* [PATCH kvm-unit-tests] fw_cfg: avoid index out of bounds
@ 2020-07-30 21:58 Paolo Bonzini
2020-07-31 16:00 ` Nadav Amit
0 siblings, 1 reply; 3+ messages in thread
From: Paolo Bonzini @ 2020-07-30 21:58 UTC (permalink / raw)
To: kvm
clang compilation fails with
lib/x86/fwcfg.c:32:3: error: array index 17 is past the end of the array (which contains 16 elements) [-Werror,-Warray-bounds]
fw_override[FW_CFG_MAX_RAM] = atol(str) * 1024 * 1024;
The reason is that FW_CFG_MAX_RAM does not exist in the fw-cfg spec and was
added for bare metal support. Fix the size of the array and rename FW_CFG_MAX_ENTRY
to FW_CFG_NUM_ENTRIES, so that it is clear that it must be one plus the
highest valid entry.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
lib/x86/fwcfg.c | 6 +++---
lib/x86/fwcfg.h | 5 ++++-
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
index c2aaf5a..1734afb 100644
--- a/lib/x86/fwcfg.c
+++ b/lib/x86/fwcfg.c
@@ -4,7 +4,7 @@
static struct spinlock lock;
-static long fw_override[FW_CFG_MAX_ENTRY];
+static long fw_override[FW_CFG_NUM_ENTRIES];
static bool fw_override_done;
bool no_test_device;
@@ -15,7 +15,7 @@ static void read_cfg_override(void)
int i;
/* Initialize to negative value that would be considered as invalid */
- for (i = 0; i < FW_CFG_MAX_ENTRY; i++)
+ for (i = 0; i < FW_CFG_NUM_ENTRIES; i++)
fw_override[i] = -1;
if ((str = getenv("NR_CPUS")))
@@ -44,7 +44,7 @@ static uint64_t fwcfg_get_u(uint16_t index, int bytes)
if (!fw_override_done)
read_cfg_override();
- if (index < FW_CFG_MAX_ENTRY && fw_override[index] >= 0)
+ if (index < FW_CFG_NUM_ENTRIES && fw_override[index] >= 0)
return fw_override[index];
spin_lock(&lock);
diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
index 64d4c6e..ac4257e 100644
--- a/lib/x86/fwcfg.h
+++ b/lib/x86/fwcfg.h
@@ -20,9 +20,12 @@
#define FW_CFG_NUMA 0x0d
#define FW_CFG_BOOT_MENU 0x0e
#define FW_CFG_MAX_CPUS 0x0f
-#define FW_CFG_MAX_ENTRY 0x10
+
+/* Dummy entries used when running on bare metal */
#define FW_CFG_MAX_RAM 0x11
+#define FW_CFG_NUM_ENTRIES (FW_CFG_MAX_RAM + 1)
+
#define FW_CFG_WRITE_CHANNEL 0x4000
#define FW_CFG_ARCH_LOCAL 0x8000
#define FW_CFG_ENTRY_MASK ~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL)
--
2.26.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH kvm-unit-tests] fw_cfg: avoid index out of bounds
2020-07-30 21:58 [PATCH kvm-unit-tests] fw_cfg: avoid index out of bounds Paolo Bonzini
@ 2020-07-31 16:00 ` Nadav Amit
2020-07-31 16:05 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Nadav Amit @ 2020-07-31 16:00 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm
>
> On Jul 30, 2020, at 2:58 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> clang compilation fails with
>
> lib/x86/fwcfg.c:32:3: error: array index 17 is past the end of the array (which contains 16 elements) [-Werror,-Warray-bounds]
> fw_override[FW_CFG_MAX_RAM] = atol(str) * 1024 * 1024;
>
> The reason is that FW_CFG_MAX_RAM does not exist in the fw-cfg spec and was
> added for bare metal support. Fix the size of the array and rename FW_CFG_MAX_ENTRY
> to FW_CFG_NUM_ENTRIES, so that it is clear that it must be one plus the
> highest valid entry.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> lib/x86/fwcfg.c | 6 +++---
> lib/x86/fwcfg.h | 5 ++++-
> 2 files changed, 7 insertions(+), 4 deletions(-)
>
> diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
> index c2aaf5a..1734afb 100644
> --- a/lib/x86/fwcfg.c
> +++ b/lib/x86/fwcfg.c
> @@ -4,7 +4,7 @@
>
> static struct spinlock lock;
>
> -static long fw_override[FW_CFG_MAX_ENTRY];
> +static long fw_override[FW_CFG_NUM_ENTRIES];
> static bool fw_override_done;
>
> bool no_test_device;
> @@ -15,7 +15,7 @@ static void read_cfg_override(void)
> int i;
>
> /* Initialize to negative value that would be considered as invalid */
> - for (i = 0; i < FW_CFG_MAX_ENTRY; i++)
> + for (i = 0; i < FW_CFG_NUM_ENTRIES; i++)
> fw_override[i] = -1;
>
> if ((str = getenv("NR_CPUS")))
> @@ -44,7 +44,7 @@ static uint64_t fwcfg_get_u(uint16_t index, int bytes)
> if (!fw_override_done)
> read_cfg_override();
>
> - if (index < FW_CFG_MAX_ENTRY && fw_override[index] >= 0)
> + if (index < FW_CFG_NUM_ENTRIES && fw_override[index] >= 0)
> return fw_override[index];
>
> spin_lock(&lock);
> diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
> index 64d4c6e..ac4257e 100644
> --- a/lib/x86/fwcfg.h
> +++ b/lib/x86/fwcfg.h
> @@ -20,9 +20,12 @@
> #define FW_CFG_NUMA 0x0d
> #define FW_CFG_BOOT_MENU 0x0e
> #define FW_CFG_MAX_CPUS 0x0f
> -#define FW_CFG_MAX_ENTRY 0x10
> +
> +/* Dummy entries used when running on bare metal */
> #define FW_CFG_MAX_RAM 0x11
>
> +#define FW_CFG_NUM_ENTRIES (FW_CFG_MAX_RAM + 1)
> +
> #define FW_CFG_WRITE_CHANNEL 0x4000
> #define FW_CFG_ARCH_LOCAL 0x8000
> #define FW_CFG_ENTRY_MASK ~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL)
> —
> 2.26.2
For the record: I did send a patch more than two weeks ago to fix this
problem (that I created).
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH kvm-unit-tests] fw_cfg: avoid index out of bounds
2020-07-31 16:00 ` Nadav Amit
@ 2020-07-31 16:05 ` Paolo Bonzini
0 siblings, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2020-07-31 16:05 UTC (permalink / raw)
To: Nadav Amit; +Cc: kvm
On 31/07/20 18:00, Nadav Amit wrote:
>>
>> On Jul 30, 2020, at 2:58 PM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>> clang compilation fails with
>>
>> lib/x86/fwcfg.c:32:3: error: array index 17 is past the end of the array (which contains 16 elements) [-Werror,-Warray-bounds]
>> fw_override[FW_CFG_MAX_RAM] = atol(str) * 1024 * 1024;
>>
>> The reason is that FW_CFG_MAX_RAM does not exist in the fw-cfg spec and was
>> added for bare metal support. Fix the size of the array and rename FW_CFG_MAX_ENTRY
>> to FW_CFG_NUM_ENTRIES, so that it is clear that it must be one plus the
>> highest valid entry.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
>> ---
>> lib/x86/fwcfg.c | 6 +++---
>> lib/x86/fwcfg.h | 5 ++++-
>> 2 files changed, 7 insertions(+), 4 deletions(-)
>>
>> diff --git a/lib/x86/fwcfg.c b/lib/x86/fwcfg.c
>> index c2aaf5a..1734afb 100644
>> --- a/lib/x86/fwcfg.c
>> +++ b/lib/x86/fwcfg.c
>> @@ -4,7 +4,7 @@
>>
>> static struct spinlock lock;
>>
>> -static long fw_override[FW_CFG_MAX_ENTRY];
>> +static long fw_override[FW_CFG_NUM_ENTRIES];
>> static bool fw_override_done;
>>
>> bool no_test_device;
>> @@ -15,7 +15,7 @@ static void read_cfg_override(void)
>> int i;
>>
>> /* Initialize to negative value that would be considered as invalid */
>> - for (i = 0; i < FW_CFG_MAX_ENTRY; i++)
>> + for (i = 0; i < FW_CFG_NUM_ENTRIES; i++)
>> fw_override[i] = -1;
>>
>> if ((str = getenv("NR_CPUS")))
>> @@ -44,7 +44,7 @@ static uint64_t fwcfg_get_u(uint16_t index, int bytes)
>> if (!fw_override_done)
>> read_cfg_override();
>>
>> - if (index < FW_CFG_MAX_ENTRY && fw_override[index] >= 0)
>> + if (index < FW_CFG_NUM_ENTRIES && fw_override[index] >= 0)
>> return fw_override[index];
>>
>> spin_lock(&lock);
>> diff --git a/lib/x86/fwcfg.h b/lib/x86/fwcfg.h
>> index 64d4c6e..ac4257e 100644
>> --- a/lib/x86/fwcfg.h
>> +++ b/lib/x86/fwcfg.h
>> @@ -20,9 +20,12 @@
>> #define FW_CFG_NUMA 0x0d
>> #define FW_CFG_BOOT_MENU 0x0e
>> #define FW_CFG_MAX_CPUS 0x0f
>> -#define FW_CFG_MAX_ENTRY 0x10
>> +
>> +/* Dummy entries used when running on bare metal */
>> #define FW_CFG_MAX_RAM 0x11
>>
>> +#define FW_CFG_NUM_ENTRIES (FW_CFG_MAX_RAM + 1)
>> +
>> #define FW_CFG_WRITE_CHANNEL 0x4000
>> #define FW_CFG_ARCH_LOCAL 0x8000
>> #define FW_CFG_ENTRY_MASK ~(FW_CFG_WRITE_CHANNEL | FW_CFG_ARCH_LOCAL)
>> —
>> 2.26.2
>
> For the record: I did send a patch more than two weeks ago to fix this
> problem (that I created).
Oops, sorry. I just saw it on the gitlab CI, I must have missed your patch.
Paolo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2020-07-30 21:58 [PATCH kvm-unit-tests] fw_cfg: avoid index out of bounds Paolo Bonzini
2020-07-31 16:00 ` Nadav Amit
2020-07-31 16:05 ` Paolo Bonzini
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