Messages in this thread Patch in this message | | | From | Zhen Lei <> | Subject | [PATCH] kernfs: fix potential null-ptr-deref in kernfs_path_from_node_locked() | Date | Wed, 23 Nov 2022 10:04:19 +0800 |
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Ensure that the 'buf' is not empty before strlcpy() uses it.
Commit bbe70e4e4211 ("fs: kernfs: Fix possible null-pointer dereferences in kernfs_path_from_node_locked()") first noticed this, but it didn't fix it completely.
Fixes: 9f6df573a404 ("kernfs: Add API to generate relative kernfs path") Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com> --- fs/kernfs/dir.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index f33b3baad07cb36..b2422265c86edf2 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -140,6 +140,9 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, size_t depth_from, depth_to, len = 0; int i, j; + if (!buf) + return -EINVAL; + if (!kn_to) return strlcpy(buf, "(null)", buflen); @@ -149,9 +152,6 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to, if (kn_from == kn_to) return strlcpy(buf, "/", buflen); - if (!buf) - return -EINVAL; - common = kernfs_common_ancestor(kn_from, kn_to); if (WARN_ON(!common)) return -EINVAL; -- 2.25.1
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