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Commit 5362247a authored by Tilman Schmidt's avatar Tilman Schmidt Committed by David S. Miller
Browse files

isdn/capi: prevent index overrun from command_2_index() 



The result of the function command_2_index() is used to index two
arrays mnames[] and cpars[] with max. index 0x4e but in its current
form that function can produce results up to 3*(0x9+0x9)+0x7f =
0xb5.
Fix by clamping all result values potentially overrunning the arrays
to zero which is already handled as an invalid value.

Re-spotted with Coverity.

Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 9ea8aa8d

drivers/isdn/capi/capiutil.c

+2 −0
Original line number Original line Diff line number Diff line
@@ -207,6 +207,8 @@ static unsigned command_2_index(unsigned c, unsigned sc) 
		c = 0x9 + (c & 0x0f);

		c = 0x9 + (c & 0x0f);

	else if (c == 0x41)

	else if (c == 0x41)

		c = 0x9 + 0x1;

		c = 0x9 + 0x1;

	if (c > 0x18)

		c = 0x00;

	return (sc & 3) * (0x9 + 0x9) + c;

	return (sc & 3) * (0x9 + 0x9) + c;

}

}