lib/mbedtls
1
0
Fork 0
mirror of https://github.com/Mbed-TLS/mbedtls.git synced 2025-07-29 11:41:15 +03:00
Code Activity

Merge remote-tracking branch 'origin/pr/2405' into development

Browse Source 
* origin/pr/2405:
  Fix ChangeLog entry ordering
  Fix typo
  Add non-regression test for buffer overflow
  Improve documentation of mbedtls_mpi_write_string()
  Adapt ChangeLog
  Fix 1-byte buffer overflow in mbedtls_mpi_write_string()
This commit is contained in:
Jaeden Amero
2019-04-05 14:08:49 +01:00
parent c7acf56504 b6a59f66cd
commit 62ab1f9961
4 changed files with 25 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

26
library/bignum.c
View File

@ -582,15 +582,20 @@ int mbedtls_mpi_write_string( const mbedtls_mpi *X, int radix,
if( radix < 2 || radix > 16 )
return( MBEDTLS_ERR_MPI_BAD_INPUT_DATA );
n = mbedtls_mpi_bitlen( X );
if( radix >= 4 ) n >>= 1;
if( radix >= 16 ) n >>= 1;
/*
* Round up the buffer length to an even value to ensure that there is
* enough room for hexadecimal values that can be represented in an odd
* number of digits.
*/
n += 3 + ( ( n + 1 ) & 1 );
n = mbedtls_mpi_bitlen( X ); /* Number of bits necessary to present `n`. */
if( radix >= 4 ) n >>= 1; /* Number of 4-adic digits necessary to present
* `n`. If radix > 4, this might be a strict
* overapproximation of the number of
* radix-adic digits needed to present `n`. */
if( radix >= 16 ) n >>= 1; /* Number of hexadecimal digits necessary to
* present `n`. */
n += 1; /* Terminating null byte */
n += 1; /* Compensate for the divisions above, which round down `n`
* in case it's not even. */
n += 1; /* Potential '-'-sign. */
n += ( n & 1 ); /* Make n even to have enough space for hexadecimal writing,
* which always uses an even number of hex-digits. */
if( buflen < n )
{
@ -602,7 +607,10 @@ int mbedtls_mpi_write_string( const mbedtls_mpi *X, int radix,
mbedtls_mpi_init( &T );
if( X->s == -1 )
{
*p++ = '-';
buflen--;
}
if( radix == 16 )
{