From 97a103e6b584442cd848887ed8d47be2410b7e09 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Tue, 5 Jun 2018 17:51:07 +0100 Subject: ipmi_si: fix potential integer overflow on large shift 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 --- drivers/char/ipmi/ipmi_si_mem_io.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/char/ipmi') diff --git a/drivers/char/ipmi/ipmi_si_mem_io.c b/drivers/char/ipmi/ipmi_si_mem_io.c index 1b869d530884..fd0ec8d6bf0e 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 -- cgit v1.2.3