From: Eric Biggers Date: Thu, 5 Dec 2019 05:54:19 +0000 (-0800) Subject: ppp: fix out-of-bounds access in bpf_prog_create() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=0033b34a03ec5cf747cdaf9b1f9dceb91c020f17;p=linux.git ppp: fix out-of-bounds access in bpf_prog_create() 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 Reviewed-by: Arnd Bergmann Signed-off-by: David S. Miller --- diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c index 0cb1c2d0a8bcb..3bf8a8b429830 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);