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b=gKa+gBURlg+yxzkWSpogfSDOLHJNfNgWMUr+4R3UpZ7GHzR4qdQbp6jRgNfGrq34CzNobt HnLbroPhglZeqswB08q7u7rjkM2qA1y+VEMLvvCM2snic/Ac+U1/L/TN0XYnW9pMzlSm3p 8sGjjEfdy7yWTsU38x34Djf8te5u41U= X-MC-Unique: Hshe4TSYPuKM03AE4S-j8Q-1 From: Eric Blake To: qemu-devel@nongnu.org Subject: [PATCH] nbd: Avoid off-by-one in long export name truncation Date: Mon, 22 Jun 2020 16:03:55 -0500 Message-Id: <20200622210355.414941-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=205.139.110.120; envelope-from=eblake@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/06/22 01:27:42 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , vsementsov@virtuozzo.com, "open list:Network Block Dev..." , Max Reitz Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" When snprintf returns the same value as the buffer size, the final byte was truncated to ensure a NUL terminator. Fortunately, such long export names are unusual enough, with no real impact other than what is displayed to the user. Fixes: 5c86bdf12089 Reported-by: Max Reitz Signed-off-by: Eric Blake Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/nbd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/nbd.c b/block/nbd.c index eed160c5cda1..8301fcac0589 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -2009,7 +2009,7 @@ static void nbd_refresh_filename(BlockDriverState *bs) len =3D snprintf(bs->exact_filename, sizeof(bs->exact_filename), "nbd://%s:%s", host, port); } - if (len > sizeof(bs->exact_filename)) { + if (len >=3D sizeof(bs->exact_filename)) { /* Name is too long to represent exactly, so leave it empty. */ bs->exact_filename[0] =3D '\0'; } --=20 2.27.0