From: Dan Carpenter <dan.carpenter@oracle.com>
To: Colin King <colin.king@canonical.com>
Cc: Matthew Garrett <mjg59@google.com>,
Mimi Zohar <zohar@linux.vnet.ibm.com>,
James Morris <jmorris@namei.org>,
"Serge E . Hallyn" <serge@hallyn.com>,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] EVM: Fix null dereference on xattr when xattr fails to allocate
Date: Tue, 29 May 2018 12:05:04 +0300 [thread overview]
Message-ID: <20180529090504.6dpdadjyjxo45nu2@mwanda> (raw)
In-Reply-To: <20180527225510.25612-1-colin.king@canonical.com>
Not really related to this patch except I was looking at the function:
security/integrity/evm/evm_secfs.c
191 ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_INTEGRITY_EVM_XATTR);
192 if (IS_ERR(ab))
193 return PTR_ERR(ab);
194
195 xattr = kmalloc(sizeof(struct xattr_list), GFP_KERNEL);
196 if (!xattr) {
197 err = -ENOMEM;
198 goto out;
199 }
200
201 xattr->name = memdup_user_nul(buf, count);
202 if (IS_ERR(xattr->name)) {
203 err = PTR_ERR(xattr->name);
204 xattr->name = NULL;
205 goto out;
206 }
207
208 /* Remove any trailing newline */
209 len = strlen(xattr->name);
210 if (xattr->name[len-1] == '\n')
strlen() could be zero, leading to a read underflow here.
211 xattr->name[len-1] = '\0';
212
213 if (strcmp(xattr->name, ".") == 0) {
214 evm_xattrs_locked = 1;
215 newattrs.ia_mode = S_IFREG | 0440;
216 newattrs.ia_valid = ATTR_MODE;
217 inode = evm_xattrs->d_inode;
218 inode_lock(inode);
219 err = simple_setattr(evm_xattrs, &newattrs);
220 inode_unlock(inode);
221 audit_log_format(ab, "locked");
222 if (!err)
223 err = count;
224 goto out;
225 }
regards,
dan carpenter
next prev parent reply other threads:[~2018-05-29 9:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-27 22:55 [PATCH] EVM: Fix null dereference on xattr when xattr fails to allocate Colin King
2018-05-29 9:05 ` Dan Carpenter [this message]
2018-05-29 12:31 ` Mimi Zohar
2018-05-29 13:11 ` [PATCH] EVM: prevent array underflow in evm_write_xattrs() Dan Carpenter
2018-05-31 15:00 ` Mimi Zohar
2018-05-29 12:30 ` [PATCH] EVM: Fix null dereference on xattr when xattr fails to allocate Mimi Zohar
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