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authorJia-Ju Bai <baijiaju1990@gmail.com>2019-07-24 10:22:42 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-25 15:32:51 +0200
commitbbe70e4e421116db0af3acf84cbce3c3f6cac53e (patch)
tree189d5d1d40f6f7584304ca23f3f047fbb233e1a0 /fs/kernfs
parent2fd60da46da76948b8cc561ae8cc902209686253 (diff)
downloadlinux-bbe70e4e421116db0af3acf84cbce3c3f6cac53e.tar.bz2
fs: kernfs: Fix possible null-pointer dereferences in kernfs_path_from_node_locked()
In kernfs_path_from_node_locked(), there is an if statement on line 147 to check whether buf is NULL: if (buf) When buf is NULL, it is used on line 151: len += strlcpy(buf + len, parent_str, ...) and line 158: len += strlcpy(buf + len, "/", ...) and line 160: len += strlcpy(buf + len, kn->name, ...) Thus, possible null-pointer dereferences may occur. To fix these possible bugs, buf is checked before being used. If it is NULL, -EINVAL is returned. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com> Link: https://lore.kernel.org/r/20190724022242.27505-1-baijiaju1990@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index ddf537923a0a..6ebae6bbe6a5 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -137,6 +137,9 @@ 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;
@@ -144,8 +147,7 @@ static int kernfs_path_from_node_locked(struct kernfs_node *kn_to,
depth_to = kernfs_depth(common, kn_to);
depth_from = kernfs_depth(common, kn_from);
- if (buf)
- buf[0] = '\0';
+ buf[0] = '\0';
for (i = 0; i < depth_from; i++)
len += strlcpy(buf + len, parent_str,