| Message ID | 20200618142328.1753036-4-heiko@sntech.de |
|---|---|
| State | New |
| Headers | show |
| Series | [v6,1/8] lib: rsa: distinguish between tpl and spl for CONFIG_RSA_VERIFY | expand |
On Thu, 18 Jun 2020 at 08:23, Heiko Stuebner <heiko at sntech.de> wrote: > > From: Heiko Stuebner <heiko.stuebner at theobroma-systems.com> > > When calculating rrtmp/rr rsa_gen_key_prop() tries to make > (((rlen + 31) >> 5) + 1) steps in the rr uint32_t array and > (((rlen + 7) >> 3) + 1) / 4 steps in uint32_t rrtmp[] > with rlen being num_bits * 2 > > On a 4096bit key this comes down to to 257 uint32_t elements > in rr and 256 elements in rrtmp but with the current allocation > rr and rrtmp only have 129 uint32_t elements. > > On 2048bit keys this works by chance as the defined max_rsa_size=4096 > allocates a suitable number of elements, but with an actual 4096bit key > this results in other memory parts getting overwritten. > > So as suggested by Heinrich Schuchardt just use the actual bis-size > of the key as base for the size calculation, in turn making the code > compatible to any future keysizes. > > Suggested-by: Heinrich Schuchardt <xypron.debian at gmx.de> > Signed-off-by: Heiko Stuebner <heiko.stuebner at theobroma-systems.com> > --- > changes in v6: > - drop max_rsa_size and use the keysize as base > changes in v4: > - new patch > > lib/rsa/rsa-keyprop.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) Reviewed-by: Simon Glass <sjg at chromium.org>
diff --git a/lib/rsa/rsa-keyprop.c b/lib/rsa/rsa-keyprop.c index 4b54db44c4..83b942615f 100644 --- a/lib/rsa/rsa-keyprop.c +++ b/lib/rsa/rsa-keyprop.c @@ -654,14 +654,10 @@ int rsa_gen_key_prop(const void *key, uint32_t keylen, struct key_prop **prop) { struct rsa_key rsa_key; uint32_t *n = NULL, *rr = NULL, *rrtmp = NULL; - const int max_rsa_size = 4096; int rlen, i, ret; *prop = calloc(sizeof(**prop), 1); - n = calloc(sizeof(uint32_t), 1 + (max_rsa_size >> 5)); - rr = calloc(sizeof(uint32_t), 1 + (max_rsa_size >> 5)); - rrtmp = calloc(sizeof(uint32_t), 1 + (max_rsa_size >> 5)); - if (!(*prop) || !n || !rr || !rrtmp) { + if (!(*prop)) { ret = -ENOMEM; goto err; } @@ -682,6 +678,14 @@ int rsa_gen_key_prop(const void *key, uint32_t keylen, struct key_prop **prop) } memcpy((void *)(*prop)->modulus, &rsa_key.n[i], rsa_key.n_sz - i); + n = calloc(sizeof(uint32_t), 1 + ((*prop)->num_bits >> 5)); + rr = calloc(sizeof(uint32_t), 1 + (((*prop)->num_bits * 2) >> 5)); + rrtmp = calloc(sizeof(uint32_t), 1 + (((*prop)->num_bits * 2) >> 5)); + if (!n || !rr || !rrtmp) { + ret = -ENOMEM; + goto out; + } + /* exponent */ (*prop)->public_exponent = calloc(1, sizeof(uint64_t)); if (!(*prop)->public_exponent) {