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NFSv4: Fix Oopses in the fs_locations code

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If the server sends us a pathname with more components than the client
limit of NFS4_PATHNAME_MAXCOMPONENTS, more server entries than the client
limit of NFS4_FS_LOCATION_MAXSERVERS, or sends a total number of
fs_locations entries than the client limit of NFS4_FS_LOCATIONS_MAXENTRIES
then we will currently Oops because the limit checks are done _after_ we've
decoded the data into the arrays.

Reported-by: fanchaoting<fanchaoting@cn.fujitsu.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Trond Myklebust 2013-03-27 11:54:45 -04:00
parent 91876b13b8
commit 809b426c7f
1 changed files with 20 additions and 23 deletions
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43
fs/nfs/nfs4xdr.c
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@ -3496,8 +3496,11 @@ static int decode_pathname(struct xdr_stream *xdr, struct nfs4_pathname *path)
if (n == 0)
goto root_path;
dprintk("pathname4: ");
path->ncomponents = 0;
while (path->ncomponents < n) {
if (n > NFS4_PATHNAME_MAXCOMPONENTS) {
dprintk("cannot parse %d components in path\n", n);
goto out_eio;
}
for (path->ncomponents = 0; path->ncomponents < n; path->ncomponents++) {
struct nfs4_string *component = &path->components[path->ncomponents];
status = decode_opaque_inline(xdr, &component->len, &component->data);
if (unlikely(status != 0))
@ -3506,12 +3509,6 @@ static int decode_pathname(struct xdr_stream *xdr, struct nfs4_pathname *path)
pr_cont("%s%.*s ",
(path->ncomponents != n ? "/ " : ""),
component->len, component->data);
if (path->ncomponents < NFS4_PATHNAME_MAXCOMPONENTS)
path->ncomponents++;
else {
dprintk("cannot parse %d components in path\n", n);
goto out_eio;
}
}
out:
return status;
@ -3556,27 +3553,23 @@ static int decode_attr_fs_locations(struct xdr_stream *xdr, uint32_t *bitmap, st
n = be32_to_cpup(p);
if (n <= 0)
goto out_eio;
res->nlocations = 0;
while (res->nlocations < n) {
for (res->nlocations = 0; res->nlocations < n; res->nlocations++) {
u32 m;
struct nfs4_fs_location *loc = &res->locations[res->nlocations];
struct nfs4_fs_location *loc;
if (res->nlocations == NFS4_FS_LOCATIONS_MAXENTRIES)
break;
loc = &res->locations[res->nlocations];
p = xdr_inline_decode(xdr, 4);
if (unlikely(!p))
goto out_overflow;
m = be32_to_cpup(p);
loc->nservers = 0;
dprintk("%s: servers:\n", __func__);
while (loc->nservers < m) {
struct nfs4_string *server = &loc->servers[loc->nservers];
status = decode_opaque_inline(xdr, &server->len, &server->data);
if (unlikely(status != 0))
goto out_eio;
dprintk("%s ", server->data);
if (loc->nservers < NFS4_FS_LOCATION_MAXSERVERS)
loc->nservers++;
else {
for (loc->nservers = 0; loc->nservers < m; loc->nservers++) {
struct nfs4_string *server;
if (loc->nservers == NFS4_FS_LOCATION_MAXSERVERS) {
unsigned int i;
dprintk("%s: using first %u of %u servers "
"returned for location %u\n",
@ -3590,13 +3583,17 @@ static int decode_attr_fs_locations(struct xdr_stream *xdr, uint32_t *bitmap, st
if (unlikely(status != 0))
goto out_eio;
}
break;
}
server = &loc->servers[loc->nservers];
status = decode_opaque_inline(xdr, &server->len, &server->data);
if (unlikely(status != 0))
goto out_eio;
dprintk("%s ", server->data);
}
status = decode_pathname(xdr, &loc->rootpath);
if (unlikely(status != 0))
goto out_eio;
if (res->nlocations < NFS4_FS_LOCATIONS_MAXENTRIES)
res->nlocations++;
}
if (res->nlocations != 0)
status = NFS_ATTR_FATTR_V4_LOCATIONS;