Revision 8754e1379e7089516a449821f88e1fe1ebbae5e1 authored by Xie He on 24 July 2020, 16:33:47 UTC, committed by David S. Miller on 25 July 2020, 03:17:42 UTC
This patch fixed 2 issues with the usage of skb_cow in LAPB drivers "lapbether" and "hdlc_x25": 1) After skb_cow fails, kfree_skb should be called to drop a reference to the skb. But in both drivers, kfree_skb is not called. 2) skb_cow should be called before skb_push so that is can ensure the safety of skb_push. But in "lapbether", it is incorrectly called after skb_push. More details about these 2 issues: 1) The behavior of calling kfree_skb on failure is also the behavior of netif_rx, which is called by this function with "return netif_rx(skb);". So this function should follow this behavior, too. 2) In "lapbether", skb_cow is called after skb_push. This results in 2 logical issues: a) skb_push is not protected by skb_cow; b) An extra headroom of 1 byte is ensured after skb_push. This extra headroom has no use in this function. It also has no use in the upper-layer function that this function passes the skb to (x25_lapb_receive_frame in net/x25/x25_dev.c). So logically skb_cow should instead be called before skb_push. Cc: Eric Dumazet <edumazet@google.com> Cc: Martin Schiller <ms@dev.tdt.de> Signed-off-by: Xie He <xie.he.0141@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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File | Mode | Size |
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apparmor | ||
bpf | ||
integrity | ||
keys | ||
loadpin | ||
lockdown | ||
safesetid | ||
selinux | ||
smack | ||
tomoyo | ||
yama | ||
Kconfig | -rw-r--r-- | 10.7 KB |
Kconfig.hardening | -rw-r--r-- | 7.9 KB |
Makefile | -rw-r--r-- | 1.3 KB |
commoncap.c | -rw-r--r-- | 39.0 KB |
device_cgroup.c | -rw-r--r-- | 21.1 KB |
inode.c | -rw-r--r-- | 10.6 KB |
lsm_audit.c | -rw-r--r-- | 10.7 KB |
min_addr.c | -rw-r--r-- | 1.3 KB |
security.c | -rw-r--r-- | 63.3 KB |
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