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net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour

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Commit db31c55a6f (net: clamp ->msg_namelen instead of returning an
error) introduced the clamping of msg_namelen when the unsigned value
was larger than sizeof(struct sockaddr_storage). This caused a
msg_namelen of -1 to be valid. The native code was subsequently fixed by
commit dbb490b965 (net: socket: error on a negative msg_namelen).

In addition, the native code sets msg_namelen to 0 when msg_name is
NULL. This was done in commit (6a2a2b3ae0 net:socket: set msg_namelen
to 0 if msg_name is passed as NULL in msghdr struct from userland) and
subsequently updated by 08adb7dabd (fold verify_iovec() into
copy_msghdr_from_user()).

This patch brings the get_compat_msghdr() in line with
copy_msghdr_from_user().

Fixes: db31c55a6f (net: clamp ->msg_namelen instead of returning an error)
Cc: David S. Miller <davem@davemloft.net>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Catalin Marinas 2015-03-20 16:48:13 +00:00 committed by David S. Miller
parent de58a6da85
commit 91edd096e2
1 changed files with 7 additions and 0 deletions
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7
net/compat.c
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@ -49,6 +49,13 @@ ssize_t get_compat_msghdr(struct msghdr *kmsg,
__get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||
__get_user(kmsg->msg_flags, &umsg->msg_flags))
return -EFAULT;
if (!uaddr)
kmsg->msg_namelen = 0;
if (kmsg->msg_namelen < 0)
return -EINVAL;
if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
kmsg->msg_namelen = sizeof(struct sockaddr_storage);
kmsg->msg_control = compat_ptr(tmp3);