From: David Howells dhowells@redhat.com
[ Upstream commit 158d58335393af3956a9c06f0816ee75ed1f1447 ]
Each AFS mountpoint has strings that define the target to be mounted. This is required to end in a dot that is supposed to be stripped off. The string can include suffixes of ".readonly" or ".backup" - which are supposed to come before the terminal dot. To add to the confusion, the "fs lsmount" afs utility does not show the terminal dot when displaying the string.
The kernel mount source string parser, however, assumes that the terminal dot marks the suffix and that the suffix is always "" and is thus ignored. In most cases, there is no suffix and this is not a problem - but if there is a suffix, it is lost and this affects the ability to mount the correct volume.
The command line mount command, on the other hand, is expected not to include a terminal dot - so the problem doesn't arise there.
Fix this by making sure that the dot exists and then stripping it when passing the string to the mount configuration.
Fixes: bec5eb614130 ("AFS: Implement an autocell mount capability [ver #2]") Reported-by: Jonathan Billings jsbillings@jsbillings.org Signed-off-by: David Howells dhowells@redhat.com Reviewed-by: Marc Dionne marc.dionne@auristor.com Tested-by: Jonathan Billings jsbillings@jsbillings.org Signed-off-by: Sasha Levin sashal@kernel.org --- fs/afs/mntpt.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/afs/mntpt.c b/fs/afs/mntpt.c index f532d6d3bd28..79bc5f1338ed 100644 --- a/fs/afs/mntpt.c +++ b/fs/afs/mntpt.c @@ -126,7 +126,7 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) if (src_as->cell) ctx->cell = afs_get_cell(src_as->cell);
- if (size > PAGE_SIZE - 1) + if (size < 2 || size > PAGE_SIZE - 1) return -EINVAL;
page = read_mapping_page(d_inode(mntpt)->i_mapping, 0, NULL); @@ -140,7 +140,9 @@ static int afs_mntpt_set_params(struct fs_context *fc, struct dentry *mntpt) }
buf = kmap(page); - ret = vfs_parse_fs_string(fc, "source", buf, size); + ret = -EINVAL; + if (buf[size - 1] == '.') + ret = vfs_parse_fs_string(fc, "source", buf, size - 1); kunmap(page); put_page(page); if (ret < 0)