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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2018-07-07 17:52:47 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-16 22:38:57 +0200 |
| commit | a75e78f21f9ad4b810868c89dbbabcc3931591ca (patch) | |
| tree | 5f2d9f66299b62c9fea792a499a152f205ff26a3 | |
| parent | bdae566d5d9733b6e32b378668b84eadf28a94d4 (diff) | |
| download | linux-a75e78f21f9ad4b810868c89dbbabcc3931591ca.tar.bz2 | |
kernfs: Fix range checks in kernfs_get_target_path
The terminating NUL byte is only there because the buffer is
allocated with kzalloc(PAGE_SIZE, GFP_KERNEL), but since the
range-check is off-by-one, and PAGE_SIZE==PATH_MAX, the
returned string may not be zero-terminated if it is exactly
PATH_MAX characters long. Furthermore also the initial loop
may theoretically exceed PATH_MAX and cause a fault.
Signed-off-by: Bernd Edlinger <bernd.edlinger@hotmail.de>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/kernfs/symlink.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c index 305b220af45d..162f43b80c84 100644 --- a/fs/kernfs/symlink.c +++ b/fs/kernfs/symlink.c @@ -72,6 +72,9 @@ static int kernfs_get_target_path(struct kernfs_node *parent, if (base == kn) break; + if ((s - path) + 3 >= PATH_MAX) + return -ENAMETOOLONG; + strcpy(s, "../"); s += 3; base = base->parent; @@ -88,7 +91,7 @@ static int kernfs_get_target_path(struct kernfs_node *parent, if (len < 2) return -EINVAL; len--; - if ((s - path) + len > PATH_MAX) + if ((s - path) + len >= PATH_MAX) return -ENAMETOOLONG; /* reverse fillup of target string from target to base */ |