From: Eric Biggers <ebiggers@kernel.org>
To: Arnd Bergmann <arnd@arndb.de>, Al Viro <viro@zeniv.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>,
bpf@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-ppp@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot <syzbot+eb853b51b10f1befa0b7@syzkaller.appspotmail.com>,
syzkaller-bugs@googlegroups.com
Subject: [PATCH] ppp: fix out-of-bounds access in bpf_prog_create()
Date: Wed, 4 Dec 2019 21:54:19 -0800 [thread overview]
Message-ID: <20191205055419.13435-1-ebiggers@kernel.org> (raw)
In-Reply-To: <20191205052220.GC1158@sol.localdomain>
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>
---
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
next prev parent reply other threads:[~2019-12-05 5:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-17 18:49 KASAN: slab-out-of-bounds Read in bpf_prog_create syzbot
2019-09-28 3:15 ` Eric Biggers
2019-12-05 5:22 ` Eric Biggers
2019-12-05 5:54 ` Eric Biggers [this message]
2019-12-05 9:07 ` [PATCH] ppp: fix out-of-bounds access in bpf_prog_create() Arnd Bergmann
2019-12-05 22:45 ` David Miller
2019-12-05 9:08 ` KASAN: slab-out-of-bounds Read in bpf_prog_create Arnd Bergmann
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