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

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 <[email protected]> Signed-off-by: David S. Miller <[email protected]>
ambv · Jan 17, 2019 · cb12d72 · cb12d72
1 parent 0f149c9
commit cb12d72
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/drivers/atm/he.c b/drivers/atm/he.c
@@ -718,7 +718,7 @@ 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 */