Commit Graph

5 Commits

Author SHA1 Message Date
Robert Reither
8479333ce7 rsa: crash in br_i32_decode() called from rsa_gen_key_prop()
Fixes problem for unaligned 32bit big-endian access in
lib/rsa/rsa-keyprop.c.

Exchanges br_i32_decode() with get_unaligned_be32().

This will keep the unaligned access for architectures capable and will do
some byte-shift magic for the not so capable ones.

Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Signed-by: Robert Reither <robert.reither@external.thalesgroup.com>
Remove unused include.
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
2020-09-14 23:28:52 +02:00
Heiko Stuebner
eda753be8a lib: rsa: free local arrays after use in rsa_gen_key_prop()
n, rr and rrtmp are used for internal calculations, but in the end
the results are copied into separately allocated elements of the
actual key_prop, so the n, rr and rrtmp elements are not used anymore
when returning from the function and should of course be freed.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-07-08 17:21:46 -04:00
Heiko Stuebner
49d0ea3746 lib: rsa: fix allocated size for rr and rrtmp in rsa_gen_key_prop()
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>
2020-07-08 17:21:46 -04:00
Heiko Stuebner
8434b43730 lib: rsa: bring exp_len in line when generating a key_prop
The exponent field of struct key_prop gets allocated an uint64_t,
and the contents are positioned from the back, so an exponent of
"0x01 0x00 0x01" becomes 0x0 0x0 0x0 0x0 0x0 0x1 0x0 0x1"

Right now rsa_gen_key_prop() allocates a uint64_t but sets exp_len
to the size returned from the parser, while on the other hand the
when getting the key from the devicetree exp_len always gets set to
sizeof(uint64_t).

So bring that in line with the established code.

Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
2020-07-08 17:21:46 -04:00
AKASHI Takahiro
e0d310b098 lib: rsa: generate additional parameters for public key
In the current implementation of FIT_SIGNATURE, five parameters for
a RSA public key are required while only two of them are essential.
(See rsa-mod-exp.h and uImage.FIT/signature.txt)
This is a result of considering relatively limited computer power
and resources on embedded systems, while such a assumption may not
be quite practical for other use cases.

In this patch, added is a function, rsa_gen_key_prop(), which will
generate additional parameters for other uses, in particular
UEFI secure boot, on the fly.

Note: the current code uses some "big number" routines from BearSSL
for the calculation.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
2020-03-12 08:20:39 -04:00