[Qemu-devel] [PATCH] spapr_nvram: Check return value from blk_getlength()

[Qemu-devel] [PATCH] spapr_nvram: Check return value from blk_getlength()

[Peter Maydell]

The blk_getlength() function can return an error value if the
image size cannot be determined. Check for this rather than
ploughing on and trying to g_malloc0() a negative number.
(Spotted by Coverity, CID 1288484.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/nvram/spapr_nvram.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/hw/nvram/spapr_nvram.c b/hw/nvram/spapr_nvram.c
index aa5d2c1..bc355a4 100644
--- a/hw/nvram/spapr_nvram.c
+++ b/hw/nvram/spapr_nvram.c
@@ -144,7 +144,15 @@ static void spapr_nvram_realize(VIOsPAPRDevice *dev, Error **errp)
     int ret;
 
     if (nvram->blk) {
-        nvram->size = blk_getlength(nvram->blk);
+        int64_t len = blk_getlength(nvram->blk);
+
+        if (len < 0) {
+            error_setg_errno(errp, -len,
+                             "could not get length of backing image");
+            return;
+        }
+
+        nvram->size = len;
 
         ret = blk_set_perm(nvram->blk,
                            BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
-- 
2.7.4

Re: [Qemu-devel] [PATCH] spapr_nvram: Check return value from blk_getlength()

[David Gibson]

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On Mon, Jun 05, 2017 at 04:14:17PM +0100, Peter Maydell wrote:
> The blk_getlength() function can return an error value if the
> image size cannot be determined. Check for this rather than
> ploughing on and trying to g_malloc0() a negative number.
> (Spotted by Coverity, CID 1288484.)
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Applied to ppc-for-2.10, thanks.

> ---
>  hw/nvram/spapr_nvram.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/nvram/spapr_nvram.c b/hw/nvram/spapr_nvram.c
> index aa5d2c1..bc355a4 100644
> --- a/hw/nvram/spapr_nvram.c
> +++ b/hw/nvram/spapr_nvram.c
> @@ -144,7 +144,15 @@ static void spapr_nvram_realize(VIOsPAPRDevice *dev, Error **errp)
>      int ret;
>  
>      if (nvram->blk) {
> -        nvram->size = blk_getlength(nvram->blk);
> +        int64_t len = blk_getlength(nvram->blk);
> +
> +        if (len < 0) {
> +            error_setg_errno(errp, -len,
> +                             "could not get length of backing image");
> +            return;
> +        }
> +
> +        nvram->size = len;
>  
>          ret = blk_set_perm(nvram->blk,
>                             BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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