[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$

Corrections explained:
Prevent arithmetic overflow in OOB read operation
Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 nand-utils/nandflipbits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
index 7066408..ef663c6 100644
--- a/nand-utils/nandflipbits.c
+++ b/nand-utils/nandflipbits.c
@@ -251,7 +251,7 @@ int main(int argc, char **argv)
 			bufoffs += mtd.min_io_size;
 
 			ret = mtd_read_oob(mtd_desc, &mtd, fd,
-					   bit_to_flip->block * mtd.eb_size +
+					   (long long)bit_to_flip->block * (long long)mtd.eb_size +
 					   blkoffs,
 					   mtd.oob_size, buffer + bufoffs);
 			if (ret) {
-- 
2.30.2


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Re: [PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Zhihao Cheng]

在 2024/12/13 2:39, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$
> 
> Corrections explained:
> Prevent arithmetic overflow in OOB read operation
> Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   nand-utils/nandflipbits.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
> index 7066408..ef663c6 100644
> --- a/nand-utils/nandflipbits.c
> +++ b/nand-utils/nandflipbits.c
> @@ -251,7 +251,7 @@ int main(int argc, char **argv)
>   			bufoffs += mtd.min_io_size;
>   
>   			ret = mtd_read_oob(mtd_desc, &mtd, fd,
> -					   bit_to_flip->block * mtd.eb_size +
> +					   (long long)bit_to_flip->block * (long long)mtd.eb_size +

Hi Anton.
Type converting for 'bit_to_flip->block' is enough, and it could be 
better making the type as 'unsigned long long'.
>   					   blkoffs,
>   					   mtd.oob_size, buffer + bufoffs);
>   			if (ret) {
> 


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[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$

Corrections explained:
Prevent arithmetic overflow in OOB read operation
Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 nand-utils/nandflipbits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
index 7066408..ef663c6 100644
--- a/nand-utils/nandflipbits.c
+++ b/nand-utils/nandflipbits.c
@@ -251,7 +251,7 @@ int main(int argc, char **argv)
 			bufoffs += mtd.min_io_size;
 
 			ret = mtd_read_oob(mtd_desc, &mtd, fd,
-					   bit_to_flip->block * mtd.eb_size +
+					   (unsigned long long)bit_to_flip->block * (long long)mtd.eb_size +
 					   blkoffs,
 					   mtd.oob_size, buffer + bufoffs);
 			if (ret) {
-- 
2.30.2


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Re: [PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Zhihao Cheng]

在 2024/12/13 21:19, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$
> 
> Corrections explained:
> Prevent arithmetic overflow in OOB read operation
> Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   nand-utils/nandflipbits.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
> index 7066408..ef663c6 100644
> --- a/nand-utils/nandflipbits.c
> +++ b/nand-utils/nandflipbits.c
> @@ -251,7 +251,7 @@ int main(int argc, char **argv)
>   			bufoffs += mtd.min_io_size;
>   
>   			ret = mtd_read_oob(mtd_desc, &mtd, fd,
> -					   bit_to_flip->block * mtd.eb_size +
> +					   (unsigned long long)bit_to_flip->block * (long long)mtd.eb_size +

Hi, Anton. Change it like:
(unsigned long long)bit_to_flip->block * mtd.eb_size + blkoffs
>   					   blkoffs,
>   					   mtd.oob_size, buffer + bufoffs);
>   			if (ret) {
> 


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[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$

Corrections explained:
Prevent arithmetic overflow in OOB read operation
Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 nand-utils/nandflipbits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
index 7066408..ef663c6 100644
--- a/nand-utils/nandflipbits.c
+++ b/nand-utils/nandflipbits.c
@@ -251,7 +251,7 @@ int main(int argc, char **argv)
 			bufoffs += mtd.min_io_size;
 
 			ret = mtd_read_oob(mtd_desc, &mtd, fd,
-					   bit_to_flip->block * mtd.eb_size +
+					   (unsigned long long)bit_to_flip->block * mtd.eb_size +
 					   blkoffs,
 					   mtd.oob_size, buffer + bufoffs);
 			if (ret) {
-- 
2.30.2


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Re: [PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Zhihao Cheng]

在 2024/12/14 20:18, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'bit_to_flip->block * mtd.eb_size + blkoffs' is a subject to overflow because its operands are not cast to a larger data type before performing arith$
> 
> Corrections explained:
> Prevent arithmetic overflow in OOB read operation
> Resolved an issue where the calculation of the offset in the OOB read operation could overflow due to operands not being cast to a larger data type. Specifically, the multiplication of bi$
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   nand-utils/nandflipbits.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 

Reviewed-by: Zhihao Cheng <chengzhihao1@huawei.com>
> diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
> index 7066408..ef663c6 100644
> --- a/nand-utils/nandflipbits.c
> +++ b/nand-utils/nandflipbits.c
> @@ -251,7 +251,7 @@ int main(int argc, char **argv)
>   			bufoffs += mtd.min_io_size;
>   
>   			ret = mtd_read_oob(mtd_desc, &mtd, fd,
> -					   bit_to_flip->block * mtd.eb_size +
> +					   (unsigned long long)bit_to_flip->block * mtd.eb_size +
>   					   blkoffs,
>   					   mtd.oob_size, buffer + bufoffs);
>   			if (ret) {
> 


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[PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Anton Moryakov]

Report of the static analyzer:
The value of an arithmetic expression 'page * (mtd.min_io_size + mtd.oob_size)' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic

Corrections explained:
Casting bit_to_flip->block to unsigned long long expands the range of values ​​and allows the result of the multiplication to be calculated in a wider data type.
The arithmetic is performed in a safe range, preventing overflow.
Sum + blkoffs is now also safe, since the result of the expression is already calculated in unsigned long long.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>

---
 nand-utils/nandflipbits.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
index ef663c6..c4642fe 100644
--- a/nand-utils/nandflipbits.c
+++ b/nand-utils/nandflipbits.c
@@ -213,7 +213,7 @@ int main(int argc, char **argv)
 		bits_to_flip[i].block = bits_to_flip[i].offset / blklen;
 		bits_to_flip[i].offset %= blklen;
 		page = bits_to_flip[i].offset / pagelen;
-		bits_to_flip[i].offset = (page *
+		bits_to_flip[i].offset = ((unsigned long long)page *
 					  (mtd.min_io_size + mtd.oob_size)) +
 					 (bits_to_flip[i].offset % pagelen);
 	}
-- 
2.30.2


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Re: [PATCH mtd-utils] nand-utils: Fix integer overflow in nandflipbits.c

[Zhihao Cheng]

在 2024/12/18 0:36, Anton Moryakov 写道:
> Report of the static analyzer:
> The value of an arithmetic expression 'page * (mtd.min_io_size + mtd.oob_size)' is a subject to overflow because its operands are not cast to a larger data type before performing arithmetic
> 
> Corrections explained:
> Casting bit_to_flip->block to unsigned long long expands the range of values ​​and allows the result of the multiplication to be calculated in a wider data type.
> The arithmetic is performed in a safe range, preventing overflow.
> Sum + blkoffs is now also safe, since the result of the expression is already calculated in unsigned long long.
> 
> Triggers found by static analyzer Svace.
> 
> Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
> 
> ---
>   nand-utils/nandflipbits.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/nand-utils/nandflipbits.c b/nand-utils/nandflipbits.c
> index ef663c6..c4642fe 100644
> --- a/nand-utils/nandflipbits.c
> +++ b/nand-utils/nandflipbits.c
> @@ -213,7 +213,7 @@ int main(int argc, char **argv)
>   		bits_to_flip[i].block = bits_to_flip[i].offset / blklen;
>   		bits_to_flip[i].offset %= blklen;
>   		page = bits_to_flip[i].offset / pagelen;
> -		bits_to_flip[i].offset = (page *
> +		bits_to_flip[i].offset = ((unsigned long long)page *
>   					  (mtd.min_io_size + mtd.oob_size)) +
>   					 (bits_to_flip[i].offset % pagelen);

I think the 'bits_to_flip[i].offset' is limited smaller than 
'mtd.eb_size' by the code:
  bits_to_flip[i].offset %= blklen;
  page = bits_to_flip[i].offset / pagelen;
So, I don't think an overflow could happen here.
>   	}
> 


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