path: root/security
diff options
authorTycho Andersen <tycho@tycho.ws>2018-04-24 14:26:39 -0600
committerJames Morris <james.morris@microsoft.com>2018-05-11 13:07:49 -0700
commit890e2abe1028c39e5399101a2c277219cd637aaa (patch)
tree6e3997847bd92871d1ee00916fcd04d59f19126a /security
parentdh key: get rid of stack allocated array (diff)
dh key: get rid of stack allocated array for zeroes
We're interested in getting rid of all of the stack allocated arrays in the kernel: https://lkml.org/lkml/2018/3/7/621 This case is interesting, since we really just need an array of bytes that are zero. The loop already ensures that if the array isn't exactly the right size that enough zero bytes will be copied in. So, instead of choosing this value to be the size of the hash, let's just choose it to be 32, since that is a common size, is not too big, and will not result in too many extra iterations of the loop. v2: split out from other patch, just hardcode array size instead of dynamically allocating something the right size v3: fix typo of 256 -> 32 Signed-off-by: Tycho Andersen <tycho@tycho.ws> Reviewed-by: Kees Cook <keescook@chromium.org> CC: David Howells <dhowells@redhat.com> CC: James Morris <jmorris@namei.org> CC: "Serge E. Hallyn" <serge@hallyn.com> CC: Eric Biggers <ebiggers3@gmail.com> Signed-off-by: James Morris <james.morris@microsoft.com>
Diffstat (limited to 'security')
1 files changed, 3 insertions, 3 deletions
diff --git a/security/keys/dh.c b/security/keys/dh.c
index 9fecaea6c298..f7403821db7f 100644
--- a/security/keys/dh.c
+++ b/security/keys/dh.c
@@ -162,8 +162,8 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
goto err;
if (zlen && h) {
- u8 tmpbuffer[h];
- size_t chunk = min_t(size_t, zlen, h);
+ u8 tmpbuffer[32];
+ size_t chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
memset(tmpbuffer, 0, chunk);
do {
@@ -173,7 +173,7 @@ static int kdf_ctr(struct kdf_sdesc *sdesc, const u8 *src, unsigned int slen,
goto err;
zlen -= chunk;
- chunk = min_t(size_t, zlen, h);
+ chunk = min_t(size_t, zlen, sizeof(tmpbuffer));
} while (zlen);