From: "Darrick J. Wong" <darrick.wong@xxxxxxxxxx> 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. Signed-off-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx> Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx> --- v2: add more checks consistent with _dir2_sf_check and make the verifier usable from anywhere. --- fs/xfs/libxfs/xfs_dir2_priv.h | 2 + fs/xfs/libxfs/xfs_dir2_sf.c | 87 ++++++++++++++++++++++++++++++++++++++++++ fs/xfs/libxfs/xfs_inode_fork.c | 26 +++++++++++-- fs/xfs/libxfs/xfs_inode_fork.h | 2 +- fs/xfs/xfs_dir2_readdir.c | 11 ------ fs/xfs/xfs_inode.c | 12 ++++-- 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); /* -- 2.11.0