From 06c03cac9487555478c7d80065ebf7818bf6fd06 Mon Sep 17 00:00:00 2001 From: Lennert Buytenhek Date: Mon, 7 Nov 2005 21:12:07 +0000 Subject: [PATCH] [ARM] 3117/1: nwfpe kernel memory info leak Patch from Lennert Buytenhek The routine that nwfpe uses for converting floats/doubles to extended precision fails to zero two bytes of kernel stack. This is not immediately obvious, as the floatx80 structure has 16 bits of implicit padding (by design.) These two bytes are copied to userspace when an stfe is emulated, causing a possible info leak. Make the padding explicit and zero it out in the relevant places. Signed-off-by: Lennert Buytenhek Signed-off-by: Russell King --- arch/arm/nwfpe/fpopcode.c | 16 ++++++++-------- arch/arm/nwfpe/softfloat-specialize | 1 + arch/arm/nwfpe/softfloat.c | 6 ++++++ arch/arm/nwfpe/softfloat.h | 1 + 4 files changed, 16 insertions(+), 8 deletions(-) diff --git a/arch/arm/nwfpe/fpopcode.c b/arch/arm/nwfpe/fpopcode.c index 4c9f570..67ff2ab 100644 --- a/arch/arm/nwfpe/fpopcode.c +++ b/arch/arm/nwfpe/fpopcode.c @@ -29,14 +29,14 @@ #ifdef CONFIG_FPE_NWFPE_XP const floatx80 floatx80Constant[] = { - {0x0000, 0x0000000000000000ULL}, /* extended 0.0 */ - {0x3fff, 0x8000000000000000ULL}, /* extended 1.0 */ - {0x4000, 0x8000000000000000ULL}, /* extended 2.0 */ - {0x4000, 0xc000000000000000ULL}, /* extended 3.0 */ - {0x4001, 0x8000000000000000ULL}, /* extended 4.0 */ - {0x4001, 0xa000000000000000ULL}, /* extended 5.0 */ - {0x3ffe, 0x8000000000000000ULL}, /* extended 0.5 */ - {0x4002, 0xa000000000000000ULL} /* extended 10.0 */ + { .high = 0x0000, .low = 0x0000000000000000ULL},/* extended 0.0 */ + { .high = 0x3fff, .low = 0x8000000000000000ULL},/* extended 1.0 */ + { .high = 0x4000, .low = 0x8000000000000000ULL},/* extended 2.0 */ + { .high = 0x4000, .low = 0xc000000000000000ULL},/* extended 3.0 */ + { .high = 0x4001, .low = 0x8000000000000000ULL},/* extended 4.0 */ + { .high = 0x4001, .low = 0xa000000000000000ULL},/* extended 5.0 */ + { .high = 0x3ffe, .low = 0x8000000000000000ULL},/* extended 0.5 */ + { .high = 0x4002, .low = 0xa000000000000000ULL},/* extended 10.0 */ }; #endif diff --git a/arch/arm/nwfpe/softfloat-specialize b/arch/arm/nwfpe/softfloat-specialize index acf4091..d4a4c8e 100644 --- a/arch/arm/nwfpe/softfloat-specialize +++ b/arch/arm/nwfpe/softfloat-specialize @@ -332,6 +332,7 @@ static floatx80 commonNaNToFloatx80( commonNaNT a ) z.low = LIT64( 0xC000000000000000 ) | ( a.high>>1 ); z.high = ( ( (bits16) a.sign )<<15 ) | 0x7FFF; + z.__padding = 0; return z; } diff --git a/arch/arm/nwfpe/softfloat.c b/arch/arm/nwfpe/softfloat.c index f9f0491..0f9656e 100644 --- a/arch/arm/nwfpe/softfloat.c +++ b/arch/arm/nwfpe/softfloat.c @@ -531,6 +531,7 @@ INLINE floatx80 packFloatx80( flag zSign, int32 zExp, bits64 zSig ) z.low = zSig; z.high = ( ( (bits16) zSign )<<15 ) + zExp; + z.__padding = 0; return z; } @@ -2831,6 +2832,7 @@ static floatx80 subFloatx80Sigs( struct roundingData *roundData, floatx80 a, flo roundData->exception |= float_flag_invalid; z.low = floatx80_default_nan_low; z.high = floatx80_default_nan_high; + z.__padding = 0; return z; } if ( aExp == 0 ) { @@ -2950,6 +2952,7 @@ floatx80 floatx80_mul( struct roundingData *roundData, floatx80 a, floatx80 b ) roundData->exception |= float_flag_invalid; z.low = floatx80_default_nan_low; z.high = floatx80_default_nan_high; + z.__padding = 0; return z; } return packFloatx80( zSign, 0x7FFF, LIT64( 0x8000000000000000 ) ); @@ -3015,6 +3018,7 @@ floatx80 floatx80_div( struct roundingData *roundData, floatx80 a, floatx80 b ) roundData->exception |= float_flag_invalid; z.low = floatx80_default_nan_low; z.high = floatx80_default_nan_high; + z.__padding = 0; return z; } roundData->exception |= float_flag_divbyzero; @@ -3093,6 +3097,7 @@ floatx80 floatx80_rem( struct roundingData *roundData, floatx80 a, floatx80 b ) roundData->exception |= float_flag_invalid; z.low = floatx80_default_nan_low; z.high = floatx80_default_nan_high; + z.__padding = 0; return z; } normalizeFloatx80Subnormal( bSig, &bExp, &bSig ); @@ -3184,6 +3189,7 @@ floatx80 floatx80_sqrt( struct roundingData *roundData, floatx80 a ) roundData->exception |= float_flag_invalid; z.low = floatx80_default_nan_low; z.high = floatx80_default_nan_high; + z.__padding = 0; return z; } if ( aExp == 0 ) { diff --git a/arch/arm/nwfpe/softfloat.h b/arch/arm/nwfpe/softfloat.h index 1415170..1301d97 100644 --- a/arch/arm/nwfpe/softfloat.h +++ b/arch/arm/nwfpe/softfloat.h @@ -55,6 +55,7 @@ typedef unsigned long int float32; typedef unsigned long long float64; typedef struct { unsigned short high; + unsigned short __padding; unsigned long long low; } floatx80; -- 2.7.4