From: Heiko Stuebner heiko.stuebner@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 bit-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@gmx.de Signed-off-by: Heiko Stuebner heiko.stuebner@theobroma-systems.com Reviewed-by: Simon Glass sjg@chromium.org
rrtmp needs 2 + (((*prop)->num_bits * 2) >> 5) array elements.
Reviewed-by: Heinrich Schuchardt xypron.glpk@gmx.de --- v7: rrtmp needs one more u32. There is no label out. It is called err. --- lib/rsa/rsa-keyprop.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/lib/rsa/rsa-keyprop.c b/lib/rsa/rsa-keyprop.c index 9464df0093..e991031ec0 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), 2 + (((*prop)->num_bits * 2) >> 5)); + if (!n || !rr || !rrtmp) { + ret = -ENOMEM; + goto err; + } + /* exponent */ (*prop)->public_exponent = calloc(1, sizeof(uint64_t)); if (!(*prop)->public_exponent) { -- 2.27.0