There could be a signed overflow in the following code. The expression, (32-logmask) is comprised between 0 and 31 included. It may be equal to 31. In such a case the left shift will produce a signed integer overflow. According to the C99 Standard, this is an undefined behavior. A simple fix is to replace the signed int 1 with the unsigned int 1U.
Showing the changes to include/linux (1 of 1 file). Show all
Unified · Split
| @@ -242,7 +242,7 @@ static inline void in_dev_put(struct in_device *idev) · 241 unmodified lines | ||
| 242 | 242 | static __inline__ __be32 inet_make_mask(int logmask) |
| 243 | 243 | { |
| 244 | 244 | if (logmask) |
| 245 | − return htonl(~((1<<(32-logmask))-1)); | |
| 245 | + return htonl(~((1U<<(32-logmask))-1)); | |
| 246 | 246 | return 0; |
| 247 | 247 | } |
| 248 | 248 | |