iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

atm: he: fix sign-extension overflow on large shift

Browse Source 
[ Upstream commit cb12d72b27a6f41325ae23a11033cf5fedfa1b97 ]

Shifting the 1 by exp by an int can lead to sign-extension overlow when
exp is 31 since 1 is an signed int and sign-extending this result to an
unsigned long long will set the upper 32 bits.  Fix this by shifting an
unsigned long.

Detected by cppcheck:
(warning) Shifting signed 32-bit value by 31 bits is undefined behaviour

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Colin Ian King 2019-01-15 18:03:38 +00:00 committed by Greg Kroah-Hartman
parent 46154d295b
commit 364f376146
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/atm/he.c
View File

@ -717,7 +717,7 @@ static int he_init_cs_block_rcm(struct he_dev *he_dev)
instead of '/ 512', use '>> 9' to prevent a call
to divdu3 on x86 platforms
*/
rate_cps = (unsigned long long) (1 << exp) * (man + 512) >> 9;
rate_cps = (unsigned long long) (1UL << exp) * (man + 512) >> 9;
if (rate_cps < 10)
rate_cps = 10; /* 2.2.1 minimum payload rate is 10 cps */