5.4-stable review patch. If anyone has any objections, please let me know.
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From: Chuck Lever chuck.lever@oracle.com
[ Upstream commit e6faac3f58c7c4176b66f63def17a34232a17b0e ]
iattr::ia_size is a loff_t, which is a signed 64-bit type. NFSv3 and NFSv4 both define file size as an unsigned 64-bit type. Thus there is a range of valid file size values an NFS client can send that is already larger than Linux can handle.
Currently decode_fattr4() dumps a full u64 value into ia_size. If that value happens to be larger than S64_MAX, then ia_size underflows. I'm about to fix up the NFSv3 behavior as well, so let's catch the underflow in the common code path: nfsd_setattr().
Cc: stable@vger.kernel.org Signed-off-by: Chuck Lever chuck.lever@oracle.com (cherry picked from commit e6faac3f58c7c4176b66f63def17a34232a17b0e) [Larry: backport to 5.4.y. Minor conflict resolved due to missing commit 2f221d6f7b88 attr: handle idmapped mounts] Signed-off-by: Larry Bassel larry.bassel@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfsd/vfs.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6aa968bee0ce1..bee4fdf6e239a 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -448,6 +448,10 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, .ia_size = iap->ia_size, };
+ host_err = -EFBIG; + if (iap->ia_size < 0) + goto out_unlock; + host_err = notify_change(dentry, &size_attr, NULL); if (host_err) goto out_unlock;