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NetworkPkg/Ip6Dxe: Improve Neightbor Discovery message validation. 

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=2174

Problem has been identified with Ip6ProcessRouterAdvertise() when
Router Advertise packet contains options with malicious/invalid
'Length' field. This can lead to platform entering infinite loop
when processing options from that packet.

Cc: Jiaxin Wu <jiaxin.wu@intel.com>
Cc: Siyuan Fu <siyuan.fu@intel.com>
Signed-off-by: Maciej Rabeda <maciej.rabeda@linux.intel.com>
Reviewed-by: Siyuan Fu <siyuan.fu@intel.com>
This commit is contained in:
Maciej Rabeda 2020-03-02 13:25:20 +01:00 committed by mergify[bot]
parent 3000c2963d
commit 9c20342eed
3 changed files with 84 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
NetworkPkg/Ip6Dxe/Ip6Nd.c
View File

@ -1927,7 +1927,7 @@ Ip6ProcessRouterAdvertise (
UINT32 ReachableTime;
UINT32 RetransTimer;
UINT16 RouterLifetime;
UINT16 Offset;
UINT32 Offset;
UINT8 Type;
UINT8 Length;
IP6_ETHER_ADDR_OPTION LinkLayerOption;
@ -2094,10 +2094,11 @@ Ip6ProcessRouterAdvertise (
//
// The only defined options that may appear are the Source
// Link-Layer Address, Prefix information and MTU options.
// All included options have a length that is greater than zero.
// All included options have a length that is greater than zero and
// fit within the input packet.
//
Offset = 16;
while (Offset < Head->PayloadLength) {
while (Offset < (UINT32) Head->PayloadLength) {
NetbufCopy (Packet, Offset, sizeof (UINT8), &Type);
switch (Type) {
case Ip6OptionEtherSource:
@ -2105,9 +2106,12 @@ Ip6ProcessRouterAdvertise (
// Update the neighbor cache
//
NetbufCopy (Packet, Offset, sizeof (IP6_ETHER_ADDR_OPTION), (UINT8 *) &LinkLayerOption);
if (LinkLayerOption.Length <= 0) {
goto Exit;
}
//
// Option size validity ensured by Ip6IsNDOptionValid().
//
ASSERT (LinkLayerOption.Length != 0);
ASSERT (Offset + (UINT32) LinkLayerOption.Length * 8 >= (UINT32) Head->PayloadLength);
ZeroMem (&LinkLayerAddress, sizeof (EFI_MAC_ADDRESS));
CopyMem (&LinkLayerAddress, LinkLayerOption.EtherAddr, 6);
@ -2151,13 +2155,17 @@ Ip6ProcessRouterAdvertise (
}
}
Offset = (UINT16) (Offset + (UINT16) LinkLayerOption.Length * 8);
Offset += (UINT32) LinkLayerOption.Length * 8;
break;
case Ip6OptionPrefixInfo:
NetbufCopy (Packet, Offset, sizeof (IP6_PREFIX_INFO_OPTION), (UINT8 *) &PrefixOption);
if (PrefixOption.Length != 4) {
goto Exit;
}
//
// Option size validity ensured by Ip6IsNDOptionValid().
//
ASSERT (PrefixOption.Length == 4);
ASSERT (Offset + (UINT32) PrefixOption.Length * 8 >= (UINT32) Head->PayloadLength);
PrefixOption.ValidLifetime = NTOHL (PrefixOption.ValidLifetime);
PrefixOption.PreferredLifetime = NTOHL (PrefixOption.PreferredLifetime);
@ -2321,9 +2329,12 @@ Ip6ProcessRouterAdvertise (
break;
case Ip6OptionMtu:
NetbufCopy (Packet, Offset, sizeof (IP6_MTU_OPTION), (UINT8 *) &MTUOption);
if (MTUOption.Length != 1) {
goto Exit;
}
//
// Option size validity ensured by Ip6IsNDOptionValid().
//
ASSERT (MTUOption.Length == 1);
ASSERT (Offset + (UINT32) MTUOption.Length * 8 >= (UINT32) Head->PayloadLength);
//
// Use IPv6 minimum link MTU 1280 bytes as the maximum packet size in order
@ -2338,11 +2349,10 @@ Ip6ProcessRouterAdvertise (
// Silently ignore unrecognized options
//
NetbufCopy (Packet, Offset + sizeof (UINT8), sizeof (UINT8), &Length);
if (Length <= 0) {
goto Exit;
}
Offset = (UINT16) (Offset + (UINT16) Length * 8);
ASSERT (Length != 0);
Offset += (UINT32) Length * 8;
break;
}
}

13
NetworkPkg/Ip6Dxe/Ip6Nd.h
View File

@ -56,12 +56,21 @@ VOID
VOID *Context
);
typedef struct _IP6_OPTION_HEADER {
UINT8 Type;
UINT8 Length;
} IP6_OPTION_HEADER;
STATIC_ASSERT (sizeof (IP6_OPTION_HEADER) == 2, "IP6_OPTION_HEADER is expected to be exactly 2 bytes long.");
typedef struct _IP6_ETHE_ADDR_OPTION {
UINT8 Type;
UINT8 Length;
UINT8 EtherAddr[6];
} IP6_ETHER_ADDR_OPTION;
STATIC_ASSERT (sizeof (IP6_ETHER_ADDR_OPTION) == 8, "IP6_ETHER_ADDR_OPTION is expected to be exactly 8 bytes long.");
typedef struct _IP6_MTU_OPTION {
UINT8 Type;
UINT8 Length;
@ -69,6 +78,8 @@ typedef struct _IP6_MTU_OPTION {
UINT32 Mtu;
} IP6_MTU_OPTION;
STATIC_ASSERT (sizeof (IP6_MTU_OPTION) == 8, "IP6_MTU_OPTION is expected to be exactly 8 bytes long.");
typedef struct _IP6_PREFIX_INFO_OPTION {
UINT8 Type;
UINT8 Length;
@ -80,6 +91,8 @@ typedef struct _IP6_PREFIX_INFO_OPTION {
EFI_IPv6_ADDRESS Prefix;
} IP6_PREFIX_INFO_OPTION;
STATIC_ASSERT (sizeof (IP6_PREFIX_INFO_OPTION) == 32, "IP6_PREFIX_INFO_OPTION is expected to be exactly 32 bytes long.");
typedef
VOID
(*IP6_DAD_CALLBACK) (

59
NetworkPkg/Ip6Dxe/Ip6Option.c
View File

@ -129,45 +129,74 @@ Ip6IsNDOptionValid (
IN UINT16 OptionLen
)
{
UINT16 Offset;
UINT8 OptionType;
UINT32 Offset;
UINT16 Length;
IP6_OPTION_HEADER *OptionHeader;
if (Option == NULL) {
ASSERT (Option != NULL);
return FALSE;
}
Offset = 0;
while (Offset < OptionLen) {
OptionType = *(Option + Offset);
Length = (UINT16) (*(Option + Offset + 1) * 8);
//
// RFC 4861 states that Neighbor Discovery packet can contain zero or more
// options. Start processing the options if at least Type + Length fields
// fit within the input buffer.
//
while (Offset + sizeof (IP6_OPTION_HEADER) - 1 < OptionLen) {
OptionHeader = (IP6_OPTION_HEADER*) (Option + Offset);
Length = (UINT16) OptionHeader->Length * 8;
switch (OptionType) {
switch (OptionHeader->Type) {
case Ip6OptionPrefixInfo:
if (Length != 32) {
return FALSE;
}
break;
case Ip6OptionMtu:
if (Length != 8) {
return FALSE;
}
break;
default:
// RFC 4861 states that Length field cannot be 0.
if (Length == 0) {
return FALSE;
}
break;
}
//
// Check whether recognized options are within the input buffer's scope.
//
switch (OptionHeader->Type) {
case Ip6OptionEtherSource:
case Ip6OptionEtherTarget:
case Ip6OptionPrefixInfo:
case Ip6OptionRedirected:
case Ip6OptionMtu:
if (Offset + Length > (UINT32) OptionLen) {
return FALSE;
}
break;
default:
//
// Check the length of Ip6OptionEtherSource, Ip6OptionEtherTarget, and
// Ip6OptionRedirected here. For unrecognized options, silently ignore
// and continue processing the message.
// Unrecognized options can be either valid (but unused) or invalid
// (garbage in between or right after valid options). Silently ignore.
//
if (Length == 0) {
return FALSE;
}
break;
}
Offset = (UINT16) (Offset + Length);
//
// Advance to the next option.
// Length already considers option header's Type + Length.
//
Offset += Length;
}
return TRUE;