Message ID | 20191205055419.13435-1-ebiggers@kernel.org (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | ppp: fix out-of-bounds access in bpf_prog_create() | expand |
On Thu, Dec 5, 2019 at 6:55 AM Eric Biggers <ebiggers@kernel.org> wrote: > > From: Eric Biggers <ebiggers@google.com> > > 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 <ebiggers@google.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Thanks for fixing the bug I introduced!
From: Eric Biggers <ebiggers@kernel.org> Date: Wed, 4 Dec 2019 21:54:19 -0800 > From: Eric Biggers <ebiggers@google.com> > > 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 <ebiggers@google.com> Applied, thank you.
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);