[v1] ShellPkg/Type.c: Add value check before (LoopVar - 1)

[edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)

Posted by Gao, Zhichao 4 years, 9 months ago

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1964

If the file begin with single line Feed ('\n'), then
"AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r'"
would cause a underflow. Add this condition
"(AsciiChar == '\n' && LoopVar == 0)" before it to make sure
(LoopVar - 1) would never encounter a underflow.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Andrew Fish <afish@apple.com>
Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
---
 ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
index 4efc0a8e24..c1f670c713 100644
--- a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
+++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
@@ -78,12 +78,13 @@ TypeFileByHandle (
           // Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
           // characters to be displayed as is.
           //
-          if (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r') {
+          if ((AsciiChar == '\n' && LoopVar == 0) ||
+              (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r')) {
             //
-            // In case Line Feed (0xA) is encountered & Carriage Return (0xD)
-            // was not the previous character, print CR and LF. This is because
-            // Shell 2.0 requires carriage return with line feed for displaying
-            // each new line from left.
+            // In case file begin with single line Feed or Line Feed (0xA) is
+            // encountered & Carriage Return (0xD) was not previous character,
+            // print CR and LF. This is because Shell 2.0 requires carriage
+            // return Swith line feed for displaying each new line from left.
             //
             ShellPrintEx (-1, -1, L"\r\n");
             continue;
-- 
2.21.0.windows.1


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Re: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)

Posted by Jim Dailey 4 years, 9 months ago

Zhichao,

I believe the same problem exists further into the function in the 'else'
clause handling UCS2 characters.

Regards,
Jim

-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Gao, Zhichao
Sent: Monday, July 15, 2019 2:30 AM
To: devel@edk2.groups.io
Cc: Jaben Carsey; Ray Ni; Andrew Fish
Subject: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)


[EXTERNAL EMAIL] 

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1964

If the file begin with single line Feed ('\n'), then
"AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r'"
would cause a underflow. Add this condition
"(AsciiChar == '\n' && LoopVar == 0)" before it to make sure
(LoopVar - 1) would never encounter a underflow.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Andrew Fish <afish@apple.com>
Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
---
 ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
index 4efc0a8e24..c1f670c713 100644
--- a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
+++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
@@ -78,12 +78,13 @@ TypeFileByHandle (
           // Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
           // characters to be displayed as is.
           //
-          if (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r') {
+          if ((AsciiChar == '\n' && LoopVar == 0) ||
+              (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r')) {
             //
-            // In case Line Feed (0xA) is encountered & Carriage Return (0xD)
-            // was not the previous character, print CR and LF. This is because
-            // Shell 2.0 requires carriage return with line feed for displaying
-            // each new line from left.
+            // In case file begin with single line Feed or Line Feed (0xA) is
+            // encountered & Carriage Return (0xD) was not previous character,
+            // print CR and LF. This is because Shell 2.0 requires carriage
+            // return Swith line feed for displaying each new line from left.
             //
             ShellPrintEx (-1, -1, L"\r\n");
             continue;
-- 
2.21.0.windows.1




Dell Corporation Limited is registered in England and Wales. Company Registration Number: 2081369
Registered address: Dell House, The Boulevard, Cain Road, Bracknell,  Berkshire, RG12 1LF, UK.
Company details for other Dell UK entities can be found on  www.dell.co.uk.


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Re: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)

Posted by Gao, Zhichao 4 years, 9 months ago

You are right. I missed the USC2 section. I would update that in next version.

Thanks,
Zhichao

> -----Original Message-----
> From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of
> Jim Dailey
> Sent: Monday, July 15, 2019 9:09 PM
> To: Gao, Zhichao <zhichao.gao@intel.com>
> Cc: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ray <ray.ni@intel.com>;
> afish@apple.com; devel@edk2.groups.io
> Subject: Re: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before
> (LoopVar - 1)
> 
> Zhichao,
> 
> I believe the same problem exists further into the function in the 'else'
> clause handling UCS2 characters.
> 
> Regards,
> Jim
> 
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Gao,
> Zhichao
> Sent: Monday, July 15, 2019 2:30 AM
> To: devel@edk2.groups.io
> Cc: Jaben Carsey; Ray Ni; Andrew Fish
> Subject: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before
> (LoopVar - 1)
> 
> 
> [EXTERNAL EMAIL]
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1964
> 
> If the file begin with single line Feed ('\n'), then "AsciiChar == '\n' &&
> ((CHAR8*)Buffer)[LoopVar-1] != '\r'"
> would cause a underflow. Add this condition "(AsciiChar == '\n' && LoopVar
> == 0)" before it to make sure (LoopVar - 1) would never encounter a
> underflow.
> 
> Cc: Jaben Carsey <jaben.carsey@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Andrew Fish <afish@apple.com>
> Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
> ---
>  ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> index 4efc0a8e24..c1f670c713 100644
> --- a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> +++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> @@ -78,12 +78,13 @@ TypeFileByHandle (
>            // Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
>            // characters to be displayed as is.
>            //
> -          if (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r') {
> +          if ((AsciiChar == '\n' && LoopVar == 0) ||
> +              (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] !=
> + '\r')) {
>              //
> -            // In case Line Feed (0xA) is encountered & Carriage Return (0xD)
> -            // was not the previous character, print CR and LF. This is because
> -            // Shell 2.0 requires carriage return with line feed for displaying
> -            // each new line from left.
> +            // In case file begin with single line Feed or Line Feed (0xA) is
> +            // encountered & Carriage Return (0xD) was not previous character,
> +            // print CR and LF. This is because Shell 2.0 requires carriage
> +            // return Swith line feed for displaying each new line from left.
>              //
>              ShellPrintEx (-1, -1, L"\r\n");
>              continue;
> --
> 2.21.0.windows.1
> 
> 
> 
> 
> Dell Corporation Limited is registered in England and Wales. Company
> Registration Number: 2081369
> Registered address: Dell House, The Boulevard, Cain Road, Bracknell,
> Berkshire, RG12 1LF, UK.
> Company details for other Dell UK entities can be found on  www.dell.co.uk.
> 
> 
> 


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Re: [edk2-devel] [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)

Posted by Carsey, Jaben 4 years, 9 months ago

Please remove the typo (there is an extra S after 'return'). This line:
// return Swith line feed for displaying each new line from left.


> -----Original Message-----
> From: Gao, Zhichao
> Sent: Monday, July 15, 2019 12:30 AM
> To: devel@edk2.groups.io
> Cc: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ray <ray.ni@intel.com>;
> Andrew Fish <afish@apple.com>
> Subject: [PATCH] ShellPkg/Type.c: Add value check before (LoopVar - 1)
> 
> REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1964
> 
> If the file begin with single line Feed ('\n'), then
> "AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r'"
> would cause a underflow. Add this condition
> "(AsciiChar == '\n' && LoopVar == 0)" before it to make sure
> (LoopVar - 1) would never encounter a underflow.
> 
> Cc: Jaben Carsey <jaben.carsey@intel.com>
> Cc: Ray Ni <ray.ni@intel.com>
> Cc: Andrew Fish <afish@apple.com>
> Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
> ---
>  ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
> 
> diff --git a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> index 4efc0a8e24..c1f670c713 100644
> --- a/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> +++ b/ShellPkg/Library/UefiShellLevel3CommandsLib/Type.c
> @@ -78,12 +78,13 @@ TypeFileByHandle (
>            // Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
>            // characters to be displayed as is.
>            //
> -          if (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r') {
> +          if ((AsciiChar == '\n' && LoopVar == 0) ||
> +              (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r')) {
>              //
> -            // In case Line Feed (0xA) is encountered & Carriage Return (0xD)
> -            // was not the previous character, print CR and LF. This is because
> -            // Shell 2.0 requires carriage return with line feed for displaying
> -            // each new line from left.
> +            // In case file begin with single line Feed or Line Feed (0xA) is
> +            // encountered & Carriage Return (0xD) was not previous character,
> +            // print CR and LF. This is because Shell 2.0 requires carriage
> +            // return Swith line feed for displaying each new line from left.
>              //
>              ShellPrintEx (-1, -1, L"\r\n");
>              continue;
> --
> 2.21.0.windows.1


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