From patchwork Mon Apr 27 17:07:30 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. 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Wong" To: sandeen@sandeen.net Cc: Christoph Hellwig , linux-xfs@vger.kernel.org Subject: [PATCH] libxcmd: don't crash if el_gets returns null Message-ID: <20200427170730.GQ6742@magnolia> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9604 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 spamscore=0 bulkscore=0 suspectscore=1 mlxlogscore=999 phishscore=0 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004270139 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9604 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 spamscore=0 clxscore=1015 phishscore=0 mlxlogscore=999 adultscore=0 priorityscore=1501 mlxscore=0 suspectscore=1 malwarescore=0 lowpriorityscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004270139 Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Darrick J. Wong el_gets returns NULL if it fails to read any characters (due to EOF or errors occurred). strdup will crash if it is fed a NULL string, so check the return value to avoid segfaulting. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig --- libxcmd/input.c | 20 +++++++++++++------- 1 file changed, 13 insertions(+), 7 deletions(-) diff --git a/libxcmd/input.c b/libxcmd/input.c index 137856e3..a4548d7c 100644 --- a/libxcmd/input.c +++ b/libxcmd/input.c @@ -47,6 +47,7 @@ fetchline(void) static EditLine *el; static History *hist; HistEvent hevent; + const char *cmd; char *line; int count; @@ -59,13 +60,18 @@ fetchline(void) el_set(el, EL_PROMPT, el_get_prompt); el_set(el, EL_HIST, history, (const char *)hist); } - line = strdup(el_gets(el, &count)); - if (line) { - if (count > 0) - line[count-1] = '\0'; - if (*line) - history(hist, &hevent, H_ENTER, line); - } + cmd = el_gets(el, &count); + if (!cmd) + return NULL; + + line = strdup(cmd); + if (!line) + return NULL; + + if (count > 0) + line[count-1] = '\0'; + if (*line) + history(hist, &hevent, H_ENTER, line); return line; } #else