From e424b6550f486b2a9ab32b13c3824021199bac54 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Golembiovsk=C3=BD?= Date: Wed, 5 Oct 2016 23:40:20 +0200 Subject: [PATCH] qemu-nbd: Shrink image size by specified offset MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When --offset is set the apparent device size has to be adjusted accordingly. Otherwise client may request read/write beyond the file end which would fail. Signed-off-by: Tomáš Golembiovský Message-Id: <8a31654cb182932db78b95aae1e904fc2bd1c465.1475698895.git.tgolembi@redhat.com> Reviewed-by: Eric Blake Signed-off-by: Paolo Bonzini --- qemu-nbd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/qemu-nbd.c b/qemu-nbd.c index 99297a556f..705b95ec29 100644 --- a/qemu-nbd.c +++ b/qemu-nbd.c @@ -901,6 +901,14 @@ int main(int argc, char **argv) exit(EXIT_FAILURE); } + if (dev_offset >= fd_size) { + error_report("Offset (%lld) has to be smaller than the image size " + "(%lld)", + (long long int)dev_offset, (long long int)fd_size); + exit(EXIT_FAILURE); + } + fd_size -= dev_offset; + if (partition != -1) { ret = find_partition(blk, partition, &dev_offset, &fd_size); if (ret < 0) {