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authorDarrick J. Wong <darrick.wong@oracle.com>2017-03-15 00:24:25 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-07 12:07:50 +0200
commit815414e7648b6d94cb81542dfb15cb71cbbd2ae9 (patch)
tree72d4a1b03061c94109668c557d999baca7ef76e0
parent11b4854772859d5a755cd575f68e2e2e3234ef43 (diff)
downloadlinux-aarch64-815414e7648b6d94cb81542dfb15cb71cbbd2ae9.tar.gz
xfs: verify inline directory data forks
commit 630a04e79dd41ff746b545d4fc052e0abb836120 upstream. When we're reading or writing the data fork of an inline directory, check the contents to make sure we're not overflowing buffers or eating garbage data. xfs/348 corrupts an inline symlink into an inline directory, triggering a buffer overflow bug. v2: add more checks consistent with _dir2_sf_check and make the verifier usable from anywhere. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/xfs/libxfs/xfs_dir2_priv.h2
-rw-r--r--fs/xfs/libxfs/xfs_dir2_sf.c87
-rw-r--r--fs/xfs/libxfs/xfs_inode_fork.c26
-rw-r--r--fs/xfs/libxfs/xfs_inode_fork.h2
-rw-r--r--fs/xfs/xfs_dir2_readdir.c11
-rw-r--r--fs/xfs/xfs_inode.c12
6 files changed, 122 insertions, 18 deletions
diff --git a/fs/xfs/libxfs/xfs_dir2_priv.h b/fs/xfs/libxfs/xfs_dir2_priv.h
index ef9f6ead96a4..860be99407bf 100644
--- a/fs/xfs/libxfs/xfs_dir2_priv.h
+++ b/fs/xfs/libxfs/xfs_dir2_priv.h
@@ -126,6 +126,8 @@ extern int xfs_dir2_sf_create(struct xfs_da_args *args, xfs_ino_t pino);
extern int xfs_dir2_sf_lookup(struct xfs_da_args *args);
extern int xfs_dir2_sf_removename(struct xfs_da_args *args);
extern int xfs_dir2_sf_replace(struct xfs_da_args *args);
+extern int xfs_dir2_sf_verify(struct xfs_mount *mp, struct xfs_dir2_sf_hdr *sfp,
+ int size);
/* xfs_dir2_readdir.c */
extern int xfs_readdir(struct xfs_inode *dp, struct dir_context *ctx,
diff --git a/fs/xfs/libxfs/xfs_dir2_sf.c b/fs/xfs/libxfs/xfs_dir2_sf.c
index c6809ff41197..96b45cd6c63f 100644
--- a/fs/xfs/libxfs/xfs_dir2_sf.c
+++ b/fs/xfs/libxfs/xfs_dir2_sf.c
@@ -629,6 +629,93 @@ xfs_dir2_sf_check(
}
#endif /* DEBUG */
+/* Verify the consistency of an inline directory. */
+int
+xfs_dir2_sf_verify(
+ struct xfs_mount *mp,
+ struct xfs_dir2_sf_hdr *sfp,
+ int size)
+{
+ struct xfs_dir2_sf_entry *sfep;
+ struct xfs_dir2_sf_entry *next_sfep;
+ char *endp;
+ const struct xfs_dir_ops *dops;
+ xfs_ino_t ino;
+ int i;
+ int i8count;
+ int offset;
+ __uint8_t filetype;
+
+ dops = xfs_dir_get_ops(mp, NULL);
+
+ /*
+ * Give up if the directory is way too short.
+ */
+ XFS_WANT_CORRUPTED_RETURN(mp, size >
+ offsetof(struct xfs_dir2_sf_hdr, parent));
+ XFS_WANT_CORRUPTED_RETURN(mp, size >=
+ xfs_dir2_sf_hdr_size(sfp->i8count));
+
+ endp = (char *)sfp + size;
+
+ /* Check .. entry */
+ ino = dops->sf_get_parent_ino(sfp);
+ i8count = ino > XFS_DIR2_MAX_SHORT_INUM;
+ XFS_WANT_CORRUPTED_RETURN(mp, !xfs_dir_ino_validate(mp, ino));
+ offset = dops->data_first_offset;
+
+ /* Check all reported entries */
+ sfep = xfs_dir2_sf_firstentry(sfp);
+ for (i = 0; i < sfp->count; i++) {
+ /*
+ * struct xfs_dir2_sf_entry has a variable length.
+ * Check the fixed-offset parts of the structure are
+ * within the data buffer.
+ */
+ XFS_WANT_CORRUPTED_RETURN(mp,
+ ((char *)sfep + sizeof(*sfep)) < endp);
+
+ /* Don't allow names with known bad length. */
+ XFS_WANT_CORRUPTED_RETURN(mp, sfep->namelen > 0);
+ XFS_WANT_CORRUPTED_RETURN(mp, sfep->namelen < MAXNAMELEN);
+
+ /*
+ * Check that the variable-length part of the structure is
+ * within the data buffer. The next entry starts after the
+ * name component, so nextentry is an acceptable test.
+ */
+ next_sfep = dops->sf_nextentry(sfp, sfep);
+ XFS_WANT_CORRUPTED_RETURN(mp, endp >= (char *)next_sfep);
+
+ /* Check that the offsets always increase. */
+ XFS_WANT_CORRUPTED_RETURN(mp,
+ xfs_dir2_sf_get_offset(sfep) >= offset);
+
+ /* Check the inode number. */
+ ino = dops->sf_get_ino(sfp, sfep);
+ i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
+ XFS_WANT_CORRUPTED_RETURN(mp, !xfs_dir_ino_validate(mp, ino));
+
+ /* Check the file type. */
+ filetype = dops->sf_get_ftype(sfep);
+ XFS_WANT_CORRUPTED_RETURN(mp, filetype < XFS_DIR3_FT_MAX);
+
+ offset = xfs_dir2_sf_get_offset(sfep) +
+ dops->data_entsize(sfep->namelen);
+
+ sfep = next_sfep;
+ }
+ XFS_WANT_CORRUPTED_RETURN(mp, i8count == sfp->i8count);
+ XFS_WANT_CORRUPTED_RETURN(mp, (void *)sfep == (void *)endp);
+
+ /* Make sure this whole thing ought to be in local format. */
+ XFS_WANT_CORRUPTED_RETURN(mp, offset +
+ (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
+ (uint)sizeof(xfs_dir2_block_tail_t) <= mp->m_dir_geo->blksize);
+
+ return 0;
+}
+
/*
* Create a new (shortform) directory.
*/
diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 25c1e078aef6..9653e964eda4 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -33,6 +33,8 @@
#include "xfs_trace.h"
#include "xfs_attr_sf.h"
#include "xfs_da_format.h"
+#include "xfs_da_btree.h"
+#include "xfs_dir2_priv.h"
kmem_zone_t *xfs_ifork_zone;
@@ -320,6 +322,7 @@ xfs_iformat_local(
int whichfork,
int size)
{
+ int error;
/*
* If the size is unreasonable, then something
@@ -336,6 +339,14 @@ xfs_iformat_local(
return -EFSCORRUPTED;
}
+ if (S_ISDIR(VFS_I(ip)->i_mode) && whichfork == XFS_DATA_FORK) {
+ error = xfs_dir2_sf_verify(ip->i_mount,
+ (struct xfs_dir2_sf_hdr *)XFS_DFORK_DPTR(dip),
+ size);
+ if (error)
+ return error;
+ }
+
xfs_init_local_fork(ip, whichfork, XFS_DFORK_PTR(dip, whichfork), size);
return 0;
}
@@ -856,7 +867,7 @@ xfs_iextents_copy(
* In these cases, the format always takes precedence, because the
* format indicates the current state of the fork.
*/
-void
+int
xfs_iflush_fork(
xfs_inode_t *ip,
xfs_dinode_t *dip,
@@ -866,6 +877,7 @@ xfs_iflush_fork(
char *cp;
xfs_ifork_t *ifp;
xfs_mount_t *mp;
+ int error;
static const short brootflag[2] =
{ XFS_ILOG_DBROOT, XFS_ILOG_ABROOT };
static const short dataflag[2] =
@@ -874,7 +886,7 @@ xfs_iflush_fork(
{ XFS_ILOG_DEXT, XFS_ILOG_AEXT };
if (!iip)
- return;
+ return 0;
ifp = XFS_IFORK_PTR(ip, whichfork);
/*
* This can happen if we gave up in iformat in an error path,
@@ -882,12 +894,19 @@ xfs_iflush_fork(
*/
if (!ifp) {
ASSERT(whichfork == XFS_ATTR_FORK);
- return;
+ return 0;
}
cp = XFS_DFORK_PTR(dip, whichfork);
mp = ip->i_mount;
switch (XFS_IFORK_FORMAT(ip, whichfork)) {
case XFS_DINODE_FMT_LOCAL:
+ if (S_ISDIR(VFS_I(ip)->i_mode) && whichfork == XFS_DATA_FORK) {
+ error = xfs_dir2_sf_verify(mp,
+ (struct xfs_dir2_sf_hdr *)ifp->if_u1.if_data,
+ ifp->if_bytes);
+ if (error)
+ return error;
+ }
if ((iip->ili_fields & dataflag[whichfork]) &&
(ifp->if_bytes > 0)) {
ASSERT(ifp->if_u1.if_data != NULL);
@@ -940,6 +959,7 @@ xfs_iflush_fork(
ASSERT(0);
break;
}
+ return 0;
}
/*
diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index 7fb8365326d1..132dc59fdde6 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -140,7 +140,7 @@ typedef struct xfs_ifork {
struct xfs_ifork *xfs_iext_state_to_fork(struct xfs_inode *ip, int state);
int xfs_iformat_fork(struct xfs_inode *, struct xfs_dinode *);
-void xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
+int xfs_iflush_fork(struct xfs_inode *, struct xfs_dinode *,
struct xfs_inode_log_item *, int);
void xfs_idestroy_fork(struct xfs_inode *, int);
void xfs_idata_realloc(struct xfs_inode *, int, int);
diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index 29816981b50a..6645a221bf8e 100644
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -71,22 +71,11 @@ xfs_dir2_sf_getdents(
struct xfs_da_geometry *geo = args->geo;
ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
- /*
- * Give up if the directory is way too short.
- */
- if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
- ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
- return -EIO;
- }
-
ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
ASSERT(dp->i_df.if_u1.if_data != NULL);
sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
- if (dp->i_d.di_size < xfs_dir2_sf_hdr_size(sfp->i8count))
- return -EFSCORRUPTED;
-
/*
* If the block number in the offset is out of range, we're done.
*/
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index e50636c9a89c..5af5e76db7a3 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -3491,6 +3491,7 @@ xfs_iflush_int(
struct xfs_inode_log_item *iip = ip->i_itemp;
struct xfs_dinode *dip;
struct xfs_mount *mp = ip->i_mount;
+ int error;
ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL|XFS_ILOCK_SHARED));
ASSERT(xfs_isiflocked(ip));
@@ -3573,9 +3574,14 @@ xfs_iflush_int(
if (ip->i_d.di_flushiter == DI_MAX_FLUSH)
ip->i_d.di_flushiter = 0;
- xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK);
- if (XFS_IFORK_Q(ip))
- xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK);
+ error = xfs_iflush_fork(ip, dip, iip, XFS_DATA_FORK);
+ if (error)
+ return error;
+ if (XFS_IFORK_Q(ip)) {
+ error = xfs_iflush_fork(ip, dip, iip, XFS_ATTR_FORK);
+ if (error)
+ return error;
+ }
xfs_inobp_check(mp, bp);
/*