printstr_ex: fix decoding of non-NUL-terminated strings when len == -1

Do not treat len == -1 in any special way.  All users who need the
string to be handled as a NUL-terminated string set QUOTE_0_TERMINATED
bit in user_style flags already.

* util.c (printstr_ex): Remove (len == -1) check.
* tests/printstr.c: New file.
* tests/printstr.test: New test.
* tests/.gitignore: Add printstr.
* tests/Makefile.am (check_PROGRAMS): Likewise.
(DECODER_TESTS): Add printstr.test.
This commit is contained in:
Дмитрий Левин 2016-12-24 17:35:40 +00:00
parent 9af28a4d13
commit a3c2e4e20b
5 changed files with 87 additions and 16 deletions

1
tests/.gitignore vendored
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@ -223,6 +223,7 @@ preadv
preadv-pwritev
preadv2-pwritev2
print_maxfd
printstr
prlimit64
process_vm_readv
process_vm_writev

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@ -283,6 +283,7 @@ check_PROGRAMS = \
preadv-pwritev \
preadv2-pwritev2 \
print_maxfd \
printstr \
prlimit64 \
process_vm_readv \
process_vm_writev \
@ -667,6 +668,7 @@ DECODER_TESTS = \
preadv-pwritev.test \
preadv2-pwritev2.test \
preadv.test \
printstr.test \
prlimit64.test \
process_vm_readv.test \
process_vm_writev.test \

69
tests/printstr.c Normal file
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@ -0,0 +1,69 @@
/*
* Check decoding of non-NUL-terminated strings when len == -1.
*
* Copyright (c) 2016 Dmitry V. Levin <ldv@altlinux.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "tests.h"
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/uio.h>
#define DEFAULT_STRLEN 32
int
main(void)
{
char *const buf = tail_alloc(DEFAULT_STRLEN + 1);
const struct iovec io = {
.iov_base = buf,
.iov_len = -1
};
int rc;
buf[0] = 0;
tprintf("%s", "");
memset(buf + 1, 'X', DEFAULT_STRLEN);
buf[DEFAULT_STRLEN - 1] = 0;
rc = writev(-1, &io, 1);
tprintf("writev(-1, [{iov_base=\"\\0%*s\\0\"..., iov_len=%lu}], 1)"
" = %s\n", DEFAULT_STRLEN - 2, buf + 1, -1UL, sprintrc(rc));
buf[DEFAULT_STRLEN - 1] = 'X';
buf[DEFAULT_STRLEN] = 0;
rc = writev(-1, &io, 1);
tprintf("writev(-1, [{iov_base=\"\\0%*s\"..., iov_len=%lu}], 1)"
" = %s\n", DEFAULT_STRLEN - 1, buf + 1, -1UL, sprintrc(rc));
tprintf("+++ exited with 0 +++\n");
return 0;
}

6
tests/printstr.test Executable file
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@ -0,0 +1,6 @@
#!/bin/sh
# Check decoding of non-NUL-terminated strings when len == -1.
. "${srcdir=.}/init.sh"
run_strace_match_diff -e trace=writev

25
util.c
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@ -850,12 +850,11 @@ printpath(struct tcb *const tcp, const kernel_ureg_t addr)
/*
* Print string specified by address `addr' and length `len'.
* If `len' == -1, set QUOTE_0_TERMINATED bit in `user_style'.
* If `user_style' has QUOTE_0_TERMINATED bit set, treat the string
* as a NUL-terminated string.
* Pass `user_style' on to `string_quote'.
* Append `...' to the output if either the string length exceeds `max_strlen',
* or `len' != -1 and the string length exceeds `len'.
* or QUOTE_0_TERMINATED bit is set and the string length exceeds `len'.
*/
void
printstr_ex(struct tcb *const tcp, const kernel_ureg_t addr, const long len,
@ -882,22 +881,16 @@ printstr_ex(struct tcb *const tcp, const kernel_ureg_t addr, const long len,
outstr = xmalloc(outstr_size);
}
/* Fetch one byte more because string_quote may look one byte ahead. */
size = max_strlen + 1;
if (len == -1) {
/*
* Treat as a NUL-terminated string: fetch one byte more
* because string_quote may look one byte ahead.
*/
style |= QUOTE_0_TERMINATED;
if (size > (unsigned long) len)
size = (unsigned long) len;
if (style & QUOTE_0_TERMINATED)
rc = umovestr(tcp, addr, size, str);
} else {
if (size > (unsigned long) len)
size = (unsigned long) len;
if (style & QUOTE_0_TERMINATED)
rc = umovestr(tcp, addr, size, str);
else
rc = umoven(tcp, addr, size, str);
}
else
rc = umoven(tcp, addr, size, str);
if (rc < 0) {
printaddr(addr);
return;