diff options
| author | J. Bruce Fields <bfields@redhat.com> | 2017-04-21 21:26:30 +0200 |
|---|---|---|
| committer | J. Bruce Fields <bfields@redhat.com> | 2017-04-25 22:36:23 +0200 |
| commit | 13bf9fbff0e5e099e2b6f003a0ab8ae145436309 (patch) | |
| tree | 950c4317be5f1138b1659aaa535de228ea51c36c | |
| parent | nfsd4: minor NFSv2/v3 write decoding cleanup (diff) | |
| download | linux-13bf9fbff0e5e099e2b6f003a0ab8ae145436309.tar.xz linux-13bf9fbff0e5e099e2b6f003a0ab8ae145436309.zip | |
nfsd: stricter decoding of write-like NFSv2/v3 ops
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>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
| -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 d18cfddbe115..452334694a5d 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -369,6 +369,8 @@ 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. */ @@ -472,6 +474,8 @@ 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 59bd88a23a3d..de07ff625777 100644 --- a/fs/nfsd/nfsxdr.c +++ b/fs/nfsd/nfsxdr.c @@ -302,6 +302,8 @@ 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; /* |