aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2019-05-29 22:36:10 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-06-04 05:59:41 (GMT)
commitd46ed35e51d206a20664b2f7beeb3eab9fd851b8 (patch)
treed9538d70b59bbafc53f738c4de2d2a1fd73d56ba
parent06411db92f8665e8ae8d45d3ebbf23b51c101952 (diff)
downloadkernel_replicant_linux-d46ed35e51d206a20664b2f7beeb3eab9fd851b8.zip
kernel_replicant_linux-d46ed35e51d206a20664b2f7beeb3eab9fd851b8.tar.gz
kernel_replicant_linux-d46ed35e51d206a20664b2f7beeb3eab9fd851b8.tar.bz2
net-gro: fix use-after-free read in napi_gro_frags()
[ Upstream commit a4270d6795b0580287453ea55974d948393e66ef ] If a network driver provides to napi_gro_frags() an skb with a page fragment of exactly 14 bytes, the call to gro_pull_from_frag0() will 'consume' the fragment by calling skb_frag_unref(skb, 0), and the page might be freed and reused. Reading eth->h_proto at the end of napi_frags_skb() might read mangled data, or crash under specific debugging features. BUG: KASAN: use-after-free in napi_frags_skb net/core/dev.c:5833 [inline] BUG: KASAN: use-after-free in napi_gro_frags+0xc6f/0xd10 net/core/dev.c:5841 Read of size 2 at addr ffff88809366840c by task syz-executor599/8957 CPU: 1 PID: 8957 Comm: syz-executor599 Not tainted 5.2.0-rc1+ #32 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x172/0x1f0 lib/dump_stack.c:113 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317 kasan_report+0x12/0x20 mm/kasan/common.c:614 __asan_report_load_n_noabort+0xf/0x20 mm/kasan/generic_report.c:142 napi_frags_skb net/core/dev.c:5833 [inline] napi_gro_frags+0xc6f/0xd10 net/core/dev.c:5841 tun_get_user+0x2f3c/0x3ff0 drivers/net/tun.c:1991 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2037 call_write_iter include/linux/fs.h:1872 [inline] do_iter_readv_writev+0x5f8/0x8f0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x184/0x610 fs/read_write.c:951 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1015 do_writev+0x15b/0x330 fs/read_write.c:1058 Fixes: a50e233c50db ("net-gro: restore frag0 optimization") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/core/dev.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/dev.c b/net/core/dev.c
index 255f99c..c6b2f6d 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -5804,7 +5804,6 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
skb_reset_mac_header(skb);
skb_gro_reset_offset(skb);
- eth = skb_gro_header_fast(skb, 0);
if (unlikely(skb_gro_header_hard(skb, hlen))) {
eth = skb_gro_header_slow(skb, hlen, 0);
if (unlikely(!eth)) {
@@ -5814,6 +5813,7 @@ static struct sk_buff *napi_frags_skb(struct napi_struct *napi)
return NULL;
}
} else {
+ eth = (const struct ethhdr *)skb->data;
gro_pull_from_frag0(skb, hlen);
NAPI_GRO_CB(skb)->frag0 += hlen;
NAPI_GRO_CB(skb)->frag0_len -= hlen;