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X-IronPort-AV: E=Sophos;i="5.47,409,1515427200"; d="scan'208";a="73257828" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 02 Mar 2018 03:29:36 +0800 Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP; 01 Mar 2018 11:22:59 -0800 Received: from thinkpad-bart.sdcorp.global.sandisk.com (HELO thinkpad-bart.int.fusionio.com) ([10.11.171.236]) by uls-op-cesaip01.wdc.com with ESMTP; 01 Mar 2018 11:29:36 -0800 From: Bart Van Assche To: Christophe Varoqui Date: Thu, 1 Mar 2018 11:29:33 -0800 Message-Id: <20180301192935.14643-5-bart.vanassche@wdc.com> In-Reply-To: <20180301192935.14643-1-bart.vanassche@wdc.com> References: <20180301192935.14643-1-bart.vanassche@wdc.com> X-Greylist: Sender passed SPF test, Sender IP whitelisted by DNSRBL, ACL 207 matched, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 01 Mar 2018 19:30:35 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 01 Mar 2018 19:30:35 +0000 (UTC) for IP:'216.71.153.141' DOMAIN:'esa3.hgst.iphmx.com' HELO:'esa3.hgst.iphmx.com' FROM:'bart.vanassche@wdc.com' RCPT:'' X-RedHat-Spam-Score: -0.8 (DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_LOW) 216.71.153.141 esa3.hgst.iphmx.com 216.71.153.141 esa3.hgst.iphmx.com X-Scanned-By: MIMEDefang 2.78 on 10.5.110.29 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-loop: dm-devel@redhat.com Cc: Bart Van Assche , dm-devel@redhat.com Subject: [dm-devel] [PATCH 4/6] kpartx: Improve reliability of find_loop_by_file() X-BeenThere: dm-devel@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: device-mapper development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Thu, 01 Mar 2018 19:30:54 +0000 (UTC) X-Virus-Scanned: ClamAV using ClamSMTP Avoid that the strchr() call in this function examines uninitialized data on the stack. This patch avoids that Coverity reports the following: CID 173252: Error handling issues (CHECKED_RETURN) "read(int, void *, size_t)" returns the number of bytes read, but it is ignored. Signed-off-by: Bart Van Assche Reviewed-by: Martin Wilck --- kpartx/lopart.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/kpartx/lopart.c b/kpartx/lopart.c index 02b29e8cf91d..69c1eda1cc5c 100644 --- a/kpartx/lopart.c +++ b/kpartx/lopart.c @@ -64,7 +64,7 @@ char *find_loop_by_file(const char *filename) DIR *dir; struct dirent *dent; char dev[64], *found = NULL, *p; - int fd; + int fd, bytes_read; struct stat statbuf; struct loop_info loopinfo; const char VIRT_BLOCK[] = "/sys/devices/virtual/block"; @@ -86,14 +86,15 @@ char *find_loop_by_file(const char *filename) if (fd < 0) continue; - if (read(fd, dev, sizeof(dev)) <= 0) { + bytes_read = read(fd, dev, sizeof(dev) - 1); + if (bytes_read <= 0) { close(fd); continue; } close(fd); - dev[sizeof(dev)-1] = '\0'; + dev[bytes_read] = '\0'; p = strchr(dev, '\n'); if (p != NULL) *p = '\0';