From 438bf726def0f5bdc418b1c4ac038355a55f306a Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Tue, 5 Jun 2018 17:51:07 +0100 Subject: [PATCH] ipmi_si: fix potential integer overflow on large shift [ Upstream commit 97a103e6b584442cd848887ed8d47be2410b7e09 ] Shifting unsigned char b by an int type can lead to sign-extension overflow. For example, if b is 0xff and the shift is 24, then top bit is sign-extended so the final value passed to writeq has all the upper 32 bits set. Fix this by casting b to a 64 bit unsigned before the shift. Detected by CoverityScan, CID#1465246 ("Unintended sign extension") Signed-off-by: Colin Ian King Signed-off-by: Corey Minyard Signed-off-by: Sasha Levin --- drivers/char/ipmi/ipmi_si_mem_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/char/ipmi/ipmi_si_mem_io.c b/drivers/char/ipmi/ipmi_si_mem_io.c index 638f4ab..7558361 100644 --- a/drivers/char/ipmi/ipmi_si_mem_io.c +++ b/drivers/char/ipmi/ipmi_si_mem_io.c @@ -51,7 +51,7 @@ static unsigned char mem_inq(const struct si_sm_io *io, unsigned int offset) static void mem_outq(const struct si_sm_io *io, unsigned int offset, unsigned char b) { - writeq(b << io->regshift, (io->addr)+(offset * io->regspacing)); + writeq((u64)b << io->regshift, (io->addr)+(offset * io->regspacing)); } #endif -- 2.7.4