From: Jan Kiszka jan.kiszka@siemens.com

The fdt only provides 32-bit alignment of data. If the public_exponent happens to be not 64-bit aligned, we can trigger an exception on certain architectures. Seen on TI AM64x.

Note that the normal way of accessing such a number would be fdtdec_get_number. However, this is not available for tools, and this is one use case for lib/rsa.

Signed-off-by: Jan Kiszka jan.kiszka@siemens.com --- lib/rsa/rsa-mod-exp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/rsa/rsa-mod-exp.c b/lib/rsa/rsa-mod-exp.c index 420ab2eba0..4b9c4b1459 100644 --- a/lib/rsa/rsa-mod-exp.c +++ b/lib/rsa/rsa-mod-exp.c @@ -246,6 +246,11 @@ static void rsa_convert_big_endian(uint32_t *dst, const uint32_t *src, int len) dst[i] = fdt32_to_cpu(src[len - 1 - i]); }

+static uint64_t fdt64_get(const uint32_t *data) +{ + return ((uint64_t)fdt32_to_cpu(data[0]) << 32) | fdt32_to_cpu(data[1]); +} + int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len, struct key_prop *prop, uint8_t *out) { @@ -262,8 +267,7 @@ int rsa_mod_exp_sw(const uint8_t *sig, uint32_t sig_len, if (!prop->public_exponent) key.exponent = RSA_DEFAULT_PUBEXP; else - key.exponent = - fdt64_to_cpu(*((uint64_t *)(prop->public_exponent))); + key.exponent = fdt64_get(prop->public_exponent);

if (!key.len || !prop->modulus || !prop->rr) { debug("%s: Missing RSA key info", __func__);