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ipmi_si: fix potential integer overflow on large shift

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[ 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 <colin.king@canonical.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Colin Ian King 2018-06-05 17:51:07 +01:00 committed by Greg Kroah-Hartman
parent 78538bae1d
commit 438bf726de
1 changed files with 1 additions and 1 deletions
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2
drivers/char/ipmi/ipmi_si_mem_io.c
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@ -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