linux/lib/mpi
Nicolai Stange 03cdfaad49 lib/mpi: mpi_read_from_buffer(): return error code
mpi_read_from_buffer() reads a MPI from a buffer into a newly allocated
MPI instance. It expects the buffer's leading two bytes to contain the
number of bits, followed by the actual payload.

On failure, it returns NULL and updates the in/out argument ret_nread
somewhat inconsistently:
- If the given buffer is too short to contain the leading two bytes
  encoding the number of bits or their value is unsupported, then
  ret_nread will be cleared.
- If the allocation of the resulting MPI instance fails, ret_nread is left
  as is.

The only user of mpi_read_from_buffer(), digsig_verify_rsa(), simply checks
for a return value of NULL and returns -ENOMEM if that happens.

While this is all of cosmetic nature only, there is another error condition
which currently isn't detectable by the caller of mpi_read_from_buffer():
if the given buffer is too small to hold the number of bits as encoded in
its first two bytes, the return value will be non-NULL and *ret_nread > 0.

In preparation of communicating this condition to the caller, let
mpi_read_from_buffer() return error values by means of the ERR_PTR()
mechanism.

Make the sole caller of mpi_read_from_buffer(), digsig_verify_rsa(),
check the return value for IS_ERR() rather than == NULL. If IS_ERR() is
true, return the associated error value rather than the fixed -ENOMEM.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-05-31 16:41:59 +08:00
..
generic_mpih-add1.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-lshift.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-mul1.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-mul2.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-mul3.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-rshift.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
generic_mpih-sub1.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
longlong.h lib/mpi: avoid assembler warning 2016-02-28 03:26:34 +08:00
Makefile MPILIB: Reinstate mpi_cmp[_ui]() and export for RSA signature verification 2012-10-08 13:50:15 +10:30
mpi-bit.c MPILIB: Provide count_leading/trailing_zeros() based on arch functions 2012-10-08 13:50:11 +10:30
mpi-cmp.c MPILIB: Fix comparison of negative MPIs 2015-01-14 16:10:12 +00:00
mpi-inline.h lib/mpi: use "static inline" instead of "extern inline" 2016-02-28 03:26:34 +08:00
mpi-internal.h lib/mpi: use "static inline" instead of "extern inline" 2016-02-28 03:26:34 +08:00
mpi-pow.c MPILIB: Provide count_leading/trailing_zeros() based on arch functions 2012-10-08 13:50:11 +10:30
mpicoder.c lib/mpi: mpi_read_from_buffer(): return error code 2016-05-31 16:41:59 +08:00
mpih-cmp.c crypto: GnuPG based MPI lib - source files (part 1) 2011-11-09 11:45:22 +02:00
mpih-div.c Remove unused code from MPI library 2012-05-26 11:51:03 +10:00
mpih-mul.c Remove unused code from MPI library 2012-05-26 11:51:03 +10:00
mpiutil.c MPILIB: add mpi_read_buf() and mpi_get_size() helpers 2015-06-16 14:35:06 +08:00