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| author | Jeff Layton <jlayton@redhat.com> | 2012-10-10 15:25:26 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2012-10-12 00:32:03 -0400 |
| commit | a608ca21f58ee44df5a71ba140e98498f3ebc2cd (patch) | |
| tree | 4ba6f5d5414ba9b579c8e41eb30c21a709537922 /init/do_mounts.c | |
| parent | 4fa6b5ecbf092c6ee752ece8a55d71f663d23254 (diff) | |
| download | lwn-a608ca21f58ee44df5a71ba140e98498f3ebc2cd.tar.gz lwn-a608ca21f58ee44df5a71ba140e98498f3ebc2cd.zip | |
vfs: allocate page instead of names_cache buffer in mount_block_root
First, it's incorrect to call putname() after __getname_gfp() since the
bare __getname_gfp() call skips the auditing code, while putname()
doesn't.
mount_block_root allocates a PATH_MAX buffer via __getname_gfp, and then
calls get_fs_names to fill the buffer. That function can call
get_filesystem_list which assumes that that buffer is a full page in
size. On arches where PAGE_SIZE != 4k, then this could potentially
overrun.
In practice, it's hard to imagine the list of filesystem names even
approaching 4k, but it's best to be safe. Just allocate a page for this
purpose instead.
With this, we can also remove the __getname_gfp() definition since there
are no more callers.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'init/do_mounts.c')
| -rw-r--r-- | init/do_mounts.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/init/do_mounts.c b/init/do_mounts.c index d3f0aeed2d39..f8a66424360d 100644 --- a/init/do_mounts.c +++ b/init/do_mounts.c @@ -353,8 +353,9 @@ static int __init do_mount_root(char *name, char *fs, int flags, void *data) void __init mount_block_root(char *name, int flags) { - char *fs_names = __getname_gfp(GFP_KERNEL - | __GFP_NOTRACK_FALSE_POSITIVE); + struct page *page = alloc_page(GFP_KERNEL | + __GFP_NOTRACK_FALSE_POSITIVE); + char *fs_names = page_address(page); char *p; #ifdef CONFIG_BLOCK char b[BDEVNAME_SIZE]; @@ -406,7 +407,7 @@ retry: #endif panic("VFS: Unable to mount root fs on %s", b); out: - putname(fs_names); + put_page(page); } #ifdef CONFIG_ROOT_NFS |