diff options
| author | Daniel Borkmann <dborkman@redhat.com> | 2014-08-26 23:16:35 -0400 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-12-14 16:23:49 +0000 |
| commit | 2bdb21fe06c81e977e2bcf1ad3063ba96db9563f (patch) | |
| tree | 0dbabf22202517c4a15db4814223314ab4355e39 /include | |
| parent | ce2584379f31cfc44bbe770bb78430950a24156e (diff) | |
random: add and use memzero_explicit() for clearing data
commit d4c5efdb97773f59a2b711754ca0953f24516739 upstream.
zatimend has reported that in his environment (3.16/gcc4.8.3/corei7)
memset() calls which clear out sensitive data in extract_{buf,entropy,
entropy_user}() in random driver are being optimized away by gcc.
Add a helper memzero_explicit() (similarly as explicit_bzero() variants)
that can be used in such cases where a variable with sensitive data is
being cleared out in the end. Other use cases might also be in crypto
code. [ I have put this into lib/string.c though, as it's always built-in
and doesn't need any dependencies then. ]
Fixes kernel bugzilla: 82041
Reported-by: zatimend@hotmail.co.uk
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
[bwh: Backported to 3.2:
- extract_buf() needs to use this for the 'extract' array as well
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/string.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h index e033564f10ba..8515a4dbc1c9 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -144,5 +144,7 @@ static inline bool strstarts(const char *str, const char *prefix) { return strncmp(str, prefix, strlen(prefix)) == 0; } + +void memzero_explicit(void *s, size_t count); #endif #endif /* _LINUX_STRING_H_ */ |