From: Colin Ian King Date: Mon, 21 Jun 2021 15:17:27 +0000 (+0100) Subject: scsi: aic7xxx: Fix unintentional sign extension issue on left shift of u8 X-Git-Tag: v4.4.277~40 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=165717ea4660a5ac5b992cf79779542b12e13aa6;p=thirdparty%2Fkernel%2Fstable.git scsi: aic7xxx: Fix unintentional sign extension issue on left shift of u8 [ 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 Signed-off-by: Martin K. Petersen Addresses-Coverity: ("Unintended sign extension") Signed-off-by: Sasha Levin --- diff --git a/drivers/scsi/aic7xxx/aic7xxx_core.c b/drivers/scsi/aic7xxx/aic7xxx_core.c index def3208dd2905..9b5832b46deca 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)