This is especially important in cases where the kernel allocs a new structure and expects a field to be set from a netlink attribute. If such attribute is shorter than expected, the rest of the field is left containing previous data. When such field is read back by the user space, kernel memory content is leaked.
Unified · Split
| @@ -279,6 +279,8 @@ int nla_memcpy(void *dest, const struct nlattr *src, int count) · 278 unmodified lines | |||
| 279 | int minlen = min_t(int, count, nla_len(src)); | 279 | int minlen = min_t(int, count, nla_len(src)); |
| 280 | 280 | ||
| 281 | memcpy(dest, nla_data(src), minlen); | 281 | memcpy(dest, nla_data(src), minlen); |
| 282 | if (count > minlen) | ||
| 283 | memset(dest + minlen, 0, count - minlen); | ||
| 282 | 284 | ||
| 283 | return minlen; | 285 | return minlen; |
| 284 | } | 286 | } |