TCTI: Separate namespaces for internal struct #2843

AndreasFuchsTPM · 2024-05-17T08:03:49Z

Some (dynamic) linkers seam to resolve internal symbols against the loading library in a dlopen() instead of its local symbols. Namely a tss2_tcti_info symbol ref of e.g. tcti-device would resolve against the symbol of tctildr.
We protect against such situations by separating the names.

Fixes: #2840

SoapGentoo · 2024-05-18T12:59:41Z

src/tss2-tcti/tcti-cmd.c

@@ -622,7 +622,7 @@ TSS2_RC Tss2_Tcti_Cmd_Init (TSS2_TCTI_CONTEXT *tctiContext, size_t *size,
 }

 /* public info structure */
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_cmd_info = {


@AndreasFuchsTPM any reason not to make these static too, just to reduce the incidence of these?

SoapGentoo · 2024-05-18T13:03:32Z

src/tss2-tcti/tcti-i2c-helper.c

@@ -846,7 +846,7 @@ TSS2_RC Tss2_Tcti_I2c_Helper_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size
    return TSS2_RC_SUCCESS;
 }

-static const TSS2_TCTI_INFO tss2_tcti_info = {
+static const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {


@AndreasFuchsTPM why is this one static, but the other ones aren't?

AndreasFuchsTPM · 2024-05-23T11:17:26Z

AFAIR, the static qualifier does not change anything for global variables.
My understanding is:
static functions -> only visible inside local file
static (function) variables -> become global variables but under the namespace of the function
static (global) variables -> are global variables anyways, so no change given static

See also

If I move the info into the getInfo function:

That's at least, what GCC does.

My take away was always: the static keyword is misleading for global variables and thus should be omitted.

So yes, I'll get rid of these...

Some (dynamic) linkers seam to resolve internal symbols against the loading library in a dlopen() instead of its local symbols. Namely a tss2_tcti_info symbol ref of e.g. tcti-device would resolve against the symbol of tctildr. We protect against such situations by separating the names. Signed-off-by: Andreas Fuchs <[email protected]>

SoapGentoo · 2024-05-23T12:59:38Z

diff -u <(echo 'const int x = 0;' | gcc -c -xc - -o non-static.o && readelf -a non-static.o) <(echo 'static const int x = 0;' | gcc -c -xc - -o static.o && readelf -a static.o)
--- /dev/fd/63
+++ /dev/fd/62
@@ -39,7 +39,7 @@
   [ 7] .note.gnu.pr[...] NOTE             0000000000000000  00000078
        0000000000000050  0000000000000000   A       0     0     8
   [ 8] .symtab           SYMTAB           0000000000000000  000000c8
-       0000000000000048  0000000000000018           9     2     8
+       0000000000000048  0000000000000018           9     3     8
   [ 9] .strtab           STRTAB           0000000000000000  00000110
        000000000000000b  0000000000000000           0     0     1
   [10] .shstrtab         STRTAB           0000000000000000  0000011b
@@ -63,7 +63,7 @@
    Num:    Value          Size Type    Bind   Vis      Ndx Name
      0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND 
      1: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS <stdin>
-     2: 0000000000000000     4 OBJECT  GLOBAL DEFAULT    4 x
+     2: 0000000000000000     4 OBJECT  LOCAL  DEFAULT    4 x
 
 No version information found in this file.

static on global variables makes the linkage internal, which means less leaking of internal symbols, which in general is a good thing. I doubt this bug would have occurred if all instances of TSS2_TCTI_INFO objects would have been static in their respective files.

Final piece of why you should always use static when possible: https://godbolt.org/z/v1z14Ka1W
static global variables do not go through the GOT when compiled with -fPIC, this avoids a pointless indirection if you plan to keep the variable private anyhow.

SoapGentoo · 2024-05-23T13:15:54Z

src/tss2-tcti/tcti-cmd.c

@@ -622,7 +622,7 @@ TSS2_RC Tss2_Tcti_Cmd_Init (TSS2_TCTI_CONTEXT *tctiContext, size_t *size,
 }

 /* public info structure */
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_cmd_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_cmd_info = {

static const TSS2_TCTI_INFO tss2_tcti_cmd_info = {

SoapGentoo · 2024-05-23T13:16:02Z

src/tss2-tcti/tcti-device.c

@@ -530,7 +530,7 @@ Tss2_Tcti_Device_Init (
    return TSS2_RC_SUCCESS;
 }

-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_device_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_device_info = {

static const TSS2_TCTI_INFO tss2_tcti_device_info = {

SoapGentoo · 2024-05-23T13:16:09Z

src/tss2-tcti/tcti-i2c-ftdi.c

@@ -280,7 +280,7 @@ Tss2_Tcti_I2c_Ftdi_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size, const ch
    return Tss2_Tcti_I2c_Helper_Init (tcti_context, size, &tcti_platform);
 }

-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_i2c_ftdi_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_i2c_ftdi_info = {

static const TSS2_TCTI_INFO tss2_tcti_i2c_ftdi_info = {

SoapGentoo · 2024-05-23T13:16:15Z

src/tss2-tcti/tcti-i2c-helper.c

@@ -846,7 +846,7 @@ TSS2_RC Tss2_Tcti_I2c_Helper_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size
    return TSS2_RC_SUCCESS;
 }

-static const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {

static const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {

SoapGentoo · 2024-05-23T13:16:22Z

src/tss2-tcti/tcti-libtpms.c

@@ -880,7 +880,7 @@ Tss2_Tcti_Libtpms_Init(
 }

 /* public info structure */
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_libtpms_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_libtpms_info = {

static const TSS2_TCTI_INFO tss2_tcti_libtpms_info = {

SoapGentoo · 2024-05-23T13:17:08Z

src/tss2-tcti/tcti-spidev.c

@@ -197,7 +197,7 @@ Tss2_Tcti_Spidev_Init (TSS2_TCTI_CONTEXT* tcti_context, size_t* size, const char
    return Tss2_Tcti_Spi_Helper_Init (tcti_context, size, &platform);
 }

-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_spidev_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_spidev_info = {

static const TSS2_TCTI_INFO tss2_tcti_spidev_info = {

SoapGentoo · 2024-05-23T13:17:13Z

src/tss2-tcti/tcti-swtpm.c

@@ -639,7 +639,7 @@ Tss2_Tcti_Swtpm_Init (
 }

 /* public info structure */
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_swtpm_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_swtpm_info = {

static const TSS2_TCTI_INFO tss2_tcti_swtpm_info = {

SoapGentoo · 2024-05-23T13:17:20Z

src/tss2-tcti/tcti-tbs.c

@@ -315,7 +315,7 @@ Tss2_Tcti_Tbs_Init (
    return TSS2_RC_SUCCESS;
 }

-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_tbs_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_tbs_info = {

static const TSS2_TCTI_INFO tss2_tcti_tbs_info = {

SoapGentoo · 2024-05-23T13:17:30Z

src/tss2-tcti/tctildr.c

@@ -587,7 +587,7 @@ TSS2_RC Tss2_Tcti_TctiLdr_Init (TSS2_TCTI_CONTEXT *tctiContext, size_t *size,
 }

 __attribute__((weak))
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tctildr_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tctildr_info = {

static const TSS2_TCTI_INFO tss2_tctildr_info = {

SoapGentoo · 2024-05-23T13:17:37Z

test/fuzz/tcti/tcti-fuzzing.c

@@ -265,7 +265,7 @@ Tss2_Tcti_Fuzzing_Init (
 }

 /* public info structure */
-const TSS2_TCTI_INFO tss2_tcti_info = {
+const TSS2_TCTI_INFO tss2_tcti_fuzzing_info = {


Suggested change

const TSS2_TCTI_INFO tss2_tcti_fuzzing_info = {

static const TSS2_TCTI_INFO tss2_tcti_fuzzing_info = {

SoapGentoo · 2024-05-29T21:59:44Z

@AndreasFuchsTPM ping

SoapGentoo · 2024-09-30T10:07:35Z

@AndreasFuchsTPM any movement here?

AndreasFuchsTPM added the backport Issues to be backported to old-stable label May 17, 2024

AndreasFuchsTPM added this to the 4.2.0 milestone May 17, 2024

joholl previously approved these changes May 17, 2024

View reviewed changes

SoapGentoo reviewed May 18, 2024

View reviewed changes

AndreasFuchsTPM dismissed joholl’s stale review via b1d63ca May 23, 2024 11:20

AndreasFuchsTPM force-pushed the fix_namecollision branch from a3c0f8c to b1d63ca Compare May 23, 2024 11:20

AndreasFuchsTPM requested a review from SoapGentoo May 23, 2024 11:20

SoapGentoo suggested changes May 23, 2024

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TCTI: Separate namespaces for internal struct #2843

TCTI: Separate namespaces for internal struct #2843

AndreasFuchsTPM commented May 17, 2024

SoapGentoo May 18, 2024

SoapGentoo May 18, 2024

AndreasFuchsTPM commented May 23, 2024

SoapGentoo commented May 23, 2024 •

edited

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SoapGentoo commented May 29, 2024

SoapGentoo commented Sep 30, 2024

	const TSS2_TCTI_INFO tss2_tcti_cmd_info = {
	static const TSS2_TCTI_INFO tss2_tcti_cmd_info = {

	const TSS2_TCTI_INFO tss2_tcti_device_info = {
	static const TSS2_TCTI_INFO tss2_tcti_device_info = {

	const TSS2_TCTI_INFO tss2_tcti_i2c_ftdi_info = {
	static const TSS2_TCTI_INFO tss2_tcti_i2c_ftdi_info = {

	const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {
	static const TSS2_TCTI_INFO tss2_tcti_i2c_helper_info = {

	const TSS2_TCTI_INFO tss2_tcti_libtpms_info = {
	static const TSS2_TCTI_INFO tss2_tcti_libtpms_info = {

	const TSS2_TCTI_INFO tss2_tcti_spidev_info = {
	static const TSS2_TCTI_INFO tss2_tcti_spidev_info = {

	const TSS2_TCTI_INFO tss2_tcti_swtpm_info = {
	static const TSS2_TCTI_INFO tss2_tcti_swtpm_info = {

	const TSS2_TCTI_INFO tss2_tcti_tbs_info = {
	static const TSS2_TCTI_INFO tss2_tcti_tbs_info = {

	const TSS2_TCTI_INFO tss2_tctildr_info = {
	static const TSS2_TCTI_INFO tss2_tctildr_info = {

	const TSS2_TCTI_INFO tss2_tcti_fuzzing_info = {
	static const TSS2_TCTI_INFO tss2_tcti_fuzzing_info = {

TCTI: Separate namespaces for internal struct #2843

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TCTI: Separate namespaces for internal struct #2843

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AndreasFuchsTPM commented May 17, 2024

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SoapGentoo commented May 23, 2024 • edited Loading

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SoapGentoo commented May 29, 2024

SoapGentoo commented Sep 30, 2024

SoapGentoo commented May 23, 2024 •

edited

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