Revision 9e368259ad988356c4c95150fafd1a06af095d98 authored by Andrea Arcangeli on 30 November 2018, 22:09:25 UTC, committed by Linus Torvalds on 30 November 2018, 22:56:14 UTC
Patch series "userfaultfd shmem updates". Jann found two bugs in the userfaultfd shmem MAP_SHARED backend: the lack of the VM_MAYWRITE check and the lack of i_size checks. Then looking into the above we also fixed the MAP_PRIVATE case. Hugh by source review also found a data loss source if UFFDIO_COPY is used on shmem MAP_SHARED PROT_READ mappings (the production usages incidentally run with PROT_READ|PROT_WRITE, so the data loss couldn't happen in those production usages like with QEMU). The whole patchset is marked for stable. We verified QEMU postcopy live migration with guest running on shmem MAP_PRIVATE run as well as before after the fix of shmem MAP_PRIVATE. Regardless if it's shmem or hugetlbfs or MAP_PRIVATE or MAP_SHARED, QEMU unconditionally invokes a punch hole if the guest mapping is filebacked and a MADV_DONTNEED too (needed to get rid of the MAP_PRIVATE COWs and for the anon backend). This patch (of 5): We internally used EFAULT to communicate with the caller, switch to ENOENT, so EFAULT can be used as a non internal retval. Link: http://lkml.kernel.org/r/20181126173452.26955-2-aarcange@redhat.com Fixes: 4c27fe4c4c84 ("userfaultfd: shmem: add shmem_mcopy_atomic_pte for userfaultfd support") Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Mike Rapoport <rppt@linux.ibm.com> Reviewed-by: Hugh Dickins <hughd@google.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Jann Horn <jannh@google.com> Cc: Peter Xu <peterx@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: <stable@vger.kernel.org> Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 5618cf0
map.c
// SPDX-License-Identifier: GPL-2.0
/*
* linux/fs/hpfs/map.c
*
* Mikulas Patocka (mikulas@artax.karlin.mff.cuni.cz), 1998-1999
*
* mapping structures to memory with some minimal checks
*/
#include "hpfs_fn.h"
__le32 *hpfs_map_dnode_bitmap(struct super_block *s, struct quad_buffer_head *qbh)
{
return hpfs_map_4sectors(s, hpfs_sb(s)->sb_dmap, qbh, 0);
}
__le32 *hpfs_map_bitmap(struct super_block *s, unsigned bmp_block,
struct quad_buffer_head *qbh, char *id)
{
secno sec;
__le32 *ret;
unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
if (hpfs_sb(s)->sb_chk) if (bmp_block >= n_bands) {
hpfs_error(s, "hpfs_map_bitmap called with bad parameter: %08x at %s", bmp_block, id);
return NULL;
}
sec = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
if (!sec || sec > hpfs_sb(s)->sb_fs_size-4) {
hpfs_error(s, "invalid bitmap block pointer %08x -> %08x at %s", bmp_block, sec, id);
return NULL;
}
ret = hpfs_map_4sectors(s, sec, qbh, 4);
if (ret) hpfs_prefetch_bitmap(s, bmp_block + 1);
return ret;
}
void hpfs_prefetch_bitmap(struct super_block *s, unsigned bmp_block)
{
unsigned to_prefetch, next_prefetch;
unsigned n_bands = (hpfs_sb(s)->sb_fs_size + 0x3fff) >> 14;
if (unlikely(bmp_block >= n_bands))
return;
to_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block]);
if (unlikely(bmp_block + 1 >= n_bands))
next_prefetch = 0;
else
next_prefetch = le32_to_cpu(hpfs_sb(s)->sb_bmp_dir[bmp_block + 1]);
hpfs_prefetch_sectors(s, to_prefetch, 4 + 4 * (to_prefetch + 4 == next_prefetch));
}
/*
* Load first code page into kernel memory, return pointer to 256-byte array,
* first 128 bytes are uppercasing table for chars 128-255, next 128 bytes are
* lowercasing table
*/
unsigned char *hpfs_load_code_page(struct super_block *s, secno cps)
{
struct buffer_head *bh;
secno cpds;
unsigned cpi;
unsigned char *ptr;
unsigned char *cp_table;
int i;
struct code_page_data *cpd;
struct code_page_directory *cp = hpfs_map_sector(s, cps, &bh, 0);
if (!cp) return NULL;
if (le32_to_cpu(cp->magic) != CP_DIR_MAGIC) {
pr_err("Code page directory magic doesn't match (magic = %08x)\n",
le32_to_cpu(cp->magic));
brelse(bh);
return NULL;
}
if (!le32_to_cpu(cp->n_code_pages)) {
pr_err("n_code_pages == 0\n");
brelse(bh);
return NULL;
}
cpds = le32_to_cpu(cp->array[0].code_page_data);
cpi = le16_to_cpu(cp->array[0].index);
brelse(bh);
if (cpi >= 3) {
pr_err("Code page index out of array\n");
return NULL;
}
if (!(cpd = hpfs_map_sector(s, cpds, &bh, 0))) return NULL;
if (le16_to_cpu(cpd->offs[cpi]) > 0x178) {
pr_err("Code page index out of sector\n");
brelse(bh);
return NULL;
}
ptr = (unsigned char *)cpd + le16_to_cpu(cpd->offs[cpi]) + 6;
if (!(cp_table = kmalloc(256, GFP_KERNEL))) {
pr_err("out of memory for code page table\n");
brelse(bh);
return NULL;
}
memcpy(cp_table, ptr, 128);
brelse(bh);
/* Try to build lowercasing table from uppercasing one */
for (i=128; i<256; i++) cp_table[i]=i;
for (i=128; i<256; i++) if (cp_table[i-128]!=i && cp_table[i-128]>=128)
cp_table[cp_table[i-128]] = i;
return cp_table;
}
__le32 *hpfs_load_bitmap_directory(struct super_block *s, secno bmp)
{
struct buffer_head *bh;
int n = (hpfs_sb(s)->sb_fs_size + 0x200000 - 1) >> 21;
int i;
__le32 *b;
if (!(b = kmalloc_array(n, 512, GFP_KERNEL))) {
pr_err("can't allocate memory for bitmap directory\n");
return NULL;
}
for (i=0;i<n;i++) {
__le32 *d = hpfs_map_sector(s, bmp+i, &bh, n - i - 1);
if (!d) {
kfree(b);
return NULL;
}
memcpy((char *)b + 512 * i, d, 512);
brelse(bh);
}
return b;
}
void hpfs_load_hotfix_map(struct super_block *s, struct hpfs_spare_block *spareblock)
{
struct quad_buffer_head qbh;
__le32 *directory;
u32 n_hotfixes, n_used_hotfixes;
unsigned i;
n_hotfixes = le32_to_cpu(spareblock->n_spares);
n_used_hotfixes = le32_to_cpu(spareblock->n_spares_used);
if (n_hotfixes > 256 || n_used_hotfixes > n_hotfixes) {
hpfs_error(s, "invalid number of hotfixes: %u, used: %u", n_hotfixes, n_used_hotfixes);
return;
}
if (!(directory = hpfs_map_4sectors(s, le32_to_cpu(spareblock->hotfix_map), &qbh, 0))) {
hpfs_error(s, "can't load hotfix map");
return;
}
for (i = 0; i < n_used_hotfixes; i++) {
hpfs_sb(s)->hotfix_from[i] = le32_to_cpu(directory[i]);
hpfs_sb(s)->hotfix_to[i] = le32_to_cpu(directory[n_hotfixes + i]);
}
hpfs_sb(s)->n_hotfixes = n_used_hotfixes;
hpfs_brelse4(&qbh);
}
/*
* Load fnode to memory
*/
struct fnode *hpfs_map_fnode(struct super_block *s, ino_t ino, struct buffer_head **bhp)
{
struct fnode *fnode;
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ino, 1, "fnode")) {
return NULL;
}
if ((fnode = hpfs_map_sector(s, ino, bhp, FNODE_RD_AHEAD))) {
if (hpfs_sb(s)->sb_chk) {
struct extended_attribute *ea;
struct extended_attribute *ea_end;
if (le32_to_cpu(fnode->magic) != FNODE_MAGIC) {
hpfs_error(s, "bad magic on fnode %08lx",
(unsigned long)ino);
goto bail;
}
if (!fnode_is_dir(fnode)) {
if ((unsigned)fnode->btree.n_used_nodes + (unsigned)fnode->btree.n_free_nodes !=
(bp_internal(&fnode->btree) ? 12 : 8)) {
hpfs_error(s,
"bad number of nodes in fnode %08lx",
(unsigned long)ino);
goto bail;
}
if (le16_to_cpu(fnode->btree.first_free) !=
8 + fnode->btree.n_used_nodes * (bp_internal(&fnode->btree) ? 8 : 12)) {
hpfs_error(s,
"bad first_free pointer in fnode %08lx",
(unsigned long)ino);
goto bail;
}
}
if (le16_to_cpu(fnode->ea_size_s) && (le16_to_cpu(fnode->ea_offs) < 0xc4 ||
le16_to_cpu(fnode->ea_offs) + le16_to_cpu(fnode->acl_size_s) + le16_to_cpu(fnode->ea_size_s) > 0x200)) {
hpfs_error(s,
"bad EA info in fnode %08lx: ea_offs == %04x ea_size_s == %04x",
(unsigned long)ino,
le16_to_cpu(fnode->ea_offs), le16_to_cpu(fnode->ea_size_s));
goto bail;
}
ea = fnode_ea(fnode);
ea_end = fnode_end_ea(fnode);
while (ea != ea_end) {
if (ea > ea_end) {
hpfs_error(s, "bad EA in fnode %08lx",
(unsigned long)ino);
goto bail;
}
ea = next_ea(ea);
}
}
}
return fnode;
bail:
brelse(*bhp);
return NULL;
}
struct anode *hpfs_map_anode(struct super_block *s, anode_secno ano, struct buffer_head **bhp)
{
struct anode *anode;
if (hpfs_sb(s)->sb_chk) if (hpfs_chk_sectors(s, ano, 1, "anode")) return NULL;
if ((anode = hpfs_map_sector(s, ano, bhp, ANODE_RD_AHEAD)))
if (hpfs_sb(s)->sb_chk) {
if (le32_to_cpu(anode->magic) != ANODE_MAGIC) {
hpfs_error(s, "bad magic on anode %08x", ano);
goto bail;
}
if (le32_to_cpu(anode->self) != ano) {
hpfs_error(s, "self pointer invalid on anode %08x", ano);
goto bail;
}
if ((unsigned)anode->btree.n_used_nodes + (unsigned)anode->btree.n_free_nodes !=
(bp_internal(&anode->btree) ? 60 : 40)) {
hpfs_error(s, "bad number of nodes in anode %08x", ano);
goto bail;
}
if (le16_to_cpu(anode->btree.first_free) !=
8 + anode->btree.n_used_nodes * (bp_internal(&anode->btree) ? 8 : 12)) {
hpfs_error(s, "bad first_free pointer in anode %08x", ano);
goto bail;
}
}
return anode;
bail:
brelse(*bhp);
return NULL;
}
/*
* Load dnode to memory and do some checks
*/
struct dnode *hpfs_map_dnode(struct super_block *s, unsigned secno,
struct quad_buffer_head *qbh)
{
struct dnode *dnode;
if (hpfs_sb(s)->sb_chk) {
if (hpfs_chk_sectors(s, secno, 4, "dnode")) return NULL;
if (secno & 3) {
hpfs_error(s, "dnode %08x not byte-aligned", secno);
return NULL;
}
}
if ((dnode = hpfs_map_4sectors(s, secno, qbh, DNODE_RD_AHEAD)))
if (hpfs_sb(s)->sb_chk) {
unsigned p, pp = 0;
unsigned char *d = (unsigned char *)dnode;
int b = 0;
if (le32_to_cpu(dnode->magic) != DNODE_MAGIC) {
hpfs_error(s, "bad magic on dnode %08x", secno);
goto bail;
}
if (le32_to_cpu(dnode->self) != secno)
hpfs_error(s, "bad self pointer on dnode %08x self = %08x", secno, le32_to_cpu(dnode->self));
/* Check dirents - bad dirents would cause infinite
loops or shooting to memory */
if (le32_to_cpu(dnode->first_free) > 2048) {
hpfs_error(s, "dnode %08x has first_free == %08x", secno, le32_to_cpu(dnode->first_free));
goto bail;
}
for (p = 20; p < le32_to_cpu(dnode->first_free); p += d[p] + (d[p+1] << 8)) {
struct hpfs_dirent *de = (struct hpfs_dirent *)((char *)dnode + p);
if (le16_to_cpu(de->length) > 292 || (le16_to_cpu(de->length) < 32) || (le16_to_cpu(de->length) & 3) || p + le16_to_cpu(de->length) > 2048) {
hpfs_error(s, "bad dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
if (((31 + de->namelen + de->down*4 + 3) & ~3) != le16_to_cpu(de->length)) {
if (((31 + de->namelen + de->down*4 + 3) & ~3) < le16_to_cpu(de->length) && s->s_flags & SB_RDONLY) goto ok;
hpfs_error(s, "namelen does not match dirent size in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
ok:
if (hpfs_sb(s)->sb_chk >= 2) b |= 1 << de->down;
if (de->down) if (de_down_pointer(de) < 0x10) {
hpfs_error(s, "bad down pointer in dnode %08x, dirent %03x, last %03x", secno, p, pp);
goto bail;
}
pp = p;
}
if (p != le32_to_cpu(dnode->first_free)) {
hpfs_error(s, "size on last dirent does not match first_free; dnode %08x", secno);
goto bail;
}
if (d[pp + 30] != 1 || d[pp + 31] != 255) {
hpfs_error(s, "dnode %08x does not end with \\377 entry", secno);
goto bail;
}
if (b == 3)
pr_err("unbalanced dnode tree, dnode %08x; see hpfs.txt 4 more info\n",
secno);
}
return dnode;
bail:
hpfs_brelse4(qbh);
return NULL;
}
dnode_secno hpfs_fnode_dno(struct super_block *s, ino_t ino)
{
struct buffer_head *bh;
struct fnode *fnode;
dnode_secno dno;
fnode = hpfs_map_fnode(s, ino, &bh);
if (!fnode)
return 0;
dno = le32_to_cpu(fnode->u.external[0].disk_secno);
brelse(bh);
return dno;
}
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