[PATCH 08/10] staging/lustre/llite: Fix integer overflow in ll_fid2path

[Oleg Drokin]

Reported by Dan Carpenter <dan.carpenter@xxxxxxxxxx>

outsize = sizeof(*gfout) + gfin->gf_pathlen;

Where outsize is int and gf_pathlen is u32 from userspace
can lead to integer overflowwhere outsize is some small number
less than sizeof(*gfout)

Add a check for pathlen to be of sensical size.

Signed-off-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
Reviewed-on: http://review.whamcloud.com/11412
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-5476
Reviewed-by: Dmitry Eremin <dmitry.eremin@xxxxxxxxx>
Reviewed-by: John L. Hammond <john.hammond@xxxxxxxxx>
---
 drivers/staging/lustre/lustre/llite/file.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/lustre/lustre/llite/file.c b/drivers/staging/lustre/lustre/llite/file.c
index d3874e1..4a33638 100644
--- a/drivers/staging/lustre/lustre/llite/file.c
+++ b/drivers/staging/lustre/lustre/llite/file.c
@@ -1719,6 +1719,9 @@ int ll_fid2path(struct inode *inode, void __user *arg)
 	if (get_user(pathlen, &gfin->gf_pathlen))
 		return -EFAULT;
 
+	if (pathlen > PATH_MAX)
+		return -EINVAL;
+
 	outsize = sizeof(*gfout) + pathlen;
 
 	OBD_ALLOC(gfout, outsize);
-- 
1.9.3

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