The changeset ea31a4437c59219bf3ea946d58984b01a45a289c (nfs: Fix
misparsing of nfsv4 fs_locations attribute) causes the mountpath that is
calculated at the beginning of try_location() to be clobbered when we
later strncpy a non-nul terminated hostname using an incorrect buffer
length.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
---
fs/nfs/nfs4namespace.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/fs/nfs/nfs4namespace.c b/fs/nfs/nfs4namespace.c
index 30befc3..2a2a0a7 100644
--- a/fs/nfs/nfs4namespace.c
+++ b/fs/nfs/nfs4namespace.c
@@ -21,7 +21,9 @@
#define NFSDBG_FACILITY NFSDBG_VFS
/*
- * Check if fs_root is valid
+ * Convert the NFSv4 pathname components into a standard posix path.
+ *
+ * Note that the resulting string will be placed at the end of the buffer
*/
static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
char *buffer, ssize_t buflen)
@@ -99,21 +101,20 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
{
struct vfsmount *mnt = ERR_PTR(-ENOENT);
char *mnt_path;
- int page2len;
+ unsigned int maxbuflen;
unsigned int s;
mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
if (IS_ERR(mnt_path))
return mnt;
mountdata->mnt_path = mnt_path;
- page2 += strlen(mnt_path) + 1;
- page2len = PAGE_SIZE - strlen(mnt_path) - 1;
+ maxbuflen = mnt_path - 1 - page2;
for (s = 0; s < location->nservers; s++) {
const struct nfs4_string *buf = &location->servers[s];
struct sockaddr_storage addr;
- if (buf->len <= 0 || buf->len >= PAGE_SIZE)
+ if (buf->len <= 0 || buf->len >= maxbuflen)
continue;
mountdata->addr = (struct sockaddr *)&addr;
@@ -126,8 +127,8 @@ static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
continue;
nfs_set_port(mountdata->addr, NFS_PORT);
- strncpy(page2, buf->data, page2len);
- page2[page2len] = '\0';
+ memcpy(page2, buf->data, buf->len);
+ page2[buf->len] = '\0';
mountdata->hostname = page2;
snprintf(page, PAGE_SIZE, "%s:%s",
--
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