From: Colin Ian King colin.king@canonical.com
[ Upstream commit 332a9dd1d86f1e7203fc7f0fd7e82f0b304200fe ]
The shifting of the u8 integer returned fom ahc_inb(ahc, port+3) by 24 bits to the left will be promoted to a 32 bit signed int and then sign-extended to a u64. In the event that the top bit of the u8 is set then all then all the upper 32 bits of the u64 end up as also being set because of the sign-extension. Fix this by casting the u8 values to a u64 before the 24 bit left shift.
[ This dates back to 2002, I found the offending commit from the git history git://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git, commit f58eb66c0b0a ("Update aic7xxx driver to 6.2.10...") ]
Link: https://lore.kernel.org/r/20210621151727.20667-1-colin.king@canonical.com Signed-off-by: Colin Ian King colin.king@canonical.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Addresses-Coverity: ("Unintended sign extension") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/aic7xxx/aic7xxx_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/scsi/aic7xxx/aic7xxx_core.c b/drivers/scsi/aic7xxx/aic7xxx_core.c index 49e02e874553..fe15746af520 100644 --- a/drivers/scsi/aic7xxx/aic7xxx_core.c +++ b/drivers/scsi/aic7xxx/aic7xxx_core.c @@ -500,7 +500,7 @@ ahc_inq(struct ahc_softc *ahc, u_int port) return ((ahc_inb(ahc, port)) | (ahc_inb(ahc, port+1) << 8) | (ahc_inb(ahc, port+2) << 16) - | (ahc_inb(ahc, port+3) << 24) + | (((uint64_t)ahc_inb(ahc, port+3)) << 24) | (((uint64_t)ahc_inb(ahc, port+4)) << 32) | (((uint64_t)ahc_inb(ahc, port+5)) << 40) | (((uint64_t)ahc_inb(ahc, port+6)) << 48)