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Commit 5510ab18 authored by Tilman Schmidt's avatar Tilman Schmidt Committed by David S. Miller
Browse files

isdn/capi: prevent NULL pointer dereference on invalid CAPI command 



An invalid CAPI 2.0 command/subcommand combination may retrieve a
NULL pointer from the cpars[] array which will later be dereferenced
by the parser routines.
Fix by adding NULL pointer checks in strategic places.

Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 854d23b7

drivers/isdn/capi/capiutil.c

+7 −0
Original line number Diff line number Diff line
@@ -318,6 +318,8 @@ unsigned capi_cmsg2message(_cmsg *cmsg, u8 *msg) 
	cmsg->l = 8;

	cmsg->p = 0;

	cmsg->par = capi_cmd2par(cmsg->Command, cmsg->Subcommand);

	if (!cmsg->par)

		return 1;	/* invalid command/subcommand */



	pars_2_message(cmsg);
@@ -391,6 +393,8 @@ unsigned capi_message2cmsg(_cmsg *cmsg, u8 *msg) 
	byteTRcpy(cmsg->m + 4, &cmsg->Command);

	byteTRcpy(cmsg->m + 5, &cmsg->Subcommand);

	cmsg->par = capi_cmd2par(cmsg->Command, cmsg->Subcommand);

	if (!cmsg->par)

		return 1;	/* invalid command/subcommand */



	message_2_pars(cmsg);
@@ -640,6 +644,9 @@ static _cdebbuf *printstruct(_cdebbuf *cdb, u8 *m) 


static _cdebbuf *protocol_message_2_pars(_cdebbuf *cdb, _cmsg *cmsg, int level)

{

	if (!cmsg->par)

		return NULL;	/* invalid command/subcommand */



	for (; TYP != _CEND; cmsg->p++) {

		int slen = 29 + 3 - level;

		int i;