[edk2-devel] [PATCH v1 1/6] ShellPkg: acpiview: Allow passing buffer length to DumpGasStruct()

[Krzysztof Koch]

Modify the signature of the DumpGasStruct() function to include the
buffer length parameter and to return the number of bytes parsed by
the function.

This way it becomes possible to prevent buffer overruns when dumping
Generic Address Structure's (GAS) fields in the acpiview table
parsers.

Update all existing DumpGasStruct() calls in acpiview to add the
length argument.

Signed-off-by: Krzysztof Koch <krzysztof.koch at arm.com>
---

Notes:
    v1:
    - Modify DumpGasStruct() signature [Krzysztof]

 ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c              | 26 +++++++++++---------
 ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h              |  8 ++++--
 ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c |  2 +-
 3 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
index 8b3153516d2b7d9b920ab2de0344c17798ac572c..2d6ff80e299eebe7853061d3db89332197c0dc0e 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.c
@@ -589,23 +589,27 @@ STATIC CONST ACPI_PARSER GasParser[] = {
 
   @param [in] Ptr     Pointer to the start of the buffer.
   @param [in] Indent  Number of spaces to indent the output.
+  @param [in] Length  Length of the GAS structure buffer.
+
+  @retval Number of bytes parsed.
 **/
-VOID
+UINT32
 EFIAPI
 DumpGasStruct (
   IN UINT8*        Ptr,
-  IN UINT32        Indent
+  IN UINT32        Indent,
+  IN UINT32        Length
   )
 {
   Print (L"\n");
-  ParseAcpi (
-    TRUE,
-    Indent,
-    NULL,
-    Ptr,
-    GAS_LENGTH,
-    PARSER_PARAMS (GasParser)
-    );
+  return ParseAcpi (
+           TRUE,
+           Indent,
+           NULL,
+           Ptr,
+           Length,
+           PARSER_PARAMS (GasParser)
+           );
 }
 
 /**
@@ -621,7 +625,7 @@ DumpGas (
   IN UINT8*        Ptr
   )
 {
-  DumpGasStruct (Ptr, 2);
+  DumpGasStruct (Ptr, 2, GAS_LENGTH);
 }
 
 /**
diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
index 7657892d9fd2e2e14c6578611ff0cf1b6f6cd750..20ca358bddfa5953bfb1d1bebaebbf3079eaba01 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/AcpiParser.h
@@ -405,12 +405,16 @@ ParseAcpi (
 
   @param [in] Ptr     Pointer to the start of the buffer.
   @param [in] Indent  Number of spaces to indent the output.
+  @param [in] Length  Length of the GAS structure buffer.
+
+  @retval Number of bytes parsed.
 **/
-VOID
+UINT32
 EFIAPI
 DumpGasStruct (
   IN UINT8*        Ptr,
-  IN UINT32        Indent
+  IN UINT32        Indent,
+  IN UINT32        Length
   );
 
 /**
diff --git a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c
index 8de5ebf74775bab8e765849cba6ef4eb6f659a5a..2c47a3f848aa2dd512c53343ecf1c3c285173dd6 100644
--- a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c
+++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c
@@ -164,7 +164,7 @@ DumpDbgDeviceInfo (
   AddrSize = (UINT32*)(Ptr + (*AddrSizeOffset));
   while (Index < (*GasCount)) {
     PrintFieldName (4, L"BaseAddressRegister");
-    DumpGasStruct (DataPtr, 4);
+    DumpGasStruct (DataPtr, 4, *DbgDevInfoLen);
     PrintFieldName (4, L"Address Size");
     Print (L"0x%x\n", AddrSize[Index]);
     DataPtr += GAS_LENGTH;
--
'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'



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