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Wed, 11 Aug 2021 14:52:02 +0000 (GMT) Received: from b06wcsmtp001.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id B6DBDA405C; Wed, 11 Aug 2021 14:52:01 +0000 (GMT) Received: from li-f45666cc-3089-11b2-a85c-c57d1a57929f.ibm.com (unknown [9.160.27.84]) by b06wcsmtp001.portsmouth.uk.ibm.com (Postfix) with ESMTP; Wed, 11 Aug 2021 14:52:01 +0000 (GMT) Message-ID: Subject: Re: [PATCH ima-evm-utils] evmctl: fix memory leak in get_password From: Mimi Zohar To: Bruno Meneguele , vt@altlinux.org Cc: linux-integrity@vger.kernel.org Date: Wed, 11 Aug 2021 10:52:00 -0400 In-Reply-To: <20210810202852.236354-1-bmeneg@redhat.com> References: <20210810202852.236354-1-bmeneg@redhat.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.28.5 (3.28.5-16.el8) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: jAQg5lmJz0cbiUQee5t9wv7qvvS9lhXo X-Proofpoint-GUID: flKxSt5oQpIRqc-Pu8Q8IEvJNX-ZSo9i X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-08-11_05:2021-08-11,2021-08-11 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 impostorscore=0 phishscore=0 malwarescore=0 adultscore=0 suspectscore=0 lowpriorityscore=0 spamscore=0 mlxlogscore=999 clxscore=1015 bulkscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2107140000 definitions=main-2108110098 Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org Hi Bruno, On Tue, 2021-08-10 at 17:28 -0300, Bruno Meneguele wrote: > The variable "password" is not freed nor returned in case get_password() > succeeds. Instead of using an intermediary variable ("pwd") for returning > the value, use the same "password" var. Issue found by Coverity scan tool. > > src/evmctl.c:2565: leaked_storage: Variable "password" going out of scope > leaks the storage it points to. > > Signed-off-by: Bruno Meneguele > --- > src/evmctl.c | 15 ++++++++++++--- > 1 file changed, 12 insertions(+), 3 deletions(-) > > diff --git a/src/evmctl.c b/src/evmctl.c > index 7a6f2021aa92..b49c7910a4a7 100644 > --- a/src/evmctl.c > +++ b/src/evmctl.c > @@ -2601,8 +2601,9 @@ static struct option opts[] = { > static char *get_password(void) > { > struct termios flags, tmp_flags; > - char *password, *pwd; > + char *password; > int passlen = 64; > + bool err = false; > > password = malloc(passlen); > if (!password) { > @@ -2622,16 +2623,24 @@ static char *get_password(void) > } > > printf("PEM password: "); > - pwd = fgets(password, passlen, stdin); > + if (fgets(password, passlen, stdin) == NULL) { > + perror("fgets"); > + /* we still need to restore the terminal */ > + err = true; > + } >From the fgets manpage: fgets() returns s on success, and NULL on error or when end of file occurs while no characters have been read. > /* restore terminal */ > if (tcsetattr(fileno(stdin), TCSANOW, &flags) != 0) { > perror("tcsetattr"); > + err = true; > + } > + > + if (err) { > free(password); > return NULL; > } > > - return pwd; > + return password; Wouldn't a simpler fix be to test "pwd" here? if (!pwd) free(password); return pwd; thanks, Mimi > } > > int main(int argc, char *argv[])