Re: [Qemu-devel] [PATCH 2/3] hw/9pfs/virtio-9p-local.c: use snprintf() instead of sprintf()

[Chen Gang <gang.chen.5i5j@gmail.com>]

On 03/03/2014 04:34 PM, Markus Armbruster wrote:
> Chen Gang <gang.chen.5i5j@gmail.com> writes:
> 
>> 'ctx->fs_root' + 'path'/'fullname.data' may be larger than PATH_MAX, so
>> need use snprintf() instead of sprintf() just like another area have done in 9pfs.
>>
>> Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
>> ---
>>  hw/9pfs/virtio-9p-local.c | 7 ++++---
>>  1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/hw/9pfs/virtio-9p-local.c b/hw/9pfs/virtio-9p-local.c
>> index 77a04cd..61be75a 100644
>> --- a/hw/9pfs/virtio-9p-local.c
>> +++ b/hw/9pfs/virtio-9p-local.c
>> @@ -898,7 +898,8 @@ static int local_remove(FsContext *ctx, const char *path)
>>           * directory
>>           */
>>          if (S_ISDIR(stbuf.st_mode)) {
>> -            sprintf(buffer, "%s/%s/%s", ctx->fs_root, path, VIRTFS_META_DIR);
>> +            snprintf(buffer, ARRAY_SIZE(buffer), "%s/%s/%s",
>> +                     ctx->fs_root, path, VIRTFS_META_DIR);
>>              err = remove(buffer);
>>              if (err < 0 && errno != ENOENT) {
>>                  /*
>> @@ -1033,8 +1034,8 @@ static int local_unlinkat(FsContext *ctx, V9fsPath *dir,
>>               * If directory remove .virtfs_metadata contained in the
>>               * directory
>>               */
>> -            sprintf(buffer, "%s/%s/%s", ctx->fs_root,
>> -                    fullname.data, VIRTFS_META_DIR);
>> +            snprintf(buffer, ARRAY_SIZE(buffer), "%s/%s/%s", ctx->fs_root,
>> +                     fullname.data, VIRTFS_META_DIR);
>>              ret = remove(buffer);
>>              if (ret < 0 && errno != ENOENT) {
>>                  /*
> 
> Turns a buffer overrun bug into a truncation bug.  The next commit fixes
> truncation bugs including this one.  Would be nice to spell this out in
> the commit message.  Perhaps Aneesh can do it on commit.
> 

Please help doing it on commit.

Thanks.
-- 
Chen Gang

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