diff mbox

bios-tables-test: handle false-positive smbios signature matches

Message ID 1427826740-22687-1-git-send-email-somlo@cmu.edu
State New
Headers show

Commit Message

Gabriel L. Somlo March 31, 2015, 6:32 p.m. UTC 
Rather than stopping at the first match for the SMBIOS signature
("_SM_") in the f-segment (0xF0000-0xFFFFF), continue scanning
until either a valid entry point table is found, or the f-segment
has been exhausted.

Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
---
 tests/bios-tables-test.c | 76 ++++++++++++++++++++++++++++--------------------
 1 file changed, 44 insertions(+), 32 deletions(-)

Comments

Bruce Rogers March 31, 2015, 7:19 p.m. UTC | #1 
>>> On 3/31/2015 at 12:32 PM, "Gabriel L. Somlo" <somlo@cmu.edu> wrote: 
> Rather than stopping at the first match for the SMBIOS signature
> ("_SM_") in the f-segment (0xF0000-0xFFFFF), continue scanning
> until either a valid entry point table is found, or the f-segment
> has been exhausted.
> 
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> ---
>  tests/bios-tables-test.c | 76 ++++++++++++++++++++++++++++--------------------
>  1 file changed, 44 insertions(+), 32 deletions(-)
> 
> diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
> index 735ac61..f79d89a 100644
> --- a/tests/bios-tables-test.c
> +++ b/tests/bios-tables-test.c
> @@ -599,35 +599,15 @@ static void test_acpi_asl(test_data *data)
>      free_test_data(&exp_data);
>  }
>  
> -static void test_smbios_ep_address(test_data *data)
> -{
> -    uint32_t off;
> -
> -    /* find smbios entry point structure */
> -    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> -        uint8_t sig[] = "_SM_";
> -        int i;
> -
> -        for (i = 0; i < sizeof sig - 1; ++i) {
> -            sig[i] = readb(off + i);
> -        }
> -
> -        if (!memcmp(sig, "_SM_", sizeof sig)) {
> -            break;
> -        }
> -    }
> -
> -    g_assert_cmphex(off, <, 0x100000);
> -    data->smbios_ep_addr = off;
> -}
> -
> -static void test_smbios_ep_table(test_data *data)
> +static bool smbios_ep_table_ok(test_data *data)
>  {
>      struct smbios_entry_point *ep_table = &data->smbios_ep_table;
>      uint32_t addr = data->smbios_ep_addr;
>  
>      ACPI_READ_ARRAY(ep_table->anchor_string, addr);
> -    g_assert(!memcmp(ep_table->anchor_string, "_SM_", 4));
> +    if (memcmp(ep_table->anchor_string, "_SM_", 4)) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->checksum, addr);
>      ACPI_READ_FIELD(ep_table->length, addr);
>      ACPI_READ_FIELD(ep_table->smbios_major_version, addr);
> @@ -636,17 +616,50 @@ static void test_smbios_ep_table(test_data *data)
>      ACPI_READ_FIELD(ep_table->entry_point_revision, addr);
>      ACPI_READ_ARRAY(ep_table->formatted_area, addr);
>      ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr);
> -    g_assert(!memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5));
> +    if (memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->intermediate_checksum, addr);
>      ACPI_READ_FIELD(ep_table->structure_table_length, addr);
> -    g_assert_cmpuint(ep_table->structure_table_length, >, 0);
> +    if (ep_table->structure_table_length == 0) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->structure_table_address, addr);
>      ACPI_READ_FIELD(ep_table->number_of_structures, addr);
> -    g_assert_cmpuint(ep_table->number_of_structures, >, 0);
> +    if (ep_table->number_of_structures == 0) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr);
> -    g_assert(!acpi_checksum((uint8_t *)ep_table, sizeof *ep_table));
> -    g_assert(!acpi_checksum((uint8_t *)ep_table + 0x10,
> -                            sizeof *ep_table - 0x10));
> +    if (acpi_checksum((uint8_t *)ep_table, sizeof *ep_table) ||
> +        acpi_checksum((uint8_t *)ep_table + 0x10, sizeof *ep_table - 0x10)) 
> {
> +        return false;
> +    }
> +    return true;
> +}
> +
> +static void test_smbios_entry_point(test_data *data)
> +{
> +    uint32_t off;
> +
> +    /* find smbios entry point structure */
> +    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> +        uint8_t sig[] = "_SM_";
> +        int i;
> +
> +        for (i = 0; i < sizeof sig - 1; ++i) {
> +            sig[i] = readb(off + i);
> +        }
> +
> +        if (!memcmp(sig, "_SM_", sizeof sig)) {
> +            /* signature match, but is this a valid entry point? */
> +            data->smbios_ep_addr = off;
> +            if (smbios_ep_table_ok(data)) {
> +                break;
> +            }
> +        }
> +    }
> +
> +    g_assert_cmphex(off, <, 0x100000);
>  }
>  
>  static inline bool smbios_single_instance(uint8_t type)
> @@ -767,8 +780,7 @@ static void test_acpi_one(const char *params, test_data 
> *data)
>          }
>      }
>  
> -    test_smbios_ep_address(data);
> -    test_smbios_ep_table(data);
> +    test_smbios_entry_point(data);
>      test_smbios_structs(data);
>  
>      qtest_quit(global_qtest);

I tried this out in my case which previously failed - worked great.

Thanks!

Bruce

Tested-by: Bruce Rogers <brogers@suse.com>
Gabriel L. Somlo April 28, 2015, 7:40 p.m. UTC | #2 
ping ?

On Tue, Mar 31, 2015 at 02:32:20PM -0400, Gabriel L. Somlo wrote:
> Rather than stopping at the first match for the SMBIOS signature
> ("_SM_") in the f-segment (0xF0000-0xFFFFF), continue scanning
> until either a valid entry point table is found, or the f-segment
> has been exhausted.
> 
> Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
> ---
>  tests/bios-tables-test.c | 76 ++++++++++++++++++++++++++++--------------------
>  1 file changed, 44 insertions(+), 32 deletions(-)
> 
> diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
> index 735ac61..f79d89a 100644
> --- a/tests/bios-tables-test.c
> +++ b/tests/bios-tables-test.c
> @@ -599,35 +599,15 @@ static void test_acpi_asl(test_data *data)
>      free_test_data(&exp_data);
>  }
>  
> -static void test_smbios_ep_address(test_data *data)
> -{
> -    uint32_t off;
> -
> -    /* find smbios entry point structure */
> -    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> -        uint8_t sig[] = "_SM_";
> -        int i;
> -
> -        for (i = 0; i < sizeof sig - 1; ++i) {
> -            sig[i] = readb(off + i);
> -        }
> -
> -        if (!memcmp(sig, "_SM_", sizeof sig)) {
> -            break;
> -        }
> -    }
> -
> -    g_assert_cmphex(off, <, 0x100000);
> -    data->smbios_ep_addr = off;
> -}
> -
> -static void test_smbios_ep_table(test_data *data)
> +static bool smbios_ep_table_ok(test_data *data)
>  {
>      struct smbios_entry_point *ep_table = &data->smbios_ep_table;
>      uint32_t addr = data->smbios_ep_addr;
>  
>      ACPI_READ_ARRAY(ep_table->anchor_string, addr);
> -    g_assert(!memcmp(ep_table->anchor_string, "_SM_", 4));
> +    if (memcmp(ep_table->anchor_string, "_SM_", 4)) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->checksum, addr);
>      ACPI_READ_FIELD(ep_table->length, addr);
>      ACPI_READ_FIELD(ep_table->smbios_major_version, addr);
> @@ -636,17 +616,50 @@ static void test_smbios_ep_table(test_data *data)
>      ACPI_READ_FIELD(ep_table->entry_point_revision, addr);
>      ACPI_READ_ARRAY(ep_table->formatted_area, addr);
>      ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr);
> -    g_assert(!memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5));
> +    if (memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->intermediate_checksum, addr);
>      ACPI_READ_FIELD(ep_table->structure_table_length, addr);
> -    g_assert_cmpuint(ep_table->structure_table_length, >, 0);
> +    if (ep_table->structure_table_length == 0) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->structure_table_address, addr);
>      ACPI_READ_FIELD(ep_table->number_of_structures, addr);
> -    g_assert_cmpuint(ep_table->number_of_structures, >, 0);
> +    if (ep_table->number_of_structures == 0) {
> +        return false;
> +    }
>      ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr);
> -    g_assert(!acpi_checksum((uint8_t *)ep_table, sizeof *ep_table));
> -    g_assert(!acpi_checksum((uint8_t *)ep_table + 0x10,
> -                            sizeof *ep_table - 0x10));
> +    if (acpi_checksum((uint8_t *)ep_table, sizeof *ep_table) ||
> +        acpi_checksum((uint8_t *)ep_table + 0x10, sizeof *ep_table - 0x10)) {
> +        return false;
> +    }
> +    return true;
> +}
> +
> +static void test_smbios_entry_point(test_data *data)
> +{
> +    uint32_t off;
> +
> +    /* find smbios entry point structure */
> +    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> +        uint8_t sig[] = "_SM_";
> +        int i;
> +
> +        for (i = 0; i < sizeof sig - 1; ++i) {
> +            sig[i] = readb(off + i);
> +        }
> +
> +        if (!memcmp(sig, "_SM_", sizeof sig)) {
> +            /* signature match, but is this a valid entry point? */
> +            data->smbios_ep_addr = off;
> +            if (smbios_ep_table_ok(data)) {
> +                break;
> +            }
> +        }
> +    }
> +
> +    g_assert_cmphex(off, <, 0x100000);
>  }
>  
>  static inline bool smbios_single_instance(uint8_t type)
> @@ -767,8 +780,7 @@ static void test_acpi_one(const char *params, test_data *data)
>          }
>      }
>  
> -    test_smbios_ep_address(data);
> -    test_smbios_ep_table(data);
> +    test_smbios_entry_point(data);
>      test_smbios_structs(data);
>  
>      qtest_quit(global_qtest);
> -- 
> 2.1.0
>
Michael S. Tsirkin April 28, 2015, 7:42 p.m. UTC | #3 
On Tue, Apr 28, 2015 at 03:40:37PM -0400, Gabriel L. Somlo wrote:
> ping ?
> 
> On Tue, Mar 31, 2015 at 02:32:20PM -0400, Gabriel L. Somlo wrote:
> > Rather than stopping at the first match for the SMBIOS signature
> > ("_SM_") in the f-segment (0xF0000-0xFFFFF), continue scanning
> > until either a valid entry point table is found, or the f-segment
> > has been exhausted.
> > 
> > Signed-off-by: Gabriel Somlo <somlo@cmu.edu>

I'm curious why do you want to do this.
Can you add this info in the commmit log?

> > ---
> >  tests/bios-tables-test.c | 76 ++++++++++++++++++++++++++++--------------------
> >  1 file changed, 44 insertions(+), 32 deletions(-)
> > 
> > diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
> > index 735ac61..f79d89a 100644
> > --- a/tests/bios-tables-test.c
> > +++ b/tests/bios-tables-test.c
> > @@ -599,35 +599,15 @@ static void test_acpi_asl(test_data *data)
> >      free_test_data(&exp_data);
> >  }
> >  
> > -static void test_smbios_ep_address(test_data *data)
> > -{
> > -    uint32_t off;
> > -
> > -    /* find smbios entry point structure */
> > -    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> > -        uint8_t sig[] = "_SM_";
> > -        int i;
> > -
> > -        for (i = 0; i < sizeof sig - 1; ++i) {
> > -            sig[i] = readb(off + i);
> > -        }
> > -
> > -        if (!memcmp(sig, "_SM_", sizeof sig)) {
> > -            break;
> > -        }
> > -    }
> > -
> > -    g_assert_cmphex(off, <, 0x100000);
> > -    data->smbios_ep_addr = off;
> > -}
> > -
> > -static void test_smbios_ep_table(test_data *data)
> > +static bool smbios_ep_table_ok(test_data *data)
> >  {
> >      struct smbios_entry_point *ep_table = &data->smbios_ep_table;
> >      uint32_t addr = data->smbios_ep_addr;
> >  
> >      ACPI_READ_ARRAY(ep_table->anchor_string, addr);
> > -    g_assert(!memcmp(ep_table->anchor_string, "_SM_", 4));
> > +    if (memcmp(ep_table->anchor_string, "_SM_", 4)) {
> > +        return false;
> > +    }
> >      ACPI_READ_FIELD(ep_table->checksum, addr);
> >      ACPI_READ_FIELD(ep_table->length, addr);
> >      ACPI_READ_FIELD(ep_table->smbios_major_version, addr);
> > @@ -636,17 +616,50 @@ static void test_smbios_ep_table(test_data *data)
> >      ACPI_READ_FIELD(ep_table->entry_point_revision, addr);
> >      ACPI_READ_ARRAY(ep_table->formatted_area, addr);
> >      ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr);
> > -    g_assert(!memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5));
> > +    if (memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)) {
> > +        return false;
> > +    }
> >      ACPI_READ_FIELD(ep_table->intermediate_checksum, addr);
> >      ACPI_READ_FIELD(ep_table->structure_table_length, addr);
> > -    g_assert_cmpuint(ep_table->structure_table_length, >, 0);
> > +    if (ep_table->structure_table_length == 0) {
> > +        return false;
> > +    }
> >      ACPI_READ_FIELD(ep_table->structure_table_address, addr);
> >      ACPI_READ_FIELD(ep_table->number_of_structures, addr);
> > -    g_assert_cmpuint(ep_table->number_of_structures, >, 0);
> > +    if (ep_table->number_of_structures == 0) {
> > +        return false;
> > +    }
> >      ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr);
> > -    g_assert(!acpi_checksum((uint8_t *)ep_table, sizeof *ep_table));
> > -    g_assert(!acpi_checksum((uint8_t *)ep_table + 0x10,
> > -                            sizeof *ep_table - 0x10));
> > +    if (acpi_checksum((uint8_t *)ep_table, sizeof *ep_table) ||
> > +        acpi_checksum((uint8_t *)ep_table + 0x10, sizeof *ep_table - 0x10)) {
> > +        return false;
> > +    }
> > +    return true;
> > +}
> > +
> > +static void test_smbios_entry_point(test_data *data)
> > +{
> > +    uint32_t off;
> > +
> > +    /* find smbios entry point structure */
> > +    for (off = 0xf0000; off < 0x100000; off += 0x10) {
> > +        uint8_t sig[] = "_SM_";
> > +        int i;
> > +
> > +        for (i = 0; i < sizeof sig - 1; ++i) {
> > +            sig[i] = readb(off + i);
> > +        }
> > +
> > +        if (!memcmp(sig, "_SM_", sizeof sig)) {
> > +            /* signature match, but is this a valid entry point? */
> > +            data->smbios_ep_addr = off;
> > +            if (smbios_ep_table_ok(data)) {
> > +                break;
> > +            }
> > +        }
> > +    }
> > +
> > +    g_assert_cmphex(off, <, 0x100000);
> >  }
> >  
> >  static inline bool smbios_single_instance(uint8_t type)
> > @@ -767,8 +780,7 @@ static void test_acpi_one(const char *params, test_data *data)
> >          }
> >      }
> >  
> > -    test_smbios_ep_address(data);
> > -    test_smbios_ep_table(data);
> > +    test_smbios_entry_point(data);
> >      test_smbios_structs(data);
> >  
> >      qtest_quit(global_qtest);
> > -- 
> > 2.1.0
> >
diff mbox

Patch

diff --git a/tests/bios-tables-test.c b/tests/bios-tables-test.c
index 735ac61..f79d89a 100644
--- a/tests/bios-tables-test.c
+++ b/tests/bios-tables-test.c
@@ -599,35 +599,15 @@  static void test_acpi_asl(test_data *data)
     free_test_data(&exp_data);
 }
 
-static void test_smbios_ep_address(test_data *data)
-{
-    uint32_t off;
-
-    /* find smbios entry point structure */
-    for (off = 0xf0000; off < 0x100000; off += 0x10) {
-        uint8_t sig[] = "_SM_";
-        int i;
-
-        for (i = 0; i < sizeof sig - 1; ++i) {
-            sig[i] = readb(off + i);
-        }
-
-        if (!memcmp(sig, "_SM_", sizeof sig)) {
-            break;
-        }
-    }
-
-    g_assert_cmphex(off, <, 0x100000);
-    data->smbios_ep_addr = off;
-}
-
-static void test_smbios_ep_table(test_data *data)
+static bool smbios_ep_table_ok(test_data *data)
 {
     struct smbios_entry_point *ep_table = &data->smbios_ep_table;
     uint32_t addr = data->smbios_ep_addr;
 
     ACPI_READ_ARRAY(ep_table->anchor_string, addr);
-    g_assert(!memcmp(ep_table->anchor_string, "_SM_", 4));
+    if (memcmp(ep_table->anchor_string, "_SM_", 4)) {
+        return false;
+    }
     ACPI_READ_FIELD(ep_table->checksum, addr);
     ACPI_READ_FIELD(ep_table->length, addr);
     ACPI_READ_FIELD(ep_table->smbios_major_version, addr);
@@ -636,17 +616,50 @@  static void test_smbios_ep_table(test_data *data)
     ACPI_READ_FIELD(ep_table->entry_point_revision, addr);
     ACPI_READ_ARRAY(ep_table->formatted_area, addr);
     ACPI_READ_ARRAY(ep_table->intermediate_anchor_string, addr);
-    g_assert(!memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5));
+    if (memcmp(ep_table->intermediate_anchor_string, "_DMI_", 5)) {
+        return false;
+    }
     ACPI_READ_FIELD(ep_table->intermediate_checksum, addr);
     ACPI_READ_FIELD(ep_table->structure_table_length, addr);
-    g_assert_cmpuint(ep_table->structure_table_length, >, 0);
+    if (ep_table->structure_table_length == 0) {
+        return false;
+    }
     ACPI_READ_FIELD(ep_table->structure_table_address, addr);
     ACPI_READ_FIELD(ep_table->number_of_structures, addr);
-    g_assert_cmpuint(ep_table->number_of_structures, >, 0);
+    if (ep_table->number_of_structures == 0) {
+        return false;
+    }
     ACPI_READ_FIELD(ep_table->smbios_bcd_revision, addr);
-    g_assert(!acpi_checksum((uint8_t *)ep_table, sizeof *ep_table));
-    g_assert(!acpi_checksum((uint8_t *)ep_table + 0x10,
-                            sizeof *ep_table - 0x10));
+    if (acpi_checksum((uint8_t *)ep_table, sizeof *ep_table) ||
+        acpi_checksum((uint8_t *)ep_table + 0x10, sizeof *ep_table - 0x10)) {
+        return false;
+    }
+    return true;
+}
+
+static void test_smbios_entry_point(test_data *data)
+{
+    uint32_t off;
+
+    /* find smbios entry point structure */
+    for (off = 0xf0000; off < 0x100000; off += 0x10) {
+        uint8_t sig[] = "_SM_";
+        int i;
+
+        for (i = 0; i < sizeof sig - 1; ++i) {
+            sig[i] = readb(off + i);
+        }
+
+        if (!memcmp(sig, "_SM_", sizeof sig)) {
+            /* signature match, but is this a valid entry point? */
+            data->smbios_ep_addr = off;
+            if (smbios_ep_table_ok(data)) {
+                break;
+            }
+        }
+    }
+
+    g_assert_cmphex(off, <, 0x100000);
 }
 
 static inline bool smbios_single_instance(uint8_t type)
@@ -767,8 +780,7 @@  static void test_acpi_one(const char *params, test_data *data)
         }
     }
 
-    test_smbios_ep_address(data);
-    test_smbios_ep_table(data);
+    test_smbios_entry_point(data);
     test_smbios_structs(data);
 
     qtest_quit(global_qtest);