From: Kees Cook keescook@chromium.org
[ Upstream commit f5912cc19acd7c24b2dbf65a6340bf194244f085 ]
Using MKWORD() on a byte-sized variable results in OOB read. Expand the size of the reserved area so both MKWORD and MKBYTE continue to work without overflow. Silences this warning on a -Warray-bounds build:
drivers/char/mwave/3780i.h:346:22: error: array subscript 'short unsigned int[0]' is partly outside array bounds of 'DSP_ISA_SLAVE_CONTROL[1]' [-Werror=array-bounds] 346 | #define MKWORD(var) (*((unsigned short *)(&var))) | ~^~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/char/mwave/3780i.h:356:40: note: in definition of macro 'OutWordDsp' 356 | #define OutWordDsp(index,value) outw(value,usDspBaseIO+index) | ^~~~~ drivers/char/mwave/3780i.c:373:41: note: in expansion of macro 'MKWORD' 373 | OutWordDsp(DSP_IsaSlaveControl, MKWORD(rSlaveControl)); | ^~~~~~ drivers/char/mwave/3780i.c:358:31: note: while referencing 'rSlaveControl' 358 | DSP_ISA_SLAVE_CONTROL rSlaveControl; | ^~~~~~~~~~~~~
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kees Cook keescook@chromium.org Link: https://lore.kernel.org/r/20211203084206.3104326-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/mwave/3780i.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/mwave/3780i.h b/drivers/char/mwave/3780i.h index 9ccb6b270b071..95164246afd1a 100644 --- a/drivers/char/mwave/3780i.h +++ b/drivers/char/mwave/3780i.h @@ -68,7 +68,7 @@ typedef struct { unsigned char ClockControl:1; /* RW: Clock control: 0=normal, 1=stop 3780i clocks */ unsigned char SoftReset:1; /* RW: Soft reset 0=normal, 1=soft reset active */ unsigned char ConfigMode:1; /* RW: Configuration mode, 0=normal, 1=config mode */ - unsigned char Reserved:5; /* 0: Reserved */ + unsigned short Reserved:13; /* 0: Reserved */ } DSP_ISA_SLAVE_CONTROL;