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Mon, 31 Aug 2026 06:42:21 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=dell.com; i=@dell.com; q=dns/txt; s=smtpdev1; t=1788172941; x=1819708941; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=5gkr5NO3n5A3qTG42DpHm3dTr1ODWlNH3Mf6fRH6yzo=; b=cE2eXIr/Ix5kgJC/9O+Ice9wLt6gOhPmaQS+voRGuhd7wWYwZMdiVFzd f1sY0YekfQ4trvUiX7L8tlaotwEASkiAaYUyVbeAttmITyJ2UmrFplv1s l77PclKQSGVbcKct7S290ppEAmiMb5UJ23agg6q/RhLGRKmpgXw79PUr5 aRVriD8y/osjCF4ZXqPcr4wJFAK9VfvPZUli0RMiYaoh1RjPDkfTHccwb mYJTyVydBqG8vPtlAmzBNW1j97/bWFKdElqYGzVjIJpPMK68jA6XFnRtq On/EMniObmTQ304Kbt7XQoAVEBEl/nh3h4Evh6+K63khL88llM4WAhb8F w==; X-CSE-ConnectionGUID: yxym3LyCTGGi1XBf/IBN5Q== X-CSE-MsgGUID: ySwVzOFgS+yoUKA1WlOpYQ== X-LoopCount0: from 10.94.8.206 X-MS-Exchange-CrossPremises-AuthAs: Internal Received: from w-96j1th4.apac.dell.com (HELO W-96J1TH4.blr.amer.dell.com) ([10.94.8.206]) by esapsmtplv05.us.dell.com with ESMTP/TLS/TLS_AES_256_GCM_SHA384; 31 Aug 2026 10:42:20 +0000 From: Prabhakar Pujeri To: linux-nfs@vger.kernel.org Cc: Prabhakar Pujeri Subject: [PATCH 3/3] gssd: reject server hostnames that do not fit Date: Mon, 31 Aug 2026 10:42:11 +0000 Message-ID: <20260831104211.2297-4-prabhakar.pujeri@dell.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831104211.2297-1-prabhakar.pujeri@dell.com> References: <20260831104211.2297-1-prabhakar.pujeri@dell.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-31_03,2026-08-27_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 adultscore=0 malwarescore=0 bulkscore=0 clxscore=1015 impostorscore=0 suspectscore=0 lowpriorityscore=0 priorityscore=1501 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608310091 X-Authority-Analysis: v=2.4 cv=BdToFLt2 c=1 sm=1 tr=0 ts=6a955a8e cx=c_pps a=Z2e5DKjA+8LiMDv5v6mwwA==:117 a=t4Iba6VQkoKuxR139xjPXA==:17 a=Sv0fKeRqtYgA:10 a=ke5jqHz-1hQA:10 a=VkNPw1HP01LnGYTKEx00:22 a=6gNNCFAoQcIphELLPWWu:22 a=sEWawkeXllE7TocFc0N_:22 a=iLNU1ar6AAAA:8 a=XvIGpVyiO-i08diihGsA:9 a=hlJyneSgMmFPbskH-t2w:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODMxMDA5MiBTYWx0ZWRfX7jxg1jieaYTR wn3olSHgo55NmpOPQYsIRsBPbk8wtG4jb41LS/DleSveAcCOU68/hw7BEK84RmoV2eZYVb7QzJ8 cKfBYsc413u4JBvw6FC1elVQafKhPmLAbOEyGZ4NP06uPOC2UhLbNM6407PmzUFHdOWdBjOWltB uHTQwZTjeCYSALMJbJqxgMZaun1ump8pSF8MlYm6Xp0ZMafCxipw5i+k0ePnKw59eO7CzAUuILz qo2x6CCIIfCEkVOJ2Vw+eBI0HBQ9dbKCEjSXTgtzATo9SjFg2T0nJK34DOvtOko/Qf4pRYKvfBb Lb4pz7322as8hfIco2KOCzW7uae4fZBmCRD1pTk69l4BIXMmGXYX2kyjJuGsYf6FVuUT/L8uwqK zGFazYOOY35VVum+XWwOEc6gvmm/Plwy6f43k/vbd+KATIwAJyZtuj0sbs56Fy2ZsLvVmjKu77L Sz288C4imBU+HpN9mYw== X-Proofpoint-Spam-Info: AW1haW4tMjYwODMxMDA5MiBTYWx0ZWRfXzJZ74M6VwOs6 oOa5MLOUiHZaWeEz6KV1JnqFDriL982I9ksXO4VsL642kr2rNrjufet2FL4HVxb+oIFRwfvny0D UIXSGzDdiVShpnPyfk1+QlMJJ9XN0t8= X-Proofpoint-GUID: hl83hYYabO6DciGaxiB6zsrzGgDNrqLb X-Proofpoint-ORIG-GUID: hl83hYYabO6DciGaxiB6zsrzGgDNrqLb X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 impostorscore=0 priorityscore=1501 adultscore=0 phishscore=0 spamscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608310092 find_keytab_entry() copies a hostname from the kernel upcall into a fixed NI_MAXHOST buffer with strcpy(), allowing an overlong name to overwrite the stack. Use snprintf() and check its result. Reject a truncated hostname with ENAMETOOLONG instead of performing a keytab lookup with a different name. The verified string also fits in the following myhostad copy. Signed-off-by: Prabhakar Pujeri --- utils/gssd/krb5_util.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/utils/gssd/krb5_util.c b/utils/gssd/krb5_util.c index bc063a8b..7ad67131 100644 --- a/utils/gssd/krb5_util.c +++ b/utils/gssd/krb5_util.c @@ -841,8 +841,13 @@ find_keytab_entry(krb5_context context, krb5_keytab kt, /* Get full local hostname */ if (srchost) { - strcpy(myhostname, srchost); - strcpy(myhostad, myhostname); + retval = snprintf(myhostname, sizeof(myhostname), "%s", srchost); + if (retval < 0 || (size_t)retval >= sizeof(myhostname)) { + retval = ENAMETOOLONG; + printerr(1, "source hostname is too long\n"); + goto out; + } + strcpy(myhostad, myhostname); } else { /* Borrow myhostad for gethostname(), we need it later anyways */ if (gethostname(myhostad, sizeof(myhostad)-1) == -1) { -- 2.55.0