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| author | Anmol Karn <anmol.karan123@gmail.com> | 2020-11-20 00:40:43 +0530 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-20 10:04:58 -0800 |
| commit | 3b3fd068c56e3fbea30090859216a368398e39bf (patch) | |
| tree | a2d71d8f0ad6a657e6cf7b049adae7df9f19f5e1 /net | |
| parent | f46e79aa1a2bea7de2885fa8d79a68d11545a5fd (diff) | |
| download | linux-3b3fd068c56e3fbea30090859216a368398e39bf.tar.bz2 | |
rose: Fix Null pointer dereference in rose_send_frame()
rose_send_frame() dereferences `neigh->dev` when called from
rose_transmit_clear_request(), and the first occurrence of the
`neigh` is in rose_loopback_timer() as `rose_loopback_neigh`,
and it is initialized in rose_add_loopback_neigh() as NULL.
i.e when `rose_loopback_neigh` used in rose_loopback_timer()
its `->dev` was still NULL and rose_loopback_timer() was calling
rose_rx_call_request() without checking for NULL.
- net/rose/rose_link.c
This bug seems to get triggered in this line:
rose_call = (ax25_address *)neigh->dev->dev_addr;
Fix it by adding NULL checking for `rose_loopback_neigh->dev`
in rose_loopback_timer().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Reported-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com
Tested-by: syzbot+a1c743815982d9496393@syzkaller.appspotmail.com
Link: https://syzkaller.appspot.com/bug?id=9d2a7ca8c7f2e4b682c97578dfa3f236258300b3
Signed-off-by: Anmol Karn <anmol.karan123@gmail.com>
Link: https://lore.kernel.org/r/20201119191043.28813-1-anmol.karan123@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/rose/rose_loopback.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/net/rose/rose_loopback.c b/net/rose/rose_loopback.c index 7b094275ea8b..11c45c8c6c16 100644 --- a/net/rose/rose_loopback.c +++ b/net/rose/rose_loopback.c @@ -96,10 +96,19 @@ static void rose_loopback_timer(struct timer_list *unused) } if (frametype == ROSE_CALL_REQUEST) { - if ((dev = rose_dev_get(dest)) != NULL) { - if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) - kfree_skb(skb); - } else { + if (!rose_loopback_neigh->dev) { + kfree_skb(skb); + continue; + } + + dev = rose_dev_get(dest); + if (!dev) { + kfree_skb(skb); + continue; + } + + if (rose_rx_call_request(skb, dev, rose_loopback_neigh, lci_o) == 0) { + dev_put(dev); kfree_skb(skb); } } else { |