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strscpy: zero any trailing garbage bytes in the destination

It's possible that the destination can be shadowed in userspace
(as, for example, the perf buffers are now).  So we should take
care not to leak data that could be inspected by userspace.

Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com>
steinar/wifi_calib_4_9_kernel
Chris Metcalf 2015-10-06 12:37:41 -04:00
parent c753bf34c9
commit 990486c8af
1 changed files with 2 additions and 1 deletions

View File

@ -203,12 +203,13 @@ ssize_t strscpy(char *dest, const char *src, size_t count)
unsigned long c, data;
c = *(unsigned long *)(src+res);
*(unsigned long *)(dest+res) = c;
if (has_zero(c, &data, &constants)) {
data = prep_zero_mask(c, data, &constants);
data = create_zero_mask(data);
*(unsigned long *)(dest+res) = c & zero_bytemask(data);
return res + find_zero(data);
}
*(unsigned long *)(dest+res) = c;
res += sizeof(unsigned long);
count -= sizeof(unsigned long);
max -= sizeof(unsigned long);