* [PATCH] x86-64 strncat: Properly handle the length parameter [BZ# 24097]
@ 2022-12-02 0:37 H.J. Lu
2022-12-02 1:39 ` Noah Goldstein
0 siblings, 1 reply; 2+ messages in thread
From: H.J. Lu @ 2022-12-02 0:37 UTC (permalink / raw)
To: libc-alpha; +Cc: Noah Goldstein
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes strncat for x32. Tested on x86-64 and x32. On x86-64,
libc.so is the same with and without the fix.
---
.../x86_64/multiarch/strcat-sse2-unaligned.S | 4 ++
sysdeps/x86_64/multiarch/strncat-avx2.S | 4 ++
sysdeps/x86_64/multiarch/strncat-evex.S | 5 ++
sysdeps/x86_64/x32/Makefile | 2 +-
sysdeps/x86_64/x32/tst-size_t-strncat.c | 59 +++++++++++++++++++
5 files changed, 73 insertions(+), 1 deletion(-)
create mode 100644 sysdeps/x86_64/x32/tst-size_t-strncat.c
diff --git a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
index 9d2ca1d504..b0f9c5fa83 100644
--- a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
+++ b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
@@ -35,6 +35,10 @@
ENTRY (STRCAT)
mov %rdi, %r9
# ifdef USE_AS_STRNCAT
+# ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+# endif
mov %rdx, %r8
# endif
diff --git a/sysdeps/x86_64/multiarch/strncat-avx2.S b/sysdeps/x86_64/multiarch/strncat-avx2.S
index ffa58bd0de..73baeee473 100644
--- a/sysdeps/x86_64/multiarch/strncat-avx2.S
+++ b/sysdeps/x86_64/multiarch/strncat-avx2.S
@@ -51,6 +51,10 @@
.section SECTION(.text), "ax", @progbits
ENTRY(STRNCAT)
+# ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+# endif
/* Filter zero length strings and very long strings. Zero
length strings just return, very long strings are handled by
using the non-length variant {wcs|str}cat. */
diff --git a/sysdeps/x86_64/multiarch/strncat-evex.S b/sysdeps/x86_64/multiarch/strncat-evex.S
index bced4e8944..1ef3a22209 100644
--- a/sysdeps/x86_64/multiarch/strncat-evex.S
+++ b/sysdeps/x86_64/multiarch/strncat-evex.S
@@ -79,6 +79,11 @@
.section SECTION(.text), "ax", @progbits
ENTRY(STRNCAT)
+# ifdef __ILP32__
+ /* Clear the upper 32 bits. */
+ movl %edx, %edx
+# endif
+
movq %rdi, %rax
/* NB: It's safe to filter out zero-length strings WITHOUT
diff --git a/sysdeps/x86_64/x32/Makefile b/sysdeps/x86_64/x32/Makefile
index 31732aa248..a015789a4f 100644
--- a/sysdeps/x86_64/x32/Makefile
+++ b/sysdeps/x86_64/x32/Makefile
@@ -10,7 +10,7 @@ ifeq ($(subdir),string)
tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \
tst-size_t-memrchr tst-size_t-memset tst-size_t-strncasecmp \
tst-size_t-strncmp tst-size_t-strncpy tst-size_t-strnlen \
- tst-size_t-memcmp-2
+ tst-size_t-memcmp-2 tst-size_t-strncat
endif
ifeq ($(subdir),wcsmbs)
diff --git a/sysdeps/x86_64/x32/tst-size_t-strncat.c b/sysdeps/x86_64/x32/tst-size_t-strncat.c
new file mode 100644
index 0000000000..eda93f5af9
--- /dev/null
+++ b/sysdeps/x86_64/x32/tst-size_t-strncat.c
@@ -0,0 +1,59 @@
+/* Test strncat with size_t in the lower 32 bits of 64-bit register.
+ Copyright (C) 2022 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/>. */
+
+#define TEST_NAME "strncat"
+#include "test-size_t.h"
+
+IMPL (strncat, 1)
+
+typedef char *(*proto_t) (char *, const char*, size_t);
+
+static void *
+__attribute__ ((noinline, noclone))
+do_strncat (parameter_t a, parameter_t b)
+{
+ return CALL (&b, a.p, b.p, a.len);
+}
+
+static int
+test_main (void)
+{
+ test_init ();
+
+ parameter_t dest = { { page_size - 1 }, buf1 };
+ parameter_t src = { { 0 }, buf2 };
+
+ int ret = 0;
+ FOR_EACH_IMPL (impl, 0)
+ {
+ src.fn = impl->fn;
+ buf1[0] = '\0';
+ do_strncat (dest, src);
+ int res = strncmp (dest.p, src.p, dest.len);
+ if (res)
+ {
+ error (0, 0, "Wrong result in function %s: %i != 0",
+ impl->name, res);
+ ret = 1;
+ }
+ }
+
+ return ret ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
--
2.38.1
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] x86-64 strncat: Properly handle the length parameter [BZ# 24097]
2022-12-02 0:37 [PATCH] x86-64 strncat: Properly handle the length parameter [BZ# 24097] H.J. Lu
@ 2022-12-02 1:39 ` Noah Goldstein
0 siblings, 0 replies; 2+ messages in thread
From: Noah Goldstein @ 2022-12-02 1:39 UTC (permalink / raw)
To: H.J. Lu; +Cc: libc-alpha
On Thu, Dec 1, 2022 at 4:37 PM H.J. Lu <hjl.tools@gmail.com> wrote:
>
> On x32, the size_t parameter may be passed in the lower 32 bits of a
> 64-bit register with the non-zero upper 32 bits. The string/memory
> functions written in assembly can only use the lower 32 bits of a
> 64-bit register as length or must clear the upper 32 bits before using
> the full 64-bit register for length.
>
> This pach fixes strncat for x32. Tested on x86-64 and x32. On x86-64,
> libc.so is the same with and without the fix.
> ---
> .../x86_64/multiarch/strcat-sse2-unaligned.S | 4 ++
> sysdeps/x86_64/multiarch/strncat-avx2.S | 4 ++
> sysdeps/x86_64/multiarch/strncat-evex.S | 5 ++
> sysdeps/x86_64/x32/Makefile | 2 +-
> sysdeps/x86_64/x32/tst-size_t-strncat.c | 59 +++++++++++++++++++
> 5 files changed, 73 insertions(+), 1 deletion(-)
> create mode 100644 sysdeps/x86_64/x32/tst-size_t-strncat.c
>
> diff --git a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
> index 9d2ca1d504..b0f9c5fa83 100644
> --- a/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
> +++ b/sysdeps/x86_64/multiarch/strcat-sse2-unaligned.S
> @@ -35,6 +35,10 @@
> ENTRY (STRCAT)
> mov %rdi, %r9
> # ifdef USE_AS_STRNCAT
> +# ifdef __ILP32__
> + /* Clear the upper 32 bits. */
> + movl %edx, %edx
> +# endif
> mov %rdx, %r8
> # endif
>
> diff --git a/sysdeps/x86_64/multiarch/strncat-avx2.S b/sysdeps/x86_64/multiarch/strncat-avx2.S
> index ffa58bd0de..73baeee473 100644
> --- a/sysdeps/x86_64/multiarch/strncat-avx2.S
> +++ b/sysdeps/x86_64/multiarch/strncat-avx2.S
> @@ -51,6 +51,10 @@
>
> .section SECTION(.text), "ax", @progbits
> ENTRY(STRNCAT)
> +# ifdef __ILP32__
> + /* Clear the upper 32 bits. */
> + movl %edx, %edx
> +# endif
> /* Filter zero length strings and very long strings. Zero
> length strings just return, very long strings are handled by
> using the non-length variant {wcs|str}cat. */
> diff --git a/sysdeps/x86_64/multiarch/strncat-evex.S b/sysdeps/x86_64/multiarch/strncat-evex.S
> index bced4e8944..1ef3a22209 100644
> --- a/sysdeps/x86_64/multiarch/strncat-evex.S
> +++ b/sysdeps/x86_64/multiarch/strncat-evex.S
> @@ -79,6 +79,11 @@
>
> .section SECTION(.text), "ax", @progbits
> ENTRY(STRNCAT)
> +# ifdef __ILP32__
> + /* Clear the upper 32 bits. */
> + movl %edx, %edx
> +# endif
> +
> movq %rdi, %rax
>
> /* NB: It's safe to filter out zero-length strings WITHOUT
> diff --git a/sysdeps/x86_64/x32/Makefile b/sysdeps/x86_64/x32/Makefile
> index 31732aa248..a015789a4f 100644
> --- a/sysdeps/x86_64/x32/Makefile
> +++ b/sysdeps/x86_64/x32/Makefile
> @@ -10,7 +10,7 @@ ifeq ($(subdir),string)
> tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \
> tst-size_t-memrchr tst-size_t-memset tst-size_t-strncasecmp \
> tst-size_t-strncmp tst-size_t-strncpy tst-size_t-strnlen \
> - tst-size_t-memcmp-2
> + tst-size_t-memcmp-2 tst-size_t-strncat
> endif
>
> ifeq ($(subdir),wcsmbs)
> diff --git a/sysdeps/x86_64/x32/tst-size_t-strncat.c b/sysdeps/x86_64/x32/tst-size_t-strncat.c
> new file mode 100644
> index 0000000000..eda93f5af9
> --- /dev/null
> +++ b/sysdeps/x86_64/x32/tst-size_t-strncat.c
> @@ -0,0 +1,59 @@
> +/* Test strncat with size_t in the lower 32 bits of 64-bit register.
> + Copyright (C) 2022 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/>. */
> +
> +#define TEST_NAME "strncat"
> +#include "test-size_t.h"
> +
> +IMPL (strncat, 1)
> +
> +typedef char *(*proto_t) (char *, const char*, size_t);
> +
> +static void *
> +__attribute__ ((noinline, noclone))
> +do_strncat (parameter_t a, parameter_t b)
> +{
> + return CALL (&b, a.p, b.p, a.len);
> +}
> +
> +static int
> +test_main (void)
> +{
> + test_init ();
> +
> + parameter_t dest = { { page_size - 1 }, buf1 };
> + parameter_t src = { { 0 }, buf2 };
> +
> + int ret = 0;
> + FOR_EACH_IMPL (impl, 0)
> + {
> + src.fn = impl->fn;
> + buf1[0] = '\0';
> + do_strncat (dest, src);
> + int res = strncmp (dest.p, src.p, dest.len);
> + if (res)
> + {
> + error (0, 0, "Wrong result in function %s: %i != 0",
> + impl->name, res);
> + ret = 1;
> + }
> + }
> +
> + return ret ? EXIT_FAILURE : EXIT_SUCCESS;
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.38.1
>
LGTM.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
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