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Use additional state in CCM to track auth data input.

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Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
This commit is contained in:
Mateusz Starzyk 2021-08-09 15:53:41 +02:00
parent 4f2dd8aada
commit 62d22f9782
1 changed files with 9 additions and 8 deletions
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17
library/ccm.c
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@ -100,7 +100,8 @@ void mbedtls_ccm_free( mbedtls_ccm_context *ctx )
#define CCM_STATE__CLEAR 0 #define CCM_STATE__CLEAR 0
#define CCM_STATE__STARTED (1 << 0) #define CCM_STATE__STARTED (1 << 0)
#define CCM_STATE__LENGHTS_SET (1 << 1) #define CCM_STATE__LENGHTS_SET (1 << 1)
#define CCM_STATE__AUTH_DATA_FINISHED (1 << 2) #define CCM_STATE__AUTH_DATA_STARTED (1 << 2)
#define CCM_STATE__AUTH_DATA_FINISHED (1 << 3)
#define CCM_STATE__ERROR (1 << 4) #define CCM_STATE__ERROR (1 << 4)
/* /*
@ -272,7 +273,7 @@ int mbedtls_ccm_update_ad( mbedtls_ccm_context *ctx,
return MBEDTLS_ERR_CCM_BAD_SEQUENCE; return MBEDTLS_ERR_CCM_BAD_SEQUENCE;
} }
if( ctx->processed == 0 ) if( !(ctx->state & CCM_STATE__AUTH_DATA_STARTED) )
{ {
if ( add_len > ctx->add_len ) if ( add_len > ctx->add_len )
{ {
@ -282,17 +283,17 @@ int mbedtls_ccm_update_ad( mbedtls_ccm_context *ctx,
ctx->y[0] ^= (unsigned char)( ( ctx->add_len >> 8 ) & 0xFF ); ctx->y[0] ^= (unsigned char)( ( ctx->add_len >> 8 ) & 0xFF );
ctx->y[1] ^= (unsigned char)( ( ctx->add_len ) & 0xFF ); ctx->y[1] ^= (unsigned char)( ( ctx->add_len ) & 0xFF );
ctx->processed += 2; ctx->state |= CCM_STATE__AUTH_DATA_STARTED;
} }
else if ( ctx->processed - 2 + add_len > ctx->add_len ) else if ( ctx->processed + add_len > ctx->add_len )
{ {
return MBEDTLS_ERR_CCM_BAD_INPUT; return MBEDTLS_ERR_CCM_BAD_INPUT;
} }
while( add_len > 0 ) while( add_len > 0 )
{ {
offset = ctx->processed % 16; offset = (ctx->processed + 2) % 16; /* account for y[0] and y[1]
* holding total auth data length */
use_len = 16 - offset; use_len = 16 - offset;
if( use_len > add_len ) if( use_len > add_len )
@ -305,7 +306,7 @@ int mbedtls_ccm_update_ad( mbedtls_ccm_context *ctx,
add_len -= use_len; add_len -= use_len;
add += use_len; add += use_len;
if( use_len + offset == 16 || ctx->processed - 2 == ctx->add_len ) if( use_len + offset == 16 || ctx->processed == ctx->add_len )
{ {
if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 ) if( ( ret = mbedtls_cipher_update( &ctx->cipher_ctx, ctx->y, 16, ctx->y, &olen ) ) != 0 )
{ {
@ -315,7 +316,7 @@ int mbedtls_ccm_update_ad( mbedtls_ccm_context *ctx,
} }
} }
if( ctx->processed - 2 == ctx->add_len ) if( ctx->processed == ctx->add_len )
{ {
ctx->state |= CCM_STATE__AUTH_DATA_FINISHED; ctx->state |= CCM_STATE__AUTH_DATA_FINISHED;
ctx->processed = 0; // prepare for mbedtls_ccm_update() ctx->processed = 0; // prepare for mbedtls_ccm_update()