| From | Luis Henriques <> | Subject | [PATCH 3.16.y-ckt 164/165] net: compat: Update get_compat_msghdr() to match copy_msghdr_from_user() behaviour | Date | Wed, 25 Mar 2015 14:02:17 +0000 |
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3.16.7-ckt9 -stable review patch. If anyone has any objections, please let me know.
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From: Catalin Marinas <catalin.marinas@arm.com>
commit 91edd096e224941131f896b86838b1e59553696a upstream.
Commit db31c55a6fb2 (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 dbb490b96584 (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 (6a2a2b3ae075 net:socket: set msg_namelen to 0 if msg_name is passed as NULL in msghdr struct from userland) and subsequently updated by 08adb7dabd48 (fold verify_iovec() into copy_msghdr_from_user()).
This patch brings the get_compat_msghdr() in line with copy_msghdr_from_user().
Fixes: db31c55a6fb2 (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> [ luis: backported to 3.16: used davem's backport to 3.14 ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- net/compat.c | 7 +++++++ 1 file changed, 7 insertions(+)
diff --git a/net/compat.c b/net/compat.c index c48930373e65..53e933eb78b8 100644 --- a/net/compat.c +++ b/net/compat.c @@ -71,6 +71,13 @@ int get_compat_msghdr(struct msghdr *kmsg, struct compat_msghdr __user *umsg) __get_user(kmsg->msg_controllen, &umsg->msg_controllen) || __get_user(kmsg->msg_flags, &umsg->msg_flags)) return -EFAULT; + + if (!tmp1) + 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_name = compat_ptr(tmp1);
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