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Fixed UB due to int promotion before shifting of u8 values

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Added casts to u32 for 'rcons' and 'Td4s' which are of type uint8_t*, so their elements, before being shifted, are promoted to int (not to unsigned int) unless explicitly casted, due to integer promotion rules of the C language.

This caused the "left shift of * by 24 places cannot be represented in type 'int'" error when compiling with GCC's -fsanitize=undefined.

The code is from an old version of wpa_supplicant/hostapd.
This commit is contained in:
wiire-a 2017-12-31 12:43:24 +01:00
parent 6438a9cf29
commit 7576a68717
1 changed files with 11 additions and 2 deletions
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13
src/crypto/aes_i.h
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@ -11,6 +11,13 @@
*
* See README and COPYING for more details.
*/
/*
* This file was modified for use in pixiewps
* - Added casts to u32 for 'rcons' and 'Td4s' which are of type uint8_t*,
* so their elements, before being shifted,
* are promoted to int (not to unsigned int) unless explicitly casted,
* due to integer promotion rules of the C language
*/
#ifndef AES_I_H
#define AES_I_H
@ -66,7 +73,8 @@ extern const u8 rcons[10];
#else /* AES_SMALL_TABLES */
#define RCON(i) (rcons[(i)] << 24)
/* NOTE: Added cast to u32 ('rcons' is of type uint8_t*) */
#define RCON(i) ((u32)rcons[(i)] << 24)
static inline u32 rotr(u32 val, int bits)
{
@ -91,7 +99,8 @@ static inline u32 rotr(u32 val, int bits)
#define TD1(i) rotr(Td0[((i) >> 16) & 0xff], 8)
#define TD2(i) rotr(Td0[((i) >> 8) & 0xff], 16)
#define TD3(i) rotr(Td0[(i) & 0xff], 24)
#define TD41(i) (Td4s[((i) >> 24) & 0xff] << 24)
/* NOTE: Added cast to u32 ('Td4s' is of type uint8_t*) */
#define TD41(i) ((u32)Td4s[((i) >> 24) & 0xff] << 24)
#define TD42(i) (Td4s[((i) >> 16) & 0xff] << 16)
#define TD43(i) (Td4s[((i) >> 8) & 0xff] << 8)
#define TD44(i) (Td4s[(i) & 0xff])