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Fix integer overflow detection in dd

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dd(1) tried to detect whether the seek offset would overflow, but it failed
to account for the case where the provided argument was negative and the
file was a regular file (negative seeks are allowed for character devices).
I fixed it, and added a regression test.

Reported by:	Coverity
CID:		1368659
MFC after:	3 weeks
Sponsored by:	Spectra Logic Corp
This commit is contained in:
Alan Somers 2017-05-31 16:07:32 +00:00
parent dff36e69a1
commit af2b6af393
3 changed files with 56 additions and 1 deletions
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2
bin/dd/position.c
View File

@ -70,7 +70,7 @@ seek_offset(IO *io)
*
* Bail out if the calculation of a file offset would overflow.
*/
if ((io->flags & ISCHR) == 0 && n > OFF_MAX / (ssize_t)sz)
if ((io->flags & ISCHR) == 0 && (n < 0 || n > OFF_MAX / (ssize_t)sz))
errx(1, "seek offsets cannot be larger than %jd",
(intmax_t)OFF_MAX);
else if ((io->flags & ISCHR) != 0 && (uint64_t)n > UINT64_MAX / sz)

5
bin/dd/tests/Makefile
View File

@ -1,5 +1,10 @@
# $FreeBSD$
.include <src.opts.mk>
.PATH: ${.CURDIR}/..
ATF_TESTS_SH= dd2_test
NETBSD_ATF_TESTS_SH= dd_test
.include <netbsd-tests.test.mk>

50
bin/dd/tests/dd2_test.sh Executable file
View File

@ -0,0 +1,50 @@
#
# Copyright (c) 2017 Spectra Logic Corporation
# 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.
#
# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
# ``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 FOUNDATION OR CONTRIBUTORS
# 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.
#
# $FreeBSD$
atf_test_case seek_overflow
seek_overflow_head() {
atf_set "descr" "dd(1) should reject too-large seek values"
}
seek_overflow_body() {
touch f.in
# Positive tests
seek=`echo "2^63 / 4096 - 1" | bc`
atf_check -s exit:0 -e ignore dd if=f.in of=f.out bs=4096 seek=$seek
# Negative tests
seek=`echo "2^63 / 4096" | bc`
atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
dd if=f.in of=f.out bs=4096 seek=$seek
atf_check -s not-exit:0 -e match:"seek offsets cannot be larger than" \
dd if=f.in of=f.out bs=4096 seek=-1
}
atf_init_test_cases()
{
atf_add_test_case seek_overflow
}