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Line 2,942: − − === Register ACLs === − Falcon tracks permission metadata about each crypto reg. Permissions include read/write ability per execution mode, as well as ability to use the reg for encrypt/decrypt, among other permissions. Permissions are propagated when registers are referenced by instructions (e.g. moving a value from read-protected $cX to $cY will result in $cY also being read-protected). − − === Authenticated Mode Entry/Exit === − Entry to Authenticated Mode always sets $pc to the address supplied in $cauth (ie the base of the signature-checked region). This takes effect when trying to branch to any address within the range covered by $cauth. Entry to Authenticated Mode (also called "Secure Mode") computes a MAC over the $cauth region and compares it to $c6 in order to perform the signature check. − − Exit from Authenticated Mode must poke a special register before leaving authenticated code pages and a failure to do this would result in the Falcon core halting. Every Falcon based unit (TSEC, NVDEC, VIC) must map this register in their engine-specific subset of registers. In TSEC's case, the register is [[#TSEC_SCP_CTL_MODE|TSEC_SCP_CTL_MODE]]. − − === Unknown Instructions === − <code>00000000: f5 3c 00 e0 cchmod</code> - resets all crypto register's permissions. − − <code>00000000: f5 3c XY a8 c_unk $cY X</code> - unknown crypto operation. − − <code>00000000: f5 3c 0X 90 crng $cX</code> - seems to initialize a crypto register with random data. Line 2,932:
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new stuff
0x0020: xdst (with cxset) or cxsin (fuc5 opcode 0x88)
0x0020: xdst (with cxset) or cxsin (fuc5 opcode 0x88)
0x0030: xdld (with cxset) or cxsout (fuc5 opcode 0x8C)
0x0030: xdld (with cxset) or cxsout (fuc5 opcode 0x8C)
0x0040: csrng (fuc5 opcode 0x90)
0x0040: crng (fuc5 opcode 0x90)
0x0050: cs0begin (fuc5 opcode 0x94)
0x0050: cs0begin (fuc5 opcode 0x94)
0x0060: cs0exec (fuc5 opcode 0x98)
0x0060: cs0exec (fuc5 opcode 0x98)
0x0080: cs1exec (fuc5 opcode 0xA0)
0x0080: cs1exec (fuc5 opcode 0xA0)
0x0090: (fuc5 opcode 0xA4)
0x0090: (fuc5 opcode 0xA4)
0x00A0: (fuc5 opcode 0xA8)
0x00A0: cchmod (fuc5 opcode 0xA8)
0x00B0: cxor (fuc5 opcode 0xAC)
0x00B0: cxor (fuc5 opcode 0xAC)
0x00C0: cadd (fuc5 opcode 0xB0)
0x00C0: cadd (fuc5 opcode 0xB0)
0x0160: (fuc5 opcode 0xD8)
0x0160: (fuc5 opcode 0xD8)
0x0170: csigenc (fuc5 opcode 0xDC)
0x0170: csigenc (fuc5 opcode 0xDC)
0x0180: cchmod (fuc5 opcode 0xE0)
0x0180: csigclr (fuc5 opcode 0xE0)
|-
|-
| 31
| 31
load_keygen(key_buf, key_version, is_blob_dec);
load_keygen(key_buf, key_version, is_blob_dec);
// fuc5 crypt cchmod instruction
// fuc5 crypt csigclr instruction
// Resets the ACL bits
// Clears the cauth signature
csigclr();
// Clear all crypto registers
// Clear all crypto registers
cxor(c7, c7);
cxor(c7, c7);
// fuc5 crypt cchmod instruction
// fuc5 crypt csigclr instruction
// Resets the ACL bits
// Clears the cauth signature
csigclr();
// Jump to Payload
// Jump to Payload
== Notes ==
== Notes ==
[https://wiki.0x04.net/wiki/Marcin_Ko%C5%9Bcielnicki mwk] shared additional info learned from RE of falcon processors over the years, which hasn't made it into envytools documentation yet:
Part of the information here (which hasn't made it into envytools documentation yet) was shared by [https://wiki.0x04.net/wiki/Marcin_Ko%C5%9Bcielnicki mwk] from reverse engineering falcon processors over the years.
=== Register ACLs ===
Falcon tracks permission metadata about each crypto reg. Permissions include read/write ability per execution mode, as well as ability to use the reg for encrypt/decrypt, among other permissions. Permissions are propagated when registers are referenced by instructions (e.g. moving a value from read-protected $cX to $cY will result in $cY also being read-protected).
=== Authenticated Mode Entry/Exit ===
Entry to Authenticated Mode always sets $pc to the address supplied in $cauth (ie the base of the signature-checked region). This takes effect when trying to branch to any address within the range covered by $cauth. Entry to Authenticated Mode (also called "Secure Mode") computes a MAC over the $cauth region and compares it to $c6 in order to perform the signature check.
Exit from Authenticated Mode must poke a special register before leaving authenticated code pages and a failure to do this would result in the Falcon core halting. Every Falcon based unit (TSEC, NVDEC, VIC) must map this register in their engine-specific subset of registers. In TSEC's case, the register is [[#TSEC_SCP_CTL_MODE|TSEC_SCP_CTL_MODE]].
=== csigclr ===
<code>00000000: f5 3c 00 e0 csigclr</code>
This instruction takes no operands and appears to clear the saved cauth signature used by the csigenc instruction.
=== cchmod ===
<code>00000000: f5 3c XY a8 cchmod $cY 0X</code> or <code>00000000: f5 3c XY a9 cchmod $cY 1X</code>
This instruction takes a crypto register and a 5 bit immediate value. It appears to set the [[#Register ACLs|crypto registers' ACL]] bits as follows:
{| class="wikitable" border="1"
! Bits
! Description
|-
| 0
| Allow register to be used as key in NS or LS mode
|-
| 1
| Allow register to be used as key in HS mode
|-
| 2
| Set register as readable in NS or LS mode
|-
| 3
| Set register as readable in HS mode
|-
| 4
| Set register as writable in NS or LS mode
|}
=== crng ===
<code>00000000: f5 3c 0X 90 crng $cX</code>
This instruction takes no operands and appears to initialize a crypto register with random data.
=== cxset ===
=== cxset ===
For example, if override type=0b000, then the "length" argument to <code>xdst</code> is instead treated as the index of the target $cX register.
For example, if override type=0b000, then the "length" argument to <code>xdst</code> is instead treated as the index of the target $cX register.
=== Secrets ===
=== Secrets ===
| 0x05 || Used by nvhost_tsec, nvhost_nvdec_bl020_prod, nvhost_nvdec020_prod, nvhost_nvdec020_ns and acr_ucode firmwares.
| 0x05 || Used by nvhost_tsec, nvhost_nvdec_bl020_prod, nvhost_nvdec020_prod, nvhost_nvdec020_ns and acr_ucode firmwares.
|-
|-
| 0x07 || Used by nvhost_tsec firmware.
| 0x07 || Used by [6.0.0+] nvhost_tsec firmware.
|-
|-
| 0x09 || Used by nvhost_tsec firmware.
| 0x09 || Used by nvhost_tsec firmware.
| 0x0F || Used by nvhost_tsec firmware.
| 0x0F || Used by nvhost_tsec firmware.
|-
|-
| 0x15 || Used by nvhost_tsec, nvhost_nvdec_bl020_prod, [5.0.0+] nvhost_nvdec020_prod and nvhost_nvdec020_ns firmwares.
| 0x10 || Used by [1.0.0-5.1.0] nvhost_tsec firmware.
|-
| 0x15 || Used by nvhost_nvdec_bl020_prod, [5.0.0+] nvhost_nvdec020_prod, [5.0.0+] nvhost_nvdec020_ns and [6.0.0+] nvhost_tsec firmwares.
|-
|-
| 0x26 || Used by [[#KeygenLdr|KeygenLdr]].
| 0x26 || Used by [[#KeygenLdr|KeygenLdr]].