From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Date: Tue, 10 Apr 2018 09:42:50 -0500 Subject: KASAN: null-ptr-deref Read in xattr_getsecurity In-Reply-To: <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> (Tetsuo Handa's message of "Tue, 10 Apr 2018 19:13:23 +0900") References: <0000000000008d2e0d05697a693d@google.com> <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> Message-ID: <87o9irw2ad.fsf@xmission.com> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org Tetsuo Handa writes: > From 904d07a6eb014f3df0c5a1ebfcfd4323276a9a76 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa > Date: Tue, 10 Apr 2018 15:15:16 +0900 > Subject: [PATCH] commoncap: Handle memory allocation failure. > > syzbot is reporting NULL pointer dereference at xattr_getsecurity() [1], > for cap_inode_getsecurity() is returning sizeof(struct vfs_cap_data) when > memory allocation failed. Return -ENOMEM if memory allocation failed. > > [1] https://syzkaller.appspot.com/bug?id=a55ba438506fe68649a5f50d2d82d56b365e0107 Acked-by: "Eric W. Biederman" Tetsuo I can pick this up, or do you have preferred path for getting this change merged? Serge does this fix look ok to you? I am a bit worried that might be a bit brittler but I don't see any issues with this change. Eric > Signed-off-by: Tetsuo Handa > Fixes: 8db6c34f1dbc8e06 ("Introduce v3 namespaced file capabilities") > Reported-by: syzbot > Cc: stable # 4.14+ > Cc: Serge E. Hallyn > Cc: Eric W. Biederman > --- > security/commoncap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 48620c9..1ce701f 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -449,6 +449,8 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, > magic |= VFS_CAP_FLAGS_EFFECTIVE; > memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); > cap->magic_etc = cpu_to_le32(magic); > + } else { > + size = -ENOMEM; > } > } > kfree(tmpbuf); > -- > 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out02.mta.xmission.com ([166.70.13.232]:44831 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097AbeDJOoV (ORCPT ); Tue, 10 Apr 2018 10:44:21 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: Tetsuo Handa Cc: syzbot , "Serge E. Hallyn" , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk, References: <0000000000008d2e0d05697a693d@google.com> <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> Date: Tue, 10 Apr 2018 09:42:50 -0500 In-Reply-To: <9d192497-8b1e-ca8d-0ed8-b3324ee1e361@I-love.SAKURA.ne.jp> (Tetsuo Handa's message of "Tue, 10 Apr 2018 19:13:23 +0900") Message-ID: <87o9irw2ad.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: KASAN: null-ptr-deref Read in xattr_getsecurity Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Tetsuo Handa writes: > From 904d07a6eb014f3df0c5a1ebfcfd4323276a9a76 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa > Date: Tue, 10 Apr 2018 15:15:16 +0900 > Subject: [PATCH] commoncap: Handle memory allocation failure. > > syzbot is reporting NULL pointer dereference at xattr_getsecurity() [1], > for cap_inode_getsecurity() is returning sizeof(struct vfs_cap_data) when > memory allocation failed. Return -ENOMEM if memory allocation failed. > > [1] https://syzkaller.appspot.com/bug?id=a55ba438506fe68649a5f50d2d82d56b365e0107 Acked-by: "Eric W. Biederman" Tetsuo I can pick this up, or do you have preferred path for getting this change merged? Serge does this fix look ok to you? I am a bit worried that might be a bit brittler but I don't see any issues with this change. Eric > Signed-off-by: Tetsuo Handa > Fixes: 8db6c34f1dbc8e06 ("Introduce v3 namespaced file capabilities") > Reported-by: syzbot > Cc: stable # 4.14+ > Cc: Serge E. Hallyn > Cc: Eric W. Biederman > --- > security/commoncap.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/security/commoncap.c b/security/commoncap.c > index 48620c9..1ce701f 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -449,6 +449,8 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, > magic |= VFS_CAP_FLAGS_EFFECTIVE; > memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); > cap->magic_etc = cpu_to_le32(magic); > + } else { > + size = -ENOMEM; > } > } > kfree(tmpbuf); > -- > 1.8.3.1