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| author | Miklos Szeredi <mszeredi@redhat.com> | 2016-10-01 08:32:32 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-02-23 06:54:07 +0300 |
| commit | cbe308a4471f9dc65d1059bd2f9e242ddcf4b548 (patch) | |
| tree | abac907c7c1303c33532b07d470c7b33dbcfcd79 | |
| parent | 2787db9e6b9600dab0e0aae39d197a3d21c890b5 (diff) | |
| download | linux-cbe308a4471f9dc65d1059bd2f9e242ddcf4b548.tar.xz | |
fuse: listxattr: verify xattr list
commit cb3ae6d25a5471be62bfe6ac1fccc0e91edeaba0 upstream.
Make sure userspace filesystem is returning a well formed list of xattr
names (zero or more nonzero length, null terminated strings).
[Michael Theall: only verify in the nonzero size case]
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
[bwh: Backported to 3.16: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | fs/fuse/dir.c | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/fs/fuse/dir.c b/fs/fuse/dir.c index d4ba4e1a7fb9..2ef8defac554 100644 --- a/fs/fuse/dir.c +++ b/fs/fuse/dir.c @@ -1968,6 +1968,23 @@ static ssize_t fuse_getxattr(struct dentry *entry, const char *name, return ret; } +static int fuse_verify_xattr_list(char *list, size_t size) +{ + size_t origsize = size; + + while (size) { + size_t thislen = strnlen(list, size); + + if (!thislen || thislen == size) + return -EIO; + + size -= thislen + 1; + list += thislen + 1; + } + + return origsize; +} + static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size) { struct inode *inode = entry->d_inode; @@ -2006,9 +2023,11 @@ static ssize_t fuse_listxattr(struct dentry *entry, char *list, size_t size) } fuse_request_send(fc, req); ret = req->out.h.error; - if (!ret) + if (!ret) { ret = size ? req->out.args[0].size : outarg.size; - else { + if (ret > 0 && size) + ret = fuse_verify_xattr_list(list, ret); + } else { if (ret == -ENOSYS) { fc->no_listxattr = 1; ret = -EOPNOTSUPP; |