diff options
| author | J. Bruce Fields <bfields@redhat.com> | 2017-04-21 22:26:30 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-06-05 23:13:56 +0300 |
| commit | 6b9ba0c00cb068a50a409bbdc7cfbe473f1c01a3 (patch) | |
| tree | f0689d0249c6d5fb642b706731d2578e7e4d5919 /fs | |
| parent | 4625f286522abbb36c49a17cdb9c0bc008fd3ce2 (diff) | |
| download | linux-6b9ba0c00cb068a50a409bbdc7cfbe473f1c01a3.tar.xz | |
nfsd: stricter decoding of write-like NFSv2/v3 ops
commit 13bf9fbff0e5e099e2b6f003a0ab8ae145436309 upstream.
The NFSv2/v3 code does not systematically check whether we decode past
the end of the buffer. This generally appears to be harmless, but there
are a few places where we do arithmetic on the pointers involved and
don't account for the possibility that a length could be negative. Add
checks to catch these.
Reported-by: Tuomas Haanpää <thaan@synopsys.com>
Reported-by: Ari Kauppi <ari@synopsys.com>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/nfsd/nfs3xdr.c | 4 | ||||
| -rw-r--r-- | fs/nfsd/nfsxdr.c | 2 |
2 files changed, 6 insertions, 0 deletions
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index f7be3843cd39..7b382f82d946 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -363,6 +363,8 @@ nfs3svc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p, args->count = ntohl(*p++); args->stable = ntohl(*p++); len = args->len = ntohl(*p++); + if ((void *)p > head->iov_base + head->iov_len) + return 0; /* * The count must equal the amount of data passed. */ @@ -467,6 +469,8 @@ nfs3svc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p, /* first copy and check from the first page */ old = (char*)p; vec = &rqstp->rq_arg.head[0]; + if ((void *)old > vec->iov_base + vec->iov_len) + return 0; avail = vec->iov_len - (old - (char*)vec->iov_base); while (len && avail && *old) { *new++ = *old++; diff --git a/fs/nfsd/nfsxdr.c b/fs/nfsd/nfsxdr.c index 5ca15616211d..830f29b2ebc2 100644 --- a/fs/nfsd/nfsxdr.c +++ b/fs/nfsd/nfsxdr.c @@ -298,6 +298,8 @@ nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p, * bytes. */ hdr = (void*)p - head->iov_base; + if (hdr > head->iov_len) + return 0; dlen = head->iov_len + rqstp->rq_arg.page_len - hdr; /* |