Hi,

I can't find anything guaranteeing that 'ubi_num' cannot be <0 in 
drivers/mtd/ubi/kapi.c::ubi_open_volume(), and in fact the code 
even tests for that and errors out if so. Unfortunately the test 
for "ubi_num < 0" happens after we've already used 'ubi_num' as 
an array index - bad thing to do if it is negative.
This patch moves the test earlier in the function and then moves 
the indexing using that variable after the check. A bit safer :-) 


Signed-off-by: Jesper Juhl <[EMAIL PROTECTED]>
---

 drivers/mtd/ubi/kapi.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
index 4a458e8..5130e54 100644
--- a/drivers/mtd/ubi/kapi.c
+++ b/drivers/mtd/ubi/kapi.c
@@ -99,16 +99,21 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int 
vol_id, int mode)
 {
        int err;
        struct ubi_volume_desc *desc;
-       struct ubi_device *ubi = ubi_devices[ubi_num];
+       struct ubi_device *ubi;
        struct ubi_volume *vol;
 
        dbg_msg("open device %d volume %d, mode %d", ubi_num, vol_id, mode);
 
        err = -ENODEV;
+       if (ubi_num < 0)
+               return ERR_PTR(err);
+
+       ubi = ubi_devices[ubi_num];
+       
        if (!try_module_get(THIS_MODULE))
                return ERR_PTR(err);
 
-       if (ubi_num < 0 || ubi_num >= UBI_MAX_DEVICES || !ubi)
+       if (ubi_num >= UBI_MAX_DEVICES || !ubi)
                goto out_put;
 
        err = -EINVAL;


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