TEST_BUFFER_SIZE];
prepare_test_buffer (buf);
explicit_bzero (buf, TEST_BUFFER_SIZE);
}
enum test_expectation { EXPECT_NONE, EXPECT_SOME, EXPECT_ALL };
struct subtest
{
void (*setup_subtest) (void);
const char *label;
enum test_expectation expected;
};
static const struct subtest *cur_subtest;
static const struct subtest subtests[] =
{
{ setup_no_clear, "no clear", EXPECT_SOME },
{ setup_ordinary_clear, "ordinary clear", EXPECT_SOME },
{ setup_explicit_clear, "explicit clear", EXPECT_NONE },
{ 0, 0, -1 }
};
static void
test_coroutine (void)
{
while (cur_subtest->setup_subtest)
{
cur_subtest->setup_subtest ();
if (swapcontext (&uc_co, &uc_main))
abort ();
}
}
/* All the code above this point runs on the coroutine stack.
All the code below this point runs on the main stack. */
static int test_status;
static unsigned char *co_stack_buffer;
static size_t co_stack_size;
static unsigned int
count_test_patterns (unsigned char *buf, size_t bufsiz)
{
unsigned char *first = memmem (buf, bufsiz, test_pattern, PATTERN_SIZE);
if (!first)
return 0;
unsigned int cnt = 0;
for (unsigned int i = 0; i < PATTERN_REPS; i++)
{
unsigned char *p = first + i*PATTERN_SIZE;
if (p + PATTERN_SIZE - buf > bufsiz)
break;
if (memcmp (p, test_pattern, PATTERN_SIZE) == 0)
cnt++;
}
return cnt;
}
static void
check_test_buffer (enum test_expectation expected,
const char *label, const char *stage)
{
unsigned int cnt = count_test_patterns (co_stack_buffer, co_stack_size);
switch (expected)
{
case EXPECT_NONE:
if (cnt == 0)
printf ("PASS: %s/%s: expected 0 got %d\n", label, stage, cnt);
else
{
printf ("FAIL: %s/%s: expected 0 got %d\n", label, stage, cnt);
test_status = 1;
}
break;
case EXPECT_SOME:
if (cnt > 0)
printf ("PASS: %s/%s: expected some got %d\n", label, stage, cnt);
else
{
printf ("FAIL: %s/%s: expected some got 0\n", label, stage);
test_status = 1;
}
break;
case EXPECT_ALL:
if (cnt == PATTERN_REPS)
printf ("PASS: %s/%s: expected %d got %d\n", label, stage,
PATTERN_REPS, cnt);
else
{
printf ("FAIL: %s/%s: expected %d got %d\n", label, stage,
PATTERN_REPS, cnt);
test_status = 1;
}
break;
default:
printf ("ERROR: %s/%s: invalid value for 'expected' = %d\n",
label, stage, (int)expected);
test_status = 1;
}
}
static void
test_loop (void)
{
cur_subtest = subtests;
while (cur_subtest->setup_subtest)
{
if (swapcontext (&uc_main, &uc_co))
abort ();
check_test_buffer (EXPECT_ALL, cur_subtest->label, "prepare");
if (swapcontext (&uc_main, &uc_co))
abort ();
check_test_buffer (cur_subtest->expected, cur_subtest->label, "test");
cur_subtest++;
}
/* Terminate the coroutine. */
if (swapcontext (&uc_main, &uc_co))
abort ();
}
int
do_test (void)
{
size_t page_alignment = sysconf (_SC_PAGESIZE);
if (page_alignment < sizeof (void *))
page_alignment = sizeof (void *);
co_stack_size = SIGSTKSZ + TEST_BUFFER_SIZE;
if (co_stack_size < page_alignment * 4)
co_stack_size = page_alignment * 4;
void *p;
int err = posix_memalign (&p, page_alignment, co_stack_size);
if (err || !p)
{
printf ("ERROR: allocating alt stack: %s\n", strerror (err));
return 2;
}
co_stack_buffer = p;
if (getcontext (&uc_co))
{
printf ("ERROR: allocating coroutine context: %s\n", strerror (err));
return 2;
}
uc_co.uc_stack.ss_sp = co_stack_buffer;
uc_co.uc_stack.ss_size = co_stack_size;
uc_co.uc_link = &uc_main;
makecontext (&uc_co, test_coroutine, 0);
test_loop ();
return test_status;
}
#include <support/test-driver.c>

View File

@ -1843,6 +1843,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 gnu_dev_major F

View File

@ -2090,6 +2090,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2001,6 +2001,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -91,6 +91,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1855,6 +1855,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2013,6 +2013,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1877,6 +1877,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -92,6 +92,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1969,6 +1969,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2090,6 +2090,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1944,6 +1944,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1942,6 +1942,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1940,6 +1940,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1935,6 +1935,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2131,6 +2131,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1973,6 +1973,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1978,6 +1978,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2178,6 +2178,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -92,6 +92,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1973,6 +1973,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1874,6 +1874,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1859,6 +1859,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1965,6 +1965,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1903,6 +1903,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2097,6 +2097,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2097,6 +2097,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2097,6 +2097,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -1854,6 +1854,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F

View File

@ -2097,6 +2097,8 @@ GLIBC_2.23 fts64_set F
GLIBC_2.24 GLIBC_2.24 A
GLIBC_2.24 quick_exit F
GLIBC_2.25 GLIBC_2.25 A
GLIBC_2.25 __explicit_bzero_chk F
GLIBC_2.25 explicit_bzero F
GLIBC_2.25 getentropy F
GLIBC_2.25 getrandom F
GLIBC_2.25 strfromd F