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[NTOS:KDBG] Enhance the 'tss' command.

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We allow specifying manually the TSS selector number or its descriptor address,
and dump more information from the associated KTSS structure.

Also add the KdbpRetrieveTss() helper to retrieve the PKTSS from its
corresponding selector number. It will also be useful for future improvements.
This commit is contained in:
Hermès Bélusca-Maïto 2019-11-03 03:44:55 +01:00
parent dc0c721ff8
commit 8826ee8ff7
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GPG key ID: 3B2539C65E7B93D0
1 changed files with 133 additions and 12 deletions
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145
ntoskrnl/kdbg/kdb_cli.c
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@ -178,7 +178,7 @@ static const struct
{ "ldt", "ldt", "Display the local descriptor table.", KdbpCmdGdtLdtIdt },
{ "idt", "idt", "Display the interrupt descriptor table.", KdbpCmdGdtLdtIdt },
{ "pcr", "pcr", "Display the processor control region.", KdbpCmdPcr },
{ "tss", "tss", "Display a task state segment.", KdbpCmdTss },
{ "tss", "tss [selector|*descaddr]", "Display the current task state segment, or the one specified by its selector number or descriptor address.", KdbpCmdTss },
/* Others */
{ NULL, NULL, "Others", NULL },
@ -987,6 +987,52 @@ KdbpCmdRegs(
return TRUE;
}
static PKTSS
KdbpRetrieveTss(
IN USHORT TssSelector,
OUT PULONG pType OPTIONAL,
IN PKDESCRIPTOR pGdtr OPTIONAL)
{
KDESCRIPTOR Gdtr;
KGDTENTRY Desc;
PKTSS Tss;
/* Retrieve the Global Descriptor Table (user-provided or system) */
if (pGdtr)
Gdtr = *pGdtr;
else
Ke386GetGlobalDescriptorTable(&Gdtr.Limit);
/* Check limits */
if ((TssSelector & (sizeof(KGDTENTRY) - 1)) ||
(TssSelector < sizeof(KGDTENTRY)) ||
(TssSelector + sizeof(KGDTENTRY) - 1 > Gdtr.Limit))
{
return NULL;
}
/* Retrieve the descriptor */
if (!NT_SUCCESS(KdbpSafeReadMemory(&Desc,
(PVOID)(Gdtr.Base + TssSelector),
sizeof(KGDTENTRY))))
{
return NULL;
}
/* Check for TSS32(Avl) or TSS32(Busy) */
if (Desc.HighWord.Bits.Type != 9 && Desc.HighWord.Bits.Type != 11)
{
return NULL;
}
if (pType) *pType = Desc.HighWord.Bits.Type;
Tss = (PKTSS)(ULONG_PTR)(Desc.BaseLow |
Desc.HighWord.Bytes.BaseMid << 16 |
Desc.HighWord.Bytes.BaseHi << 24);
return Tss;
}
static BOOLEAN
KdbpTrapFrameFromPrevTss(
PKTRAP_FRAME TrapFrame)
@ -2164,18 +2210,93 @@ KdbpCmdTss(
ULONG Argc,
PCHAR Argv[])
{
KTSS *Tss = KeGetPcr()->TSS;
USHORT TssSelector;
PKTSS Tss = NULL;
KdbpPrint("Current TSS is at 0x%p.\n", Tss);
KdbpPrint(" Eip: 0x%08x\n"
" Es: 0x%04x\n"
" Cs: 0x%04x\n"
" Ss: 0x%04x\n"
" Ds: 0x%04x\n"
" Fs: 0x%04x\n"
" Gs: 0x%04x\n"
" IoMapBase: 0x%04x\n",
Tss->Eip, Tss->Es, Tss->Cs, Tss->Ds, Tss->Fs, Tss->Gs, Tss->IoMapBase);
if (Argc >= 2)
{
/*
* Specified TSS via its selector [selector] or descriptor address [*descaddr].
* Note that we ignore any other argument values.
*/
PCHAR Param, pszNext;
ULONG ulValue;
Param = Argv[1];
if (Argv[1][0] == '*')
++Param;
ulValue = strtoul(Param, &pszNext, 0);
if (pszNext && *pszNext)
{
KdbpPrint("Invalid TSS specification.\n");
return TRUE;
}
if (Argv[1][0] == '*')
{
/* Descriptor specified */
TssSelector = 0; // Unknown selector!
// TODO: Room for improvement: Find the TSS descriptor
// in the GDT so as to validate it.
Tss = (PKTSS)(ULONG_PTR)ulValue;
if (!Tss)
{
KdbpPrint("Invalid 32-bit TSS descriptor.\n");
return TRUE;
}
}
else
{
/* Selector specified, retrive the corresponding TSS */
TssSelector = (USHORT)ulValue;
Tss = KdbpRetrieveTss(TssSelector, NULL, NULL);
if (!Tss)
{
KdbpPrint("Invalid 32-bit TSS selector.\n");
return TRUE;
}
}
}
if (!Tss)
{
/* If no TSS was specified, use the current TSS descriptor */
TssSelector = Ke386GetTr();
Tss = KeGetPcr()->TSS;
// NOTE: If everything works OK, Tss is the current TSS corresponding to the TR selector.
}
KdbpPrint("%s TSS 0x%04x is at 0x%p.\n",
(Tss == KeGetPcr()->TSS) ? "Current" : "Specified", TssSelector, Tss);
KdbpPrint(" Backlink: 0x%04x\n"
" Ss0:Esp0: 0x%04x:0x%08x\n"
// NOTE: Ss1:Esp1 and Ss2:Esp2: are in the NotUsed1 field.
" CR3: 0x%08x\n"
" EFlags: 0x%08x\n"
" Eax: 0x%08x\n"
" Ebx: 0x%08x\n"
" Ecx: 0x%08x\n"
" Edx: 0x%08x\n"
" Esi: 0x%08x\n"
" Edi: 0x%08x\n"
" Eip: 0x%08x\n"
" Esp: 0x%08x\n"
" Ebp: 0x%08x\n"
" Cs: 0x%04x\n"
" Ss: 0x%04x\n"
" Ds: 0x%04x\n"
" Es: 0x%04x\n"
" Fs: 0x%04x\n"
" Gs: 0x%04x\n"
" LDT: 0x%04x\n"
" Flags: 0x%04x\n"
" IoMapBase: 0x%04x\n",
Tss->Backlink, Tss->Ss0, Tss->Esp0, Tss->CR3, Tss->EFlags,
Tss->Eax, Tss->Ebx, Tss->Ecx, Tss->Edx, Tss->Esi, Tss->Edi,
Tss->Eip, Tss->Esp, Tss->Ebp,
Tss->Cs, Tss->Ss, Tss->Ds, Tss->Es, Tss->Fs, Tss->Gs,
Tss->LDT, Tss->Flags, Tss->IoMapBase);
return TRUE;
}