From 0169b49d52400a6035cd0f2ccd08bcba061a1a9b Mon Sep 17 00:00:00 2001 From: Jesper Juhl Date: Sat, 4 Aug 2007 01:25:26 +0200 Subject: [PATCH] UBI: don't use array index before testing if it is negative 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 Signed-off-by: Artem Bityutskiy --- drivers/mtd/ubi/kapi.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c index 4a458e83e4e9..03c774f41549 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; -- 2.20.1