From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Biggers Date: Thu, 05 Dec 2019 05:54:19 +0000 Subject: [PATCH] ppp: fix out-of-bounds access in bpf_prog_create() Message-Id: <20191205055419.13435-1-ebiggers@kernel.org> List-Id: References: <20191205052220.GC1158@sol.localdomain> In-Reply-To: <20191205052220.GC1158@sol.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Arnd Bergmann , Al Viro Cc: Paul Mackerras , bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, syzbot , syzkaller-bugs@googlegroups.com From: Eric Biggers sock_fprog_kern::len is in units of struct sock_filter, not bytes. Fixes: 3e859adf3643 ("compat_ioctl: unify copy-in of ppp filters") Reported-by: syzbot+eb853b51b10f1befa0b7@syzkaller.appspotmail.com Signed-off-by: Eric Biggers --- drivers/net/ppp/ppp_generic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 0cb1c2d0a8bc..3bf8a8b42983 100644 --- a/drivers/net/ppp/ppp_generic.c +++ b/drivers/net/ppp/ppp_generic.c @@ -564,8 +564,9 @@ static struct bpf_prog *get_filter(struct sock_fprog *uprog) return NULL; /* uprog->len is unsigned short, so no overflow here */ - fprog.len = uprog->len * sizeof(struct sock_filter); - fprog.filter = memdup_user(uprog->filter, fprog.len); + fprog.len = uprog->len; + fprog.filter = memdup_user(uprog->filter, + uprog->len * sizeof(struct sock_filter)); if (IS_ERR(fprog.filter)) return ERR_CAST(fprog.filter); -- 2.24.0